• TABLE OF CONTENTS
HIDE
 Title Page
 Table of Contents
 List of Figures
 List of Tables
 Acknowledgement
 Preface
 Introduction
 Sytematics and biogeography
 Life history
 History and development of the...
 Utilization patterns
 Utilization potentials
 Environmental needs
 Conclusions and recommendation...
 Bibliography
 Definitions
 List of acronyms






Group Title: Technical paper - Florida Sea Grant Program ;, no. 9
Title: The biology and Florida fishery of the stone crab, Menippe mercenaria (Say), with emphasis on Southwest Florida
CITATION PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00072275/00001
 Material Information
Title: The biology and Florida fishery of the stone crab, Menippe mercenaria (Say), with emphasis on Southwest Florida
Series Title: Technical paper - Florida Sea Grant Program no. 9
Physical Description: v, 82 p. : ill. ; 28 cm.
Language: English
Creator: Bert, Theresa M
Warner, Richard E ( joint author )
Kessler, Lorin D. ( joint author )
Publisher: State University System of Florida, Sea Grant Program
Place of Publication: Gainesville
Publication Date: 1978
 Subjects
Subject: Crab fisheries -- Florida   ( lcsh )
Menippe mercenaria   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 72-79.
Statement of Responsibility: by Theresa M. Bert, Richard E. Warner and Lorin D. Kessler.
General Note: "October 1978."
Funding: Technical paper (Florida Sea Grant College) ;
 Record Information
Bibliographic ID: UF00072275
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000990239
oclc - 04740956
notis - AEW7151

Table of Contents
    Title Page
        Title Page 1
        Title Page 2
    Table of Contents
        Table of Contents
    List of Figures
        Page i
        Page ii
    List of Tables
        Page iii
    Acknowledgement
        Page iv
    Preface
        Page v
    Introduction
        Page 1
    Sytematics and biogeography
        Page 1
        Classification
            Page 1
        Species description
            Page 2
            Page 3
            Page 4
            Page 5
            Page 6
            Page 7
    Life history
        Page 8
        Larval phase
            Page 8
            Page 9
        Juvenile phase
            Page 10
            Page 11
        Adult phase
            Page 12
            Page 13
            Page 14
            Page 15
    History and development of the stone crab fishery
        Page 16
        Introduction
            Page 16
        Development of the industry
            Page 17
            Page 18
            Page 19
            Page 20
        Development of techniques
            Page 21
            Page 22
            Page 23
            Page 24
            Page 25
        Ecologically sound fishing methods
            Page 26
            Page 27
            Page 28
            Page 29
    Utilization patterns
        Page 30
        Magnitude of the fishery
            Page 30
            Page 31
            Page 32
            Page 33
            Page 34
            Page 35
            Page 36
            Page 37
            Page 38
            Page 39
            Page 40
            Page 41
        Management of the fishery
            Page 42
            Page 43
            Page 44
            Page 45
            Page 46
    Utilization potentials
        Page 47
        Present trends
            Page 47
            Page 48
            Page 49
            Page 50
            Page 51
            Page 52
            Page 53
            Page 54
        Future possibilities
            Page 55
            Page 56
            Page 57
            Page 58
        Mariculture possibilities
            Page 59
            Page 60
            Page 61
            Page 62
    Environmental needs
        Page 63
        Basic requirements of the animal
            Page 63
        Meeting the requirements
            Page 64
            Page 65
            Page 66
    Conclusions and recommendations
        Page 67
        Page 68
        Page 69
        Page 70
        Page 71
    Bibliography
        Page 72
        Page 73
        Page 74
        Page 75
        Page 76
        Page 77
        Page 78
        Page 79
    Definitions
        Page 80
        Page 81
    List of acronyms
        Page 82
Full Text













THE BIOLOGY AND FLORIDA FISHERY OF THE STONE CRAB,
Menippe mereenarit (Say),
WITH EMPHASIS ON SOUTHWEST FLORIDA

by

Theresa*M. Bert
Richard E. Warner
and Lorin D. Kessler

TECHNICAL PAPER NO. 9
October 1978


Florida Sea Grant
















THE BIOLOGY AND FLORIDA FISHERY OF THE STONE CRAB,
Menippe mereenarit (Say),
WITH EMPHASIS ON SOUTHWEST FLORIDA

by

Theresa#M. Bert
Richard E. Warner
and Lorin D. Kessler

TECHNICAL PAPER NO. 9
October 1978









The information contained in this paper was
developed under the auspices of the Monroe County
Marine Resource Inventory, and funded by the
Comprehensive Employment Training Act. This
document is a Technical Paper of the State
University System of Florida Sea College Program,
2001 McCarty Hall, University of Florida,
Gainesville, FL 32611. Technical Papers are
duplicated in limited quantities for specialized
audiences requiring rapid access to information,
which may be unedited.



Policy conclusions or recommendations herein
are not necessarily those of the Florida Sea Grant
College or the State University System of Florida.







TABLE OF CONTENTS

Page

LIST OF FIGURES ................ ...................................

LIST OF TABLES.................................... .......... I..

1. INTRODUCTION........................................ ....... 1

2. SYSTEMATICS AND BIOGEOGRAPHY.............................. 1

2.1. Classification ...................................... 1
2.2. Species Description.................................. 1
2.3. Biogeography. ....................................... 8

3. LIFE HISTORY... ........... ................................. 8

3.1. Larval Phase......................................... 8
3.2. Juvenile Phase...................................... 10
3.3. Adult Phase .......................................... 12

4. HISTORY AND DEVELOPMENT OF THE STONE CRAB FISHERY........... 16

4.1. Introduction......................................... 16
4.2. Development of the Industry.......................... 17
4.3. Development of Techniques............................ 21
4.4. Ecologically Sound Fishing Methods.................... 26

5. UTILIZATION PATTERNS........................................ 30
5.1. Magnitude of the Fishery............................. 30
5.2. Management of the Fishery............................ 42

6. UTILIZATION POTENTIALS.................................... 47
6.1. Present Trends...................................... 47
6.2. Future Possibilities................................ 55
6.3. Mariculture Possibilities............................ 59

7. ENVIRONMENTAL NEEDS....................... ................. 63

7.1. Basic Requirements of the Animal..................... 63
7.2. Meeting the Requirements............................. 64

8. CONCLUSIONS AND RECOMMENDATIONS............................ 67

9. BIBLIOGRAPHY.............................................. 72
9.1. Literature Cited..................................... 72
9.2. Further References.................................. 78

10. APPENDIX................................................... 80
10.1. Definitions......................................... 80
10.2. List of Acronyrms.................................... 82









LIST OF FIGURES


Figure Page

1. Larval Stages Of The Stone Crab............................ 3.

2. Detail Of Cheliped, And Adult, Dorsal View, Of The Stone
Crab........................................................ 4

3. Male And Female Stone Crabs................................. 5

4. Major Cheliped, Or Crusher, Of The Stone Crab............... 6

5. Minor Cheliped, Or Pincer, Of The Stone Crab................ 7

6. Principal Florida West Coast Stone Crab Fishing Centers..... 9

7. Early (Late 1800's To Early 1960's) And Present Fishing
Boundaries For The Everglades-Florida Bay Stone Crab
Fishery....................................................* 19

8. Present Extent Of Monroe County Stone Crab Fishing Grounds.. 20

9. Standard Stone Crab Trap And Buoy........................... 22

10. Trap Lift And Automated Winch For Stone Crab Traps.......... 24

11. Correct Method Of Breaking Stone Crab Claws................. 25

12. Incorrectly Broken Stone Crab Claw (Wound>14 mm)........... 28

13. Open Wound From Incorrectly Broken Stone Crab Claw.......... 29

14. Total Volume Of Stone Crabs (Whole Crab Weight) Landed,
1953-1978, For The State Of Florida, West Coast Of Florida,
Monroe County, And Collier County........................... 31

15. Percentage Of Statewide Stone Crab Landings Attributable To
Monroe And Collier Counties, 1953-1976..................... 32

16. Total Dockside Value Of Landings From The Stone Crab Fishery
For Monroe And Collier Counties And The State Of Florida,
From 1953-1976.............................................. 37

17. Number Of Stone Crab Permits Issued In The State Of Florida,
Monroe County, and Collier County, 1968-1977................ 39

18. Percentage Of Total Trapped Female Stone Crab Population
With Eggs, By Month, In Florida, From The Cedar Key Region,
Biscayne Bay, And The Lower E-FB Region..................... 44






LIST OF FIGURES (cont'd)

Figure Page

19. Percentage Of Female Stone Crabs In Trapped Population, By
Month, In Biscayne Bay, Florida............................ 46

20. Dockside Price Of Stone Crab Claws (Adjusted To Consumer
Price Index) And Important Consumer Price Indices, 1955-
1975...................................................... 49

21. Volume Of Stone Crabs Landed Per Permit Issued, 1968-1975,
For The State Of Florida, Monroe County, And Collier County. 51

22. Yearly Income From The Stone Crab Fishery Per Permit Issued,
1968-1975, For The State Of Florida, Monroe County, And
Collier County............................................... 51









LIST OF TABLES


Table Page

I. Some Early Recorded Stone Crab Landings In Monroe County... 18

II. Monroe County Stone Crab Landings, By Month (1968-1977).... 34

III. Collier County Stone Crab Landings, By Month (1968-1977)... 35

IV. Price Per Pound For The Stone Crab (Whole Crab Price),
1955-1977.................................................. 36

V. Stone Crab Permits, 1968-1975 ............................. 40

VI. Estimated Trap Density In Area Of E-FB Stone Crab Fishing
Region Utilized By Monroe County Fishermen (Exclusive Of
Everglades National Park Waters--Approximately 520 sq km
(200 sq mi)--And Those Fishermen With Permits To Fish In
The Park--25 Permits) During The 1975-76 Season............ 41

VII. Average Estimated Value Of Claws Produced Per Trap Night
For 1-Man and 3-Man Stone Crab Fishing Operations For The
1970-71 Season And 1975-76 Season.......................... 50

VIII. Comparison Of Survival And Developmental Rates At Differ-
ent Temperatures And Salinities For Larvae Of M. mercenaria 60

IX. Summary Of Results From Larval Culture (Egg To First Crab)
Of The Stone Crab (Excluding Ong and Costlow, 1970)........ 61

X. Survival Rate For Stone Crab Mariculture Encountered By
Yang and Krantz, 1976...................................... 61








ACKNOWLEDGMENTS


Innumerable recreational and commercial fishermen and others involved
in the stone crab fishery were heavily relied upon for extremely valuable
and otherwise unobtainable information. These individuals freely gave
their valuable time to council the senior writer on many occasions. The
writers offer their sincerest thanks to: Mr. Allan Armitt, Mr. Peter
Bartholi, Mr. Charlie Brown, Mr. Tim Daniels, Mr. Steve Daniels, Mr.
Gary Graves, Mr. Howell Grimm, Mr. Pete Logan, "Sanchez", Col. Frank
Taylor, and their mates and associates, all of Monroe county. These
persons spent countless hours discussing stone crabs with the senior
writer and provided their opinions of the preliminary draft. The manage-
ment and personnel of Angelo's Fisheries, Charlie Brown Fisheries, Keys
Fisheries, and Marathon Seafood, of Monroe county provided data, hospital-
ity, and bases of operation for the field work involved in this study.
The Ernest Hamilton Stone Crab Company, Collier county, supplied the
basis for a comparison of the problems of the Collier and Monroe county
fisheries, as well as a lifeline to the Collier county stone crab fishery.

Of equal importance was the assistance of our scientific colleagues
in the critical review of the manuscript and in providing valuable con-
sultation in its preparation. Of particular assistance in data and infor-
mation collection and interpretation were Mr. J.R. (Dick) Sullivan (DNR)
and Mr. Gary Davis (NPS), who kindly provided not only their expertise
in this area but also many preliminary findings and important insights
from their own research, without which this manuscript would be far less
comprehensive. Dr. Jim Cato furnished much-needed advice regarding
economics of the fishery. Ms. Deborah Shaw, Mr. Chris Combs, Mr. Douglas
Gregory, Jr., and Mr. John Stevely also offered valuable suggestions and
new ideas. Dr. Harold J. Humm (University of South Florida) reviewed
the manuscript.

Numerous individuals contributed assistance in preparation of the
manuscript, for which they are gratefully acknowledged. Mr. Ernest Snell
and Mr. Elmer Allen (NMFS) and the office of Ms. Marjorie Gore (DNR)
ceaselessly searched through their files to uncover the requested statis-
tics on landings and permits. Ms. Charlotte Howard typed the preliminary
draft and Mr. H.S. Gamble assisted in preparation of some figures. Lt.
Ralph Tingley and the Florida Marine Patrol kindly supplied information
regarding Florida laws.

Financial support for this undertaking was provided by the Monroe
County Board of Commissioners, which made available Comprehensive Employ-
ment Training Act funds for the Marine Resource Inventory. Their continu-
ing sympathetic and interested support, and that of the Monroe County
Manpower Planning Subcouncil, is gratefully acknowledged.







PREFACE


During review and final preparation of this manuscript for publi-
cation, the controversy between trappers and shrimp trawling fishermen
that was predicted (Section 6.2.1) surfaced during the 1977-78 stone
crab season. This triggered immediate action by the Gulf of Mexico
Fisheries Management Council to formulate a management plan for the
stone crab fishery before the conflict could again occur in the 1978-79
season. At the time this manuscript was sent to press, the stone crab
management plan was in first draft form and was in the process of re-
view by various industry and scientific subcommittees of the Gulf of
Mexico Fisheries Management Council. Thus some of the recommendations
mentioned here in Section 8 were already being implemented as this
document was being printed for publication. Much information necessary
for formulation of the stone crab management plan was derived from this
study.






1. INTRODUCTION


The delicious flavor of stone crab (Menippe mercenaria) claws was
a well-kept secret of Florida seafood connoisseurs for many years. Recent-
ly, however, widespread interest has begun to develop in the delicacy.
The result has been the rapid mushrooming of the stone crab fishery into
a multi-million dollar industry employing several thousand people only
since the late 1960's. By far its most dramatic growth has been in south-
west Florida, notably Monroe and Collier counties. Although the overall
economic importance of the stone crab fishery statewide is relatively
small, compared to the vast shrimp and spiny lobster fisheries, it is a
vital part of the fishing industry in these counties.

This report is a synthesis of today's extent of knowledge regarding
the natural history of the stone crab, and an evaluation of the stone crab fish-
ing industry, which proved to be a complex and complicated endeavor. Coop-
eration by fishermen, processors, and scientists currently studying the
problem was relied upon for much of the information presented. Where
possible, evaluations based on unrecorded accounts were supported by
available reported data. In all cases regarding important assessments
of the magnitude and economics of the fishery, at least three independent
information sources were consulted.

This manuscript contains the only complete summary of the research
conducted on the stone crab to date and evaluation of the growth, impor-
tance, and input of its fishery. It is hoped that this study will add
considerably to the knowledge of the relationship of the organism to its
fishery. In addition, baseline data for future use in monitoring a
commercially exploited area are provided, as well as a better understand-
ing of the relationship of the southwest Florida stone crab fishery to
that of the rest of the state.

Because of the broad audience that this paper is intended to serve,
a glossary of scientific terms are included for the layman in an appendix.
A listing of the many acronyms used throughout the paper follows the
glossary.


2. SYSTEMATICS AND BIOGEOGRAPHY


2.1. Classification

Because of its tremendous size and complexity, classification of
the phylum Arthropoda (horseshoe crabs, chelicerates, crustaceans,
insects, centipedes, millipedes) has evolved highly subdivided categories.
Below is a complete listing of the taxonomy of the stone crab and some
characteristics that put it in that category.

Phylum Arthropoda (jointed legs)
Class Crustacea (having a shell)
Subclass Malacostraca (eight thoracic and six abdominal plates in the
skeleton)






1. INTRODUCTION


The delicious flavor of stone crab (Menippe mercenaria) claws was
a well-kept secret of Florida seafood connoisseurs for many years. Recent-
ly, however, widespread interest has begun to develop in the delicacy.
The result has been the rapid mushrooming of the stone crab fishery into
a multi-million dollar industry employing several thousand people only
since the late 1960's. By far its most dramatic growth has been in south-
west Florida, notably Monroe and Collier counties. Although the overall
economic importance of the stone crab fishery statewide is relatively
small, compared to the vast shrimp and spiny lobster fisheries, it is a
vital part of the fishing industry in these counties.

This report is a synthesis of today's extent of knowledge regarding
the natural history of the stone crab, and an evaluation of the stone crab fish-
ing industry, which proved to be a complex and complicated endeavor. Coop-
eration by fishermen, processors, and scientists currently studying the
problem was relied upon for much of the information presented. Where
possible, evaluations based on unrecorded accounts were supported by
available reported data. In all cases regarding important assessments
of the magnitude and economics of the fishery, at least three independent
information sources were consulted.

This manuscript contains the only complete summary of the research
conducted on the stone crab to date and evaluation of the growth, impor-
tance, and input of its fishery. It is hoped that this study will add
considerably to the knowledge of the relationship of the organism to its
fishery. In addition, baseline data for future use in monitoring a
commercially exploited area are provided, as well as a better understand-
ing of the relationship of the southwest Florida stone crab fishery to
that of the rest of the state.

Because of the broad audience that this paper is intended to serve,
a glossary of scientific terms are included for the layman in an appendix.
A listing of the many acronyms used throughout the paper follows the
glossary.


2. SYSTEMATICS AND BIOGEOGRAPHY


2.1. Classification

Because of its tremendous size and complexity, classification of
the phylum Arthropoda (horseshoe crabs, chelicerates, crustaceans,
insects, centipedes, millipedes) has evolved highly subdivided categories.
Below is a complete listing of the taxonomy of the stone crab and some
characteristics that put it in that category.

Phylum Arthropoda (jointed legs)
Class Crustacea (having a shell)
Subclass Malacostraca (eight thoracic and six abdominal plates in the
skeleton)






1. INTRODUCTION


The delicious flavor of stone crab (Menippe mercenaria) claws was
a well-kept secret of Florida seafood connoisseurs for many years. Recent-
ly, however, widespread interest has begun to develop in the delicacy.
The result has been the rapid mushrooming of the stone crab fishery into
a multi-million dollar industry employing several thousand people only
since the late 1960's. By far its most dramatic growth has been in south-
west Florida, notably Monroe and Collier counties. Although the overall
economic importance of the stone crab fishery statewide is relatively
small, compared to the vast shrimp and spiny lobster fisheries, it is a
vital part of the fishing industry in these counties.

This report is a synthesis of today's extent of knowledge regarding
the natural history of the stone crab, and an evaluation of the stone crab fish-
ing industry, which proved to be a complex and complicated endeavor. Coop-
eration by fishermen, processors, and scientists currently studying the
problem was relied upon for much of the information presented. Where
possible, evaluations based on unrecorded accounts were supported by
available reported data. In all cases regarding important assessments
of the magnitude and economics of the fishery, at least three independent
information sources were consulted.

This manuscript contains the only complete summary of the research
conducted on the stone crab to date and evaluation of the growth, impor-
tance, and input of its fishery. It is hoped that this study will add
considerably to the knowledge of the relationship of the organism to its
fishery. In addition, baseline data for future use in monitoring a
commercially exploited area are provided, as well as a better understand-
ing of the relationship of the southwest Florida stone crab fishery to
that of the rest of the state.

Because of the broad audience that this paper is intended to serve,
a glossary of scientific terms are included for the layman in an appendix.
A listing of the many acronyms used throughout the paper follows the
glossary.


2. SYSTEMATICS AND BIOGEOGRAPHY


2.1. Classification

Because of its tremendous size and complexity, classification of
the phylum Arthropoda (horseshoe crabs, chelicerates, crustaceans,
insects, centipedes, millipedes) has evolved highly subdivided categories.
Below is a complete listing of the taxonomy of the stone crab and some
characteristics that put it in that category.

Phylum Arthropoda (jointed legs)
Class Crustacea (having a shell)
Subclass Malacostraca (eight thoracic and six abdominal plates in the
skeleton)








Series Eumalocostracea
Superorder Eucarida (skeletal plates fused together)
Order Decapoda (ten legs)
Suborder Reptantia (crawlers)
Section Brachyura (greatly reduced tails)
Subsection Brachygnatha (last pair of legs not modified
into swimming paddles)
Superfamily Brachyrhyncha (short snouts)
Family Xanthidae (mud crabs)
Genus Menippe
Species mercenaria

2.2. Species Description

The genus Menippe has a broad oval carapace. The eyes are on short,
thick stalks and the claws are massive and slightly unequal in size.
The fingers, one unmoving and one jointed at the base, are pointed and
possess a few large teeth. Four species of the genus are known in the
Americas: Menippe mercenaria, M. frontalis, M. obtusa, and M. nodifrons.
Only M. mercenaria and M. nodifrons are present on the Atlantic coast.
Of the two, only M. mercenaria is harvested within the area of primary
focus of this study.

2.2.1. Larva

A free-swimming planktonic larva is characteristic of most marine
crustaceans, including the stone crab. The larva of the stone crab
undergoes many developmental stages before becoming a recognizable crab.
Five zoeal stages and one megalopa normally occur (Figure 1). The zoea
is easily recognized by the very long rostral spine and a pair of lateral
spines from the posterior edge of the carapace. The megalopa is reminiscent
of the probable macruran (shrimp-like appearance) ancestry of Brachyurans.

2.2.2. Juvenile

The juvenile appears very similar to the adult. It is distinguish-
able by a dark carapace (Hay and Shore, 1918; Wass, 1955), black or deep
maroon, changing to dull red with pale dots as the stone crab increases
in size (Manning, 1961). The juvenile stone crab has a light band or
spot on the outer surface of the manus, legs that are red-cream color
banded, and a greater distance between the eyes than the adult. In
small specimens, less than 15 mm (0.59 in) carapace width (CW), the stri-
dulatory or sound producing ridges cannot be easily detected (Manning,
1961) and the lateral teeth are smoother than in adults.

2.2.3. Adult

The adult stone crab has an oval body, two-thirds as long as it is
wide (Figure 2). Males can be distinguished from females by their
slimmer abdomens (Figure 3). Both males and females possess abnormally
large, unequal claws, the major and minor chelae, that bear stridulation
ridges. If the major chela has never been lost, its width is equal to
34% of the carapace width (Powell and Gunter, 1968). The major chela, or
crusher (Figure 4), has a large basal tooth on the immovable finger
(Figure 2); the minor chela, or pincer (Figure 5), has numerous small







Figure 1.





A.


Imm (0.04 in)


Larval Stages Of The Stone Crab. A. First Zoeal Stage.
B. Second Zoeal stage. C. Third Zoeal Stage. D. Fourth
Zoeal Stage. E. Fifth Zoeal Stage. F. M opa Stage.
(A-E after Porter, 1960; F after Hymen, 19 .
B. Rostral
SSpine

--Eye Antenna SpinLateral
& Eye ^^. ^Spine







Figure 2.


Detail Of Cheliped, And Adult, Dorsal View,Of The
Stone Crab (Rathbun, 1930).


Cheliped, Stone Crab


Stridulation
f Ridges


Propodus
(Immovable Finger
plus Manus)


Adult, Stone Crab


Later
Lobes
(or t


Dactylus








Male And Female Stone Crabs (Redrawn from Futch, 1966).


Thoracic Ste

























Telson Cover
Sternum and
Abdomen


)domen with
Telson


Male Stone Crab


Female Stone Crab


Figure 3.














Major Cheliped, Or Crusher, Of The Stone Crab.


-- vo,


--------------------------m


I.. ~ q%


4: ; ,


r

'U-=


Figure 4.












Minor Cheliped, Or Pincer, Of The Stone Crab.


C

S~b


r

~:

~-
j

,r .;r~r" ,.. ~.
i-
r
--


Figure 5.


- rg--- -- ~








teeth and a slightly larger sub-basal tooth (Savage, et al., 1975). The
presence of stridulation ridges, a larger size, less prominent interorbital
lobes, and a smooth dorsal carapace mottled with dusky gray are the most
easily identifiable features distinguishing Menippe mercenaria from M.
nodifrons.

2.3. Biogeography

The stone crab inhabits warm temperate, subtropical, and tropical
waters. It is found along the Atlantic coast from Cape Hatteras, North
Carolina, (Hay and Shore, 1918) to Mexico (Rathbun, 1930), in Cuba,
Jamaica, the Bahamas (Karandeyva and Silva, 1973), and Yucatan (Williams,
1965). It has also been collected throughout the Gulf of Mexico (Behre,
1950; Gunter, 1950; McRae, 1950; Whitten, et al., 1950; Wass, 1955;
Menzel and Hopkins, 1956; Tabb, et al., 1962). The depth at which it
has been found ranges from the intertidal zone (McRae, 1950) to 54 m
(177 ft) (Bullis and Thompson, 1965).

The stone crab is found in commercially harvestable quantities
along certain areas of the continental shelf of Florida: the Cedar Keys
region; offshore from Tampa Bay and Boca Grande; and the Everglades-
Florida Bay region, including the Ten Thousand Islands (Figure 6). Its
greatest concentration apparently extends from the coastal waters ad-
jacent to Collier county and throughout Florida Bay.

The closely related Menippe nodifrons is far less common and has a
narrower distributional range than M. mercenaria (Rathbun, 1930). M.
nodifrons appears to be a species more common to the Caribbean. Rathbun
also noted a specimen obtained from the French Congo in Africa. In the
Gulf of Mexico, M. nodifrons has been reported only from Cameron,
Louisiana (Rabhbun, 1930), and may be absent from Florida Gulf coastal
waters (Savage, et al., 1975).


3. LIFE HISTORY


The stone crab undergoes three major phases in development: the
larval, juvenile, and adult. Each phase is unique in several aspects of
the animal's ecology: growth and development, habitat, migrations, trophic
level, and behavior.

3.1. Larval Phase

Of the stages in the life of the stone crab, the least is known about
the ecology of the larva. The small size (less than 2 mm, or 0.08 in) and
similarity in appearance of Xanthid crab larvae make them at best very
difficult to recognize at the species level. When one considers the num-
ber of species in the family Xanthidae and the many stages involved in the
larval development of each, even a simple task such as habitat establish-
ment becomes nearly insurmountable. Thus much information has yet to be
collected on the larval stages of the stone crab.








teeth and a slightly larger sub-basal tooth (Savage, et al., 1975). The
presence of stridulation ridges, a larger size, less prominent interorbital
lobes, and a smooth dorsal carapace mottled with dusky gray are the most
easily identifiable features distinguishing Menippe mercenaria from M.
nodifrons.

2.3. Biogeography

The stone crab inhabits warm temperate, subtropical, and tropical
waters. It is found along the Atlantic coast from Cape Hatteras, North
Carolina, (Hay and Shore, 1918) to Mexico (Rathbun, 1930), in Cuba,
Jamaica, the Bahamas (Karandeyva and Silva, 1973), and Yucatan (Williams,
1965). It has also been collected throughout the Gulf of Mexico (Behre,
1950; Gunter, 1950; McRae, 1950; Whitten, et al., 1950; Wass, 1955;
Menzel and Hopkins, 1956; Tabb, et al., 1962). The depth at which it
has been found ranges from the intertidal zone (McRae, 1950) to 54 m
(177 ft) (Bullis and Thompson, 1965).

The stone crab is found in commercially harvestable quantities
along certain areas of the continental shelf of Florida: the Cedar Keys
region; offshore from Tampa Bay and Boca Grande; and the Everglades-
Florida Bay region, including the Ten Thousand Islands (Figure 6). Its
greatest concentration apparently extends from the coastal waters ad-
jacent to Collier county and throughout Florida Bay.

The closely related Menippe nodifrons is far less common and has a
narrower distributional range than M. mercenaria (Rathbun, 1930). M.
nodifrons appears to be a species more common to the Caribbean. Rathbun
also noted a specimen obtained from the French Congo in Africa. In the
Gulf of Mexico, M. nodifrons has been reported only from Cameron,
Louisiana (Rabhbun, 1930), and may be absent from Florida Gulf coastal
waters (Savage, et al., 1975).


3. LIFE HISTORY


The stone crab undergoes three major phases in development: the
larval, juvenile, and adult. Each phase is unique in several aspects of
the animal's ecology: growth and development, habitat, migrations, trophic
level, and behavior.

3.1. Larval Phase

Of the stages in the life of the stone crab, the least is known about
the ecology of the larva. The small size (less than 2 mm, or 0.08 in) and
similarity in appearance of Xanthid crab larvae make them at best very
difficult to recognize at the species level. When one considers the num-
ber of species in the family Xanthidae and the many stages involved in the
larval development of each, even a simple task such as habitat establish-
ment becomes nearly insurmountable. Thus much information has yet to be
collected on the larval stages of the stone crab.





Figure 6. Principal Florida West Coast Stone Crab Fishing Centers.


I

I
CEDAR

KEYS

REGION

TAMPA BAY Pin-i
ellas (
REO -


Levy


Hillsboro


nmm -m


EVERGLADES-
FLORIDA BAY
REGION


49Al'








3.1.1. Growth, Habitat, Migrations, Behavior

Stone crab eggs hatch at any time of day or night (Hyman, 1925). The
prezoea sheds its cuticle within a few minutes after leaving the egg
and assumes the first zoeal form. The five zoeal stages are all planktonic.
Zoeae are capable of feeble movements in the vertical direction but are
essentially at the mercy of water currents. Zoeae live in the water col-
umn near the surface until the organism is ready to change into megalopa
form. The megalopa too is planktonic but is thought to swim near the
bottom, testing the sea floor for a suitable place to settle (Thorsen,
1949).

Each larval stage lasts from three to six days and requires a molt
to assume the succeeding stage (Porter, 1960). From hatching to metamor-
phosis to true crab form takes less than six weeks (Ong and Costlow, 1970).
The larvae grow exponentially but the growth rate decreases during the
megalopa stage.

Survival rates are unknown except in larvae raised in culture. Lar-
val mortality in nature could be expected to be extremely high, since the
larvae spend a long time in the water column (Thorsen, 1949) and require
warm water (30 C or 86 F) and oceanic salinities (30-35 parts per thousand,
or ppt) for most rapid growth (Ong and Costlow, 1970). Although Bender
(1971) reported that females attempt to move to this type of environment
to spawn, they are not always able to do so. Thus, in certain broad
areas of shallow water where salinity and temperature can fluctuate
dramatically, such as Everglades National Park (ENP) waters, larvae
hatched from resident crabs may have high mortality rates due to these
factors alone. These localities may have a substantial recruitment from
larvae developed in adjacent waters that move into the area to settle
and metamorphose.

3.1.2. Trophic Level

Stone crab larvae are vigorous carnivores (Mootz and Epifanio, 1974).
Food consumption reaches a maximum at the megalops stage and declines
prior to metamorphosis. Stone crab larvae eat smaller planktonic animals.
Although their natural diet is not known, several studies have shown that
they thrive on Artemia (brine shrimp) nauplii (Porter, 1960; Savage and
McMahan, 1968; Cheung, 1969; Mootz and Epifanio, 1974).

Planktonic larvae have extremely low survival rates, primarily due
to predation (Thorsen, 1949). For example, in the blue crab, whose pelagic
larval life span and reproductive capacity is similar to that of the stone
crab,only one tenthousandth of one percent (0.000001) of eggs become
mature adults (Engel, 1958). The minute size and pelagic habitat of stone
crab larvae make them easy prey for a host of fishes and invertebrates,
including other zooplankton. The vast number of eggs produced by the
stone crab is an adaptive mechanism to offset heavy larval predation.

3.2. Juvenile Phase

3.2.1. Growth

The transition from juvenile to adult coloration and the gradual
adoption of adult characters normally occurs when the stone crab measures







from about 15 to 30 mm (0.59 to 1.18 in) carapace length (CL) (Manning,
1961). For convenience, animals measuring less than 30 mm carapace width
(CW) are usually classified as juveniles. Difference in sex can be
readily identified at 9 mm (0.35 in) CW (McRae, 1950; Savage and McMahan,
1968).

Growth rates have not yet been established in natural conditions
and vary in the laboratory, apparently increasing with warmer temperatures
and more saline water (Bender, 1971). Savage and McMahan (1968) found
that juvenile growth averaged 15% with each molt. In their study, crabs
of 5 mm (0.20 in) CW molted an average of once every 40 days, with inter-
molt periods increasing with increasing carapace width. Thus, adulthood
may not be reached until the stone crab is at least one year old. Bender
believed that sexual maturity is reached in the fall after the first year
of growth, presenting a new recruitment of individuals to copulate in
the winter.

3.2.2. Habitat and Migration

Existing data on habitat and migrations are incomplete and somewhat
conflicting, although some conclusions can be drawn. Hay and Shore (1918)
found that young juveniles of 10 to 15 mm (0.39 to 0.59 in) CW migrate
inshore to warm bays and estuaries. In the northern Florida Gulf, juven-
iles have been found in salinities of 24 to 35 ppt (McRae, 1950; Wass,
1955; Menzel and Nichy, 1958). In contrast, Manning (1961) did not record
juveniles in water of less than 31 ppt during his three-year study in
Florida Bay. Williams (1965) and Bender (1971) have indicated that juven-
iles occupy areas of slightly deeper water than adults. Some questions
arise, however, concerning sampling methods used in these studies. Re-
searchers currently believe that the trawling method used for sampling
was biased toward retrieving juveniles. Juveniles have been found in
channels in North Carolina (Hay and Shore, 1918), and in deeper seagrass flats
(McRae, 1950; Bender, 1971) and along the bottom of tidal channels in
Florida Bay (Manning, 1961).

Since they do not dig burrows (Powell and Gunter, 1968), juveniles
utilize readily available hiding places that offer close proximity to
food items. Crabs that are very small (less than 1.3 cm, or 0.51 in, CW)
have a body weight that can be supported by muddy channel bottoms (McRae,
1950; Bender, 1971) and seagrass blades (Bender, 1971). Turtle grass,
Thalassia testudinum, is preferred (Wass, 1955), probably because its
broad blades support a wide variety of epiphytic and epizoic organisms
that are utilized as food. In the Florida Keys, sponges, gorgonians,
empty shells, shell bottom, and Sargassum mats are also shelters for
juveniles. Larger juveniles are very numerous on oyster reefs and rock
piles (Menzel and Nichy, 1958).

3.2.3. Trophic Level

The juvenile stone crab is an opportunistic carnivore and has been
shown to feed on a wide variety of animal protein sources in captivity,
including beef liver and chicken parts (Savage and McMahan, 1968). Al-
though no analysis of the natural diet of the juvenile stone crab has
been conducted yet, Bender (1971) reported that they favor polychaetes,
seagrass blades, small bivalves, and oyster drills.







The juvenile stone crab is subject to predation by a wider variety
of large predators than is the adult. In northern Florida, a serious
predator of M. mercenaria less than 10 mm (0.39 in) CL is the mud crab
Neopanope taxana Stimpson (Landers, 1954). In addition to being more
highly susceptible than adults to traditional stone crab predators,
juveniles may fall prey to bottom-feeding and cruising carnivores and
omnivores because they do not burrow. Large grouper and black sea bass
consume juveniles less than 30 mm (1.18 in) CW (Bender, 1971).

3.2.4. Behavior

The juvenile stone crab commonly adopts passive defense mechanisms
when annoyed. It will often feign death (Powell and Gunter, 1968).
Vigorous stridulation is frequently initiated (Powell and Gunter, 1968;
Bender, 1917), though specifically what this activity accomplishes is as
yet unknown. However, the juvenile stone crab can be aggressive when
provoked (Yang and Krantz, 1976). Crabs less than 20 mm (0.79 in) CW
will attack a moving object and hug it with the claws (Powell and Gunter,
1968).

3.3. Adult Phase

3.3.1. Reproduction

Mating. Most information available on reproduction of the stone crab
centers on spawning or the maturation of eggs and larvae. Very little data
are concerned with the mating season. Bender (1971) believed that mating
occurred from November to March at Cedar Key, with a peak of activity in
November. Binford (1913) noted a peak of mating activity in August in
North Carolina. In the Florida Keys area, reproductive studies have been
concerned with the mating, spawning, and rearing of the stone crab in
culture only (Cheung, 1968; Yang, 1972;Yang and Krantz, 1976).

It is difficult to hypothesize when molting and mating season may
occur in nature, if indeed there is a season. Evidence indicates that the
female stone crab molts and mates soon after spawning is terminated (Noe,
1967; Bender, 1971). Spawning season is at least extended through
November (Manning, 1961; Sullivan, in press) and appears to extend the
year around in Florida Bay (T.M. Bert, pers. obsn.). A peak in copulation
occurs late in the year (November or December) in the Everglades-Florida
Bay (E-FB) region, soon after most spawning has ended.

Copulation. The copulatory act has been documented by Binford (1913),
Savage (1971a), and Yang (1972). Savage confirmed the mating behavior
under natural conditions. The male crab will guard- a burrow in which there
is a recently molted female or one that will soon molt. The male flips the
female with his perieopods, opens her abdomen by using his own, and, crad-
ling the female in his walking legs, inserts the first pair of pleopods
containing the penes into the female's gonopores. The spermatozoa travel
along grooves in the first pleopods driven by a piston-like movement of the
second pleopods. The female curls her telson loosely over the male's
carapace. The claws of the male are extended in a defensive position while
those of the female are held closely to her body. The spermatozoa are
transferred into the female where they are stored in a compact mass until
spawning, when only a portion are used at a time. A single copulation can






provide sperm for fertilization of eggs during an entire spawning season.
Up to thirteen spawnings from a single copulation have been recorded
(Cheung, 1969). Some credence has been given to the possibility that female
stone crabs are polygamous or may store sperm from more than one male from
copulations at different molts (Williams, 1965; Cheung, 1968).

Spawning. Spawning season of the stone crab lengthens in duration with
movement southward (William, 1965; Noe, 1967; Cheung, 1969; Bender, 1971)
until it extends the year around in the Biscayne Bay and Florida Bay areas.
All researchers who have investigated environmental factors influencing
spawning agree that temperature is the most important regulator of spawning
frequency (Noe, 1967; Cheung, 1969; Bender, 1971), with 280C (85P) as the
temperature of optimum ovarian development (Cheung, 1969). In contrast,
new egg formation is inhibited in the fall by decreasing light intensity
(Cheung, 1969).

Females reach sexual maturity as small as 33.7 mm (1.31 in) CW (J.R.
Sullivan, DNR, pers. comm.) and bear a very large number of eggs with each
spawning. The number of eggs per sponge, as the egg mass is called, ranges
from 160,000 to 350,000 (Noe, 1967) and is closely related to size (McRae,
1950). Binford (1913) detailed spawning behavior:

"When a female is ready to lay eggs, she assumes an upright position
and holds the abdomen out from her body so that it and the exopods
of the abdominal appendages form a basket into which the eggs are run.
They there become attached to the hairs of the endopods of the appen-
dages and pass through the embryonic stages of their development,
which requires nine to thirteen days. The eggs then hatch and the
larvae escape. The female then cleans off the egg shells and their
stalks from the hairs of the pleopods and, after one day to three
weeks, she spawns again. Eight days is a very common length for the
period between the hatching of one batch of eggs and the spawning
of the next."

The average number of spawns between molts is 4.5 (Cheung, 1969). Thus,
even small female stone crabs have an annual egg production of about 500,000
eggs.

3.2.2. Growth


Growth of the adult stone crab is influenced by a number of external
and internal factors, particularly in the female:

1. salinity may effect molting (Noe, 1967);

2. low temperatures cause a reduction in amount of growth attained
between molts (Savage, 1971b) and may prevent molting (Passano,
1960b);

3. summer growth is inhibited by initial ovarian development in
spawning season, even though warmer temperatures favor growth
(Cheung, 1969);

4. ovarian development and egg development and incubation under the
abdomen inhibit molting (Cheung, 1969).
13








As with the larval and juvenile phases, adult growth is enhanced in
warmer months. In Florida, the sea water temperature seldom falls below
the temperature that is thought to prohibit molting (150C or 590F)
(Passano, 1960b), so males may molt throughout the year (Bender, 1971).
J.R. Sullivan, DNR,(pers. comm.) has evidence that males may increase cara-
pace width by 10 mm (0.39 in) at each molt. Intermolt periods are lengthy
in the adult however--six months is the minimum (Cheung, 1969)--and any
inhibition can result in a significant decrease in growth and rate of
regeneration of missing appendages. Some researchers believe that, un-
like many other decapod crustaceans, the stone crab has a terminal molt
and will reach a maximum size at a CW between 110 and 120 mm (4.33 and
4.72 in) (Cheung, 1969). However, since molting is inhibited by reproduction,
the female is restricted to cooler months of the year to molt. Most
females molt from November to spring (Noe, 1967; Bender, 1971) with some
shedding occurring throughout the year. Bender attributed the smaller
size of the female to this seemingly poorly adapted reproductive-growth
strategy.

3.3.3. Habitat

Adult stone crabs characteristically inhabit burrows, 15 to 127 cm
(6 to 50 in) deep, in.Thalassia flats and along the sides and edges of
channels (McRae, 1950). Burrows may be as close as 20 to 30 cm (7.9 to
11.8 in) apart in the vicinity of ample food. Mature adult stone crabs
construct complex burrows in which four chambers can be identified
(Bender, 1971). The burrows of larger stone crabs (CW greater than 75 mm,
or 3.0 in) are dug obliquely (Powell and Gunter, 1968) and have openings
perpendicular to the direction of prevalent water flow (Bender, 1971).
This construction probably functions to minimize sand accumulation in the
burrow. Powell and Gunter (1968) observed that younger adults (44 to 73
mm, or 1.7 to 2.9 in, CW) excavated shorter burrows extending straight
downward. They found no crabs less than 43.2 mm (1.7 in) CW in burrows.

Adults will also live on rocky or shell bottom, sand, and mud. In
Texas and northwestern Florida, they inhabit oyster reefs (McRae, 1950;
Powell and Gunter, 1968) and rock jetties (Whitten, et al., 1950).
McRae (1950) found the greatest abundance of crabs in the ship channel.

Stone crab burrows also furnish temporary homes to a conglomerate
of other marine organisms (McRae, 1950; Bender, 1971). Transient crabs of
all kinds (including stone crabs), mollusks and other invertebrates, and
even fish make use of the burrows for protection, to seek food, and for
survival. Stone crabs themselves use their burrows for a number of reasons:

1. females that molt in winter remain in burrows, probably for
protection (Bender, 1971);

2. when caught in shallow water during cold weather, crabs will seal
themselves in the burrows for protection (McRae, 1950);

3. mating pairs of stone crabs can often be found in burrows
(Bender, 1971);

4. stone crabs commonly stockpile food' in their burrows, partic-
ularly mollusks (Powell and Gunter, 1968).







Adult stone crabs are hardy and can tolerate most environmental
extremes within their distributional range. They live in moderate to high
salinity waters. They are able to withstand salinities considerably lower
or higher than the normal oceanic concentration (35 ppt), if given the
opportunity to accustom themselves to the environment (Karandeyva and
Silva, 1973). Thus, they may not be endangered by seasonal salinity fluc-
tuations similar to those occurring in Florida Bay (although Tabb, et al.,
1962, found them only in water above 28 ppt).

3.3.4. Migration

Fishermen for many years have followed seasonal migrations during
crabbing season. Some stone crabbers in Monroe county say that overall
size of the catch for that year depends on the migrating population of
crabs, since the resident population is "fished out" early in the season.
Early researchers thought that no definite migratory patterns occurred but
did acknowledge that some seasonal population shifts may be attributed
to reproductive behavior (McRae, 1950; Bender, 1971). Sullivan (in press)
has recently obtained information on movements that substantiates this
idea. It appears that the onset of these movements may be triggered by
several stimuli.

Movements can be divided into two classes: nondirectional and direct-
ional. The movements cover distances ranging from a few meters (feet)
to several kilometers (miles).

Nondirectional movements seem to show no consistent yearly pattern,
but are related to environmental factors that vary from year to year. An
increase in food abundance on seagrass flats during summer may stimulate
an increase in the general population (Bender, 1971), or in spawning females
(Noe, 1967). Water turbulence associated with storms will often provoke
localized "walking" in stone crabs. Fishermen agree that highest catch
rates are immediately following a "Norther". Stone crabs may move, par-
ticularly to deeper water, to seek shelter in burrows and plug the openings
in cold weather (Bender, 1971). Tidal currents and contour of the sea
floor also exercise an influence on the direction of local crab movements
(Bender, 1971).

Directional movements do not appear to be random. They are.usually
seasonal mass movements of primarily one sex and/or size class. Male
stone crabs in Florida seem to live farther offshore than do females, who
are year-around residents of shallow seagrass flats. Notable increases in
the male population on the flats following spawning season have been noted
throughout the Florida Gulf coast (McRae, 1950; Bender, 1971; Sullivan,
in press) and at Biscayne Bay (Noe, 1967). Evidently a large population
of males moves shoreward, via channels in the area, to mate with the molting
females. An influx of females (5 to 7 cm, 2.0 to 2.8 in, CW) reaching
sexual maturity also occurs in nearshore areas during early summer (Powell
and Gunter, 1968; Bender, 1971) to mate in the fall.

3.3.5. Trophic Level

Shellfish of all kinds are the staple food of the adult stone crab
(Powell and Gunter, 1968; Bender, 1971). It has also been observed to
eat other crustaceans, including its own species. The stone orab can exist
for up to two weeks without additional eating, after consuming a maximum of
food (Sushchenya and Claro, 1973).








The stone crab's large powerful claws forestall many would-be predators.
However, it is vulnerable to Octopus species. Fishermen frequently find
octopi in their traps, and usually where there are octopi, there are few
or no remaining live crabs. Fishermen state that, before the advent of
today's sturdy traps, the Florida horse conch (Pleuroploca gigantea) and
sea turtles would destroy the traps by breaking the fragile lathes, de-
vouring the crabs inside.

3.3.6. Behavior

Like the juvenile, the adult stone crab initially adopts a defensive
behavior pattern when threatened (Powell and Gunter, 1968). However, when
continually annoyed, the stone crab will grasp the offensive object with
its cheliped and pinch, exerting considerable force. If the cheliped is
grasped while the crab is holding an object, the crab may autotomize, or
voluntarily amputate, the cheliped.

Stridulation, once thought to be absent in adults (Guinot-Dumortier
and Dumortier, 1960), is reported to be occasional and erratic (Powell and
Gunter, 1968; Bender, 1971). Its function has not been determined. Bender
mentioned that crabs frequently stridulated when held aloft. Some fisher-
men'believe that crabs "talk" stridulatee) during mating season.

There is a difference of opinion regarding the time of day that the
stone crab reaches a peak of activity. Evidence also suggests that the
stone crab may follow monthly cycles in degree of mobility. Monroe County
fishermen generally agree that the highest yield per trap occurs during the
new moon phase and that crabs are more mobile at this time of the month.

Many instances involving habitat and migration have been documented
in which a distinct sex and size class has been almost exclusively involved.
Adaptations of this type are common and function to avoid niche competition
within a species, thus insuring a greater probability of species survival.
Additional intraspecific pressure inherent to the stone crab that may accen-
tuate the need for sex and size class separation include the cannibalistic
nature of the animal, territoriality, or competition between and within
sexes.


4. HISTORY AND DEVELOPMENT OF THE STONE CRAB FISHERY


4.1. Introduction

This paper now turns from a synthesis of known biological data on
the stone-crab to focus on the fishery that the resource supports. Special
attention will be given to the Everglades-Florida Bay (E-FB) fishing grounds.
The information is presented, and a number of viable conclusions and
recommendations are offered dealing with possible research needs and fishery
management options that could provide a sustained yield and insure adequate
population levels.








The stone crab's large powerful claws forestall many would-be predators.
However, it is vulnerable to Octopus species. Fishermen frequently find
octopi in their traps, and usually where there are octopi, there are few
or no remaining live crabs. Fishermen state that, before the advent of
today's sturdy traps, the Florida horse conch (Pleuroploca gigantea) and
sea turtles would destroy the traps by breaking the fragile lathes, de-
vouring the crabs inside.

3.3.6. Behavior

Like the juvenile, the adult stone crab initially adopts a defensive
behavior pattern when threatened (Powell and Gunter, 1968). However, when
continually annoyed, the stone crab will grasp the offensive object with
its cheliped and pinch, exerting considerable force. If the cheliped is
grasped while the crab is holding an object, the crab may autotomize, or
voluntarily amputate, the cheliped.

Stridulation, once thought to be absent in adults (Guinot-Dumortier
and Dumortier, 1960), is reported to be occasional and erratic (Powell and
Gunter, 1968; Bender, 1971). Its function has not been determined. Bender
mentioned that crabs frequently stridulated when held aloft. Some fisher-
men'believe that crabs "talk" stridulatee) during mating season.

There is a difference of opinion regarding the time of day that the
stone crab reaches a peak of activity. Evidence also suggests that the
stone crab may follow monthly cycles in degree of mobility. Monroe County
fishermen generally agree that the highest yield per trap occurs during the
new moon phase and that crabs are more mobile at this time of the month.

Many instances involving habitat and migration have been documented
in which a distinct sex and size class has been almost exclusively involved.
Adaptations of this type are common and function to avoid niche competition
within a species, thus insuring a greater probability of species survival.
Additional intraspecific pressure inherent to the stone crab that may accen-
tuate the need for sex and size class separation include the cannibalistic
nature of the animal, territoriality, or competition between and within
sexes.


4. HISTORY AND DEVELOPMENT OF THE STONE CRAB FISHERY


4.1. Introduction

This paper now turns from a synthesis of known biological data on
the stone-crab to focus on the fishery that the resource supports. Special
attention will be given to the Everglades-Florida Bay (E-FB) fishing grounds.
The information is presented, and a number of viable conclusions and
recommendations are offered dealing with possible research needs and fishery
management options that could provide a sustained yield and insure adequate
population levels.







4.2. Development Of The Industry

4.2.1. Southwest Florida

Commercial. The meat of the stone crab, Florida's answer to the Amer-
ican lobster, has been enjoyed by native Floridians since the days of the
Glades Indians. Stone crabs provided food to settlers for local consump-
tion throughout Monroe county. The people of Flamingo, Florida (Figure 7)
were frequently cut off from external food sources and relied heavily upon
readily available seafood items, such as the stone crab, to keep their
families from starving (Tebeau, 1968).


The stone crab fishery did not begin growing perceptibly until the
early 1960's. Prior to that time, stone crabs were caught as an accessory
product of the spiny lobster (Panulirus argus) industry (Schroeder, 1925).
The market for crabs was restricted to restaurants and consumers in the
immediate area of the fishery (Powell and Gunter, 1968). In many instances,
whole crabs had to be taken to Miami to be sold. Only the very best were
accepted. Fishermen say that, as recently as 1962, supply exceeded demand
and sometimes whole stone crabs were sold for only $.30 per dozen, if a
market could be found for them at all. Upon establishment of a broader
market, composed chiefly of restaurants in large cities, the stone crab
industry began steadily and rapidly rising in volume and value of product
sold. With only minor setbacks, the industry has grown to its present
day status.

Recreational. Noncommercially, stone crabs have been caught by
trappers and divers. Diving for stone crab claws has developed into a
popular sport in the Tampa Bay region. However, its present importance to
the overall catch in the E-FB region is probably negligible. Stone crabs
are taken by recreational divers who are usually seeking tropical reef fish
or spiny lobsters. Crabs are caught by either teasing the crab up into the
water column and grasping the claws when it is suspended, or by pulling
the crab out of its burrow with a hooked pole. (Technically, this method
of hooking stone crabs is illegal (370.13 Fl. Stat.).)

4.2.2. Monroe County

Early Development. Little information has been documented regarding
the earliest days of the Florida Keys stone crab industry. Schroeder
(1924) provides the most extensive information. He said:

"These crustaceans are caught throughout the year, but the most
favorable fishing obtains during February, March, and April. They
are found rather near the shore and generally not farther than
one mile from land."

In those days, the stone crab was a delicacy and demand occasionally
exceeded supply, contradictory to the 1950's and early 1960's.

"...the Key West catch varies from about 10 to 50 dozens a day
during the winter and spring season...Small crabs, measuring about
3 inches in width across the carapace, sell at retail for about
$1 a dozen, while those 4 or more inches in width bring from $1.50
to $2."








Although the fishery steadily grew (Table I), by 1922 it represented only
0.6% of the total seafood landings in Monroe county.


Table I. Some Early Recorded Stone Crab Landings In Monroe County
(Schroeder, 1925).
Year Volume Landed
Pounds Kilograms
1895 4,680 2,123
1902 8,610 3,905
1918 18,400 8,346
1919 22,000 9,979



Recent Development. The E-FB stone crab fishing region has grown
over five-fold in the past ten years (Figure 7) and currently spans an
area of approximately 9,850 sq km (3,800 sq mi). Monroe county fishermen
have expanded their fishing range from localities among the Keys and shal-
low water regions close to their homes to encompass the entire area from the
Harbor Keys to the vicinity of Highland Point above the Shark River basin
(Figure 8). From its original area, estimated at about 900 sq km (350 sq
mi), the Monroe county fishery has expanded to include about 5.050 sq km
(1,950 sq mi)_(Figure 8).

Three centers of activity have developed for stone crab fishing in
the Keys. Upper Keys fishermen operate small one-man boats for easy
maneuverability in the shallow water of Florida Bay to Cape Sable. Fishing
effort is concentrated in the areas of Sandy Key and the center of ENP waters.
Fishermen working out of Marathon may travel as far as the Harbor Keys,
or above the Shark River basin and eastward to Sandy Key. After the onset
of net fishing season (November 15), they move their traps from net fishing
grounds and fish an area north of a line drawn from the Harbor Keys to Cape
Sable light and less than about 45 to 50 ft (14 to 16 m) deep. (This
arrangement was set up by the Monroe county fishermen to allow for just
apportionment of the available grounds and resources.) Marathon fishermen
generally set their traps in deeper water and need boats that are operable
in heavier seas and can accommodate a three-man crew. A third small center
for stone crab fishing exists in the Lower Keys. With the exception of a
few boats, crabbers in that area are single-man operators and stay essen-
tially in shallow water in the "Back Country", or Gulf of Mexico waters
among the Keys.

Relatively few Monroe county fishermen rely on crabbing exclusively
as their source of income. Large boat fishermen combine crabbing with
crawfishing (fishing for spiny lobster). The stone crab and spiny lobster
fishing season overlap. Since the differences between crabbing and craw-
fishing are very slight, it is a simple matter for the fishermen to
combine the two. The effort devoted to fishing for either species depends
upon "how well it is catching" during the course of the season. Most
large boat fishermen do not normally utilize any auxilliary fishery other
than crawfishing, since their boats would have to be rigged in an entirely











Figure 7. Early (Late 1800's To Early 1960's) And Present Fish
Boundaries For The Evergl1des-Florida Bay Stone Crab Fishery.


Cape :'**. .
Romano -. ."
-";. .
1 Ten \ :. :-
Thousand
I Islands










CAPE ". 'e *''.{ ey Largo

I... '
S1East in i ,
ca "
\ f / Upper Matecumbe
I / Key


; Or Long Key
S THE BACK COUNTRY ,
,. ?ey ac Legend:

Sey Vaca Early
9 "'"*^^^L-^" Boundary **--. ---
/Present
Boundary ~-----
-fc~*. tM-f* .- -; *












Figure 8. Present Extent Of


Monroe County Stone Crab Fishing Grounds.



/Point/ o
Point/ /


Area
Of
Greatest
Fishing
Intensity


Contend


ty



Evergades
National E
Park \
.r

s

\ 0
cs~


Largo


Matecumbe


West


N


SMarathon

loll, l








different manner. Small boat fishermen, particularly those fishing the
grounds near the Key West vicinity, support themselves by crawfishing
and crabbing from late summer through spring and sponging, bottom fishing,
or collecting tropical fish during the early and mid-summer months.

4.3. Development Of Techniques

4.3.1. Early Methods

Small open boats powered by oars, sails, or small gasoline engines,
perforated containers to catch crabs in, strong arms, and shallow water
were the early stone crabber's tools. Aside from spiny lobster traps,
just about anything from old lettuce boxes to cans with holes punched in
them were used. Bait came from scrap and trash fish discarded by other
fishermen. Stingrays were frequently used by fishermen working near Key
West, E-FB fishermen set out their traps in Florida Bay, the Ten Thousand
Islands, and channels between the Keys.

4.3.2. Today's Methods

The Trap. The standard stone crab trap (Figure 9) is of either
pressure-treated pine or cypress lathe or plastic. Although crabbers are
supposed to adhere to stringent regulations regarding size of the trap
entrance (no larger than 10.2 X 16.5 cm, or 4 X 6.5 in) and identification
of their traps and buoys (370.13 Fl. Stat.), they may make other modifica-
tions in the structure of the trap. Each must be permanently marked with
the permit number, and the color of the buoys must be unique and registered
to the permit.

Each crabber either builds his own traps or has them built to his
specifications. Crabbers experiment with the design of their traps and
have found that, in certain areas, crabs will "catch better" with one trap
design than another. In some cases, diligent fishermen have evolved
special trap designs that appear to work better in specific areas year
after year.

In addition to experimentation with trap design, crabbers modify the
usual pattern of setting traps (the trap line). The traditional double
line, spaced 30 to 90 m (100 to 300 ft) apart and running parallel to the
bottom contour, may be modified into a grid, cross, or circular pattern.
Many crabbers contend that "the best catch is where the grass and open
sand meet". Possibly stone crabs find good natural feeding at the seagrass-
sand junction, or merely move from their burrows to the edge of the seagrass
flat and parallel to it, rather than out onto the sand. Some fishermen
believe that they move to the sand to feed.

Traps are baited with trash fish and fish remnants obtained from
charter boats, fish houses, or other fishermen. Fishermen have also ex-
perimented with rawhide and petfood, but most believe that fish works best,
particularly the tough meat of cartilaginous fishes. From 0.5 to 1.5 kg
(1 to 3 lb) of bait are used per trap. The bait may be simply thrown in
the bottom, hung from the top, or set in a bait container. Depending on
the method and amount used, the bait will usually last from 2 or 3 days
to 2 or 3 weeks. Traps are pulled by small boat operators every few days,











Figure 9. Standard Stone Crab Trap And Bouy.


- 7'; '

$ *- I


-i


SI


1+


*rk^


I

Iji t.




i'


/


A-'-


*


'I
A


E
t,

I -


--~-


--- .,-


-_ .. .








weather permitting; large boat fishermen pull their trap lines every
10 days to 21 days.

Crabbing Operations in the Everglades-Florida B Region. Fishermen
have developed an efficient process for stone crabbing. Because the claws
must be cooked before they are chilled, stone crabbing is nearly always
a one-day excursion. Two modifications of a basic method exist.

Large operations (diesel powered boats with large open aft decks and
measuring about 10 to 15 m (33 to 50 ft) in length usually utilize a three-
man team--two mates, or pullers, and a captain. The captain approaches the
trap buoy in such a manner as to avoid entangling the boat propeller in the
buoy line. The mates, stationed in the port aft section of the boat, catch
the buoy line and haul the attached trap aboard, aided by a special auto-
mated winch (Figure 10). The crabs are removed and tossed into wooden
bait boxes. Traps are rebaited, repaired, and tossed overboard in a sin-
gle quick operation. The captain, in the interim, has been maneuvering to
the next buoy in the trap line so that the mates are situated above a new
trap by the time they have finished with the previous one. The crabs are
kept on board until all traps have been pulled. The pullers then declaw the
crabs as the captain is returning to dockside. Claws are removed by grasps
ing them firmly from the rear (Figure lla) and twisting downward or upward
with a swift snapping motion (Figure lib).

Large operation stone crabbers usually dock their boats free-of-
charge at.a fish processing house. In addition, the fish house provides
the crab boat owner with some storage and maintenance facilities for his
traps and boat. In exchange, the fisherman is expected to sell his catch
to the processing house at the price it is offering and purchase bait and
gasoline there. The processor cooks, grades, and sells the claws to
wholesalers or retailers. The Florida Department of Natural Resources (DNR)
and Department of Agricultural and Consumer Services regulates processing
and issues licenses for these sea food dealers (Prochaska and Baarda, 1975).
Grading of the claws is somewhat subjective and varies greatly among dealers.
Generally, claws are separated into weight categories. Claw weights range
from less then 71 g (2.5 oz) to greater than 198.5 g (7 oz) and reach max-
imums of nearly 454 g (1 lb) per claw.

Traps are fished with the three-man system at a rate ranging from
about 25 to 100 traps per hour, depending primarily on weather conditions,
tides, smoothness of the operation, and condition of the equipment and
personnel. Sixty traps per hour is considered a good average speed. From
300 to 700 traps per day are pulled. Many crabbers prefer to set 400 traps
per line. They maintain that efficiency of the equipment and personnel
is maximal when pulling 400 traps per day. These crabbers ordinarily set
out from 1,500.to 5,000 or 6,000 traps per season.

Fishermen operating boats of approximately 9 m (30 ft) in length or
less fall into a different category. These boats are ordinarily run by
one man, who functions as both captain and puller. Sometimes an additional
person, usually a family member, will be employed to assist. A diesel or
outboard powered open boat, which may or may not be equipped with a winch in
the stern, is used. Pulling either by hand or with the winch, the single
crabber follows the same procedure as the three-man team, except that his









Figure 10. Trap Lift And Automated Winch For Stone Crab Traps.


2' ;




I I'- i
"*' --- r






Figure 11. Correct Method Of Breaking Stone Crab Claws.

a. Grasping the crab prior to snapping the claws (taken
from Savage, et al., 1975).


I


b. Snapping the claws with a swift twisting motion.


- .4


jr

- 0


-~


Pool








boat cannot be advanced to the next trap until he has finished working
with the trap he has pulled.

The single crabber can pull up to 50 or 60 traps per hour. The num-
ber 3f traps pulled per day ranges from 25 or less to 300. The number of
traps set out in a season varies greatly and may be less than 50 or as
many as 1,500.

Declawing procedure varies with the single-man crabber. Some will
break off the claws as the traps are pulled, either throwing the crab
back in the water at that time or keeping the declawed crabs on board to
move them away from the area of his trap lines. Others follow the same
procedure as large boat fishermen, tossing the crabs into wooden boxes
until they are returning to, or have reached, dockside and declawing there.
Individuals fishing ENP-waters who are required to keep the whole crab on
board until out of national park waters either declaw the crabs at sea
after leaving the area of national park jurisdiction or upon reaching the
dock.

Single man crabbers use a variety of methods in preparing and selling
the claws. The crabber may cook his own claws. He then freezes them until
he hits a sizeable amount to market or sells them fresh (unfrozen). He may
sell the catch to either a fish processing house or a retail market or
rest urant. Or, he may simply sell his catch to the processor directly,
similar to large boat fishermen.

4.4. Ecologically Sound Fishing Methods

Methods used by stone crab fishermen are designed for economy and
expediency. In general, they attempt to employ techniques that also help
perpetuate the fishery without sacrificing efficiency. In the stone crab
fishery, where the organism can potentially return to the fishery, fisher-
men are concerned with both survival of the population in general and of
the harvested population after declawing. For this reason, a number of
procedures have been adapted by some fishermen that, if used by all fisher
men could contribute significantly to the quantity of crabs "recycled" back
into the fishery.

Gravid Females Are Not Declawed. Females are voracious eaters (Noe,
1967), probably because a tremendous amount of energy is necessary for the
production of their vast numbers of eggs. Declawing gravid females nay put
an additional strain on the crab's metabolic processes and adversely affect
behavior. Declawed gravid females do not care for their eggs for a period
of time following declawing (Schleider, in press). Gravid females have
been observed to drop their sponges after prolonged exposure to air and/or
declawing (Schleider, in press; C. Brown, C. Brown Fish Company, pers. comma;
T.M. Bert, pers. obsn). If gravid females are declawed, some fishermen
throw them immediately back into the water.

Declawing gravid females may reduce their reproductive effort for the
rema:.nder of the season. Food requirements appear to be especially large
during reproductive season (Noe, 1967). Shellfish that normally compose
theii principal dietary constituent would no longer be easily obtainable,
possibly resulting in a lower protein ratio in their diet. Available energy
could be directed into growth of new claws, leaving little for reproduction.








Crabs Are Declawed And Thrown Immediately Back Into The Water. Today
this is apparently done only in the single man operation. Despite the vio-
lation of state regulation on the possession of whole crabs (370.13 Fl.
Stat.), many crabbers hold the crabs until they are able to move away from
the area of their traps or until the end of the day. The density of traps
throughout the fishery renders this endeavor futile in most cases because,
as one crabber said,"At the same time I'm dumping my crabs in another guy's
trap line, he's dumping his :rabs in with mine." Aside from the futility
of moving the crabs, their survival chances may be significantly lowered
if they are thrown en mass into a less favorable environment. Schleider
(in press) recently found that a stone crab's chances of survival after de-
clawing decrease significantly with increased exposure to air prior to de-
clawing. This problem is also encountered daily by ENP fishermen due to
conflicting Florida and national park laws. This point will be dealt with
in detail later.

Canopies Are Built Over-The Stern Of Large Boats. Large operation
fishermen contend that they cannot operate efficiently if crabs are declawed
and immediately thrown back iAto the water. Wooden canopies built over
the sterns of their large boats serve several purposes, one of which is to
keep direct sunlight from the pullers and the catch until it is declawed.
Stone crabs are known to be able to withstand 13 hours of anaerobic condi-
tions while submerged (Karandeyeva and Slva.,,1973),; survival time out of water
has recently been studied (Schleider, in press), and may be considerably lower.
Although canopies are of some assistance, it would be adivsable to consider
incorporating holding tanks on large boats. Immersion in water would probab-
ly reduce the amount of movement (and thus pinching and crushing) of the
closely packed crabs while on deck, since they would not be attempting to
reach water.

Crab Claws Are Measured Before Breaking If Their Size Is Legally
Questionable. This is easily accomplished by attaching a measure to the
stern of the boat where the pullers are working. In this way, sublegal
claws are not wasted.

Biodegradable Traps Are Still Used By The Vast Majority Of Crabbers.
Wooden traps will eventually break down and become habitats if they are
lost at sea. Plastic traps, without at least one easily breakable section,
become death traps indefinitely for stone crabs if the traps are lost. Many
crabs can be lost to the population and market this way.

An Effort Is Made To Teach Mates The Correct Method Of Breaking Claws.
A claw that is broken leaving a fracture wound greater than 14 mm (0.5 in),
or a claw not broken along its natural fracture line, stands a greater chance of
not healing (Davis, et aIl. in-prep.) (Figures 12 and 13). "The crab will -usually
bleed to death. Mortality rates from incorrectly breaking claws are extreme-
ly variable and can be quite high (J.R. Sullivan, DNR, pers. comm.). The
senior writer noted a range from 3% mortality due to incorrect breakage
of claws to a high of 75% in her field work. Some crabbers concern them-
selves with this matter and attempt to instruct their mates on the correct
manner in which to break claws (Figure 11). However, because of the harsh
and unpleasant nature of pulling traps, there is a great turnover rate
for mates. Consequently, there is general unintentional ignorance of proper
claw removal techniques. This is an especially crucial point when the fish-
ery is based upon such techniques.











Incorrectly Broken Stone Crab Claw; Wound Width Is Greater Than 14 mm (0.5 in).


* t

"2*4?!'


/4 'A


I .


Figure 12.








Figure 13.


Open Wound From Incorrectly Broken Stone Crab Claw. The crab will bleed to death from
this wound.


i~ag~


':'^5:


F


1
ji
I

-e


r95.

^* 4

t r ^ -


FS~'I


~~~~--~TT~'~"i"~~~"~"I


'p~a








Most Crabbers Do Not Put Out Excessive Numbers Of Traps. The amount
of time necessary to catch a profitable number of claws depends on several
factors (abundance of crabs, fishing intensity, weather, length of time the
bait lasts). Determining that time, without leaving traps unattended an
unnecessarily long period of time is economically and ecologically the
most beneficial thing to do. From a conservation standpoint, traps left
unattended for an undue length of time may cause needless waste of crabs.
Fishermen report that once the bait is gone, or if it is inaccessible,
the crabs will feed upon one another. This waste can be substantial, when
multiplied by thousands of traps.


5. UTILIZATION PATTERNS


5.1. Magnitude Of The Fishery

5.1.1. Landings

According to National Marine Fisheries Service (NMFS) statistics
(NMFS, 1954-1978), the stone crab industry is among the ten most important
of the fisheries in Florida (Prochaska, 1976). Following an initial period
of little increase in volume of crabs landed, statewide commercial landings
have continually risen, with only minor setbacks, for the past20 years
(Figure 14). The rate of increase is currently averaging approximately
30% per year.

Florida's east coast contributed significantly to total production
of stone crabs only from 1961 to 1967, when from 12.8 to 25.0 percent of
the total catch came from that region (Savage, et al., 1975). The west
coast has always supplied the vast majority of claws and presently provides
about 98% of the total volume landed. On the average, the E-FB fishing
region has provided 80% of the total west coast amount in recent years.
Monroe and Collier counties together supply 98% of the E-FB landings of
stone crabs. In short, these two counties alone have accounted for over
three-quarters of the stone crabs landed in the entire state since 1966
(Figure 15).

In Monroe county, stone crab landings rank fifth in production below
shrimp, spiny lobster, and Spanish and king mackerel and have been among the
top five fisheries since 1965. Prior to 1965, county landings rose fairly
steadily in relative importance from the 17th position that was held in 1955.

However, landings from Monroe county have not kept pace with either
statewide increases in landings or Collier county landings. With the
exception of 1977, landings have shown relatively little increase since
1966 and almost none since 1968 (Figure 14), although production figures
fluctuate greatly from year to year. When absolute poundage is converted
to percentage of the total pounds landed statewide, it becomes evident
that Monroe county has declined in relative production from a maximum
in 1965 and 1966 (Figure 15). Total production of the E-FB region has
maintained high levels because the increase in proportion of Collier
county landings have offset the decline in Monroe county. The contri-
bution to total pounds of all other counties combined was most signi-
ficant from 1962 to 1965.








Most Crabbers Do Not Put Out Excessive Numbers Of Traps. The amount
of time necessary to catch a profitable number of claws depends on several
factors (abundance of crabs, fishing intensity, weather, length of time the
bait lasts). Determining that time, without leaving traps unattended an
unnecessarily long period of time is economically and ecologically the
most beneficial thing to do. From a conservation standpoint, traps left
unattended for an undue length of time may cause needless waste of crabs.
Fishermen report that once the bait is gone, or if it is inaccessible,
the crabs will feed upon one another. This waste can be substantial, when
multiplied by thousands of traps.


5. UTILIZATION PATTERNS


5.1. Magnitude Of The Fishery

5.1.1. Landings

According to National Marine Fisheries Service (NMFS) statistics
(NMFS, 1954-1978), the stone crab industry is among the ten most important
of the fisheries in Florida (Prochaska, 1976). Following an initial period
of little increase in volume of crabs landed, statewide commercial landings
have continually risen, with only minor setbacks, for the past20 years
(Figure 14). The rate of increase is currently averaging approximately
30% per year.

Florida's east coast contributed significantly to total production
of stone crabs only from 1961 to 1967, when from 12.8 to 25.0 percent of
the total catch came from that region (Savage, et al., 1975). The west
coast has always supplied the vast majority of claws and presently provides
about 98% of the total volume landed. On the average, the E-FB fishing
region has provided 80% of the total west coast amount in recent years.
Monroe and Collier counties together supply 98% of the E-FB landings of
stone crabs. In short, these two counties alone have accounted for over
three-quarters of the stone crabs landed in the entire state since 1966
(Figure 15).

In Monroe county, stone crab landings rank fifth in production below
shrimp, spiny lobster, and Spanish and king mackerel and have been among the
top five fisheries since 1965. Prior to 1965, county landings rose fairly
steadily in relative importance from the 17th position that was held in 1955.

However, landings from Monroe county have not kept pace with either
statewide increases in landings or Collier county landings. With the
exception of 1977, landings have shown relatively little increase since
1966 and almost none since 1968 (Figure 14), although production figures
fluctuate greatly from year to year. When absolute poundage is converted
to percentage of the total pounds landed statewide, it becomes evident
that Monroe county has declined in relative production from a maximum
in 1965 and 1966 (Figure 15). Total production of the E-FB region has
maintained high levels because the increase in proportion of Collier
county landings have offset the decline in Monroe county. The contri-
bution to total pounds of all other counties combined was most signi-
ficant from 1962 to 1965.











Figure 14.


Total Volume Of Stone Crabs (Whole Crab Weight) Landed, 1953-1977, For The State Of
Florida, West Coast Of Florida, Monroe County, and Collier County.
Note: Weight of stone crab claws only is one-half the whole crab weight.


o



C-
o
oC







- t



4o
0



0
O
>f


*15.0
(estimate)

(estimate)



-12.5
o
o
o
0
0


-10.0


CO


7.5


o



5.0 o






.2.5


Year













Figure 15. Percentage Of Statewide Stone Crab Landings Attributable To Monroe And Collier Counties,
1953-1976.




)C ,100



1 I Legend:


Percent
Attributable
To
Collier County













Percent
Attributable
To
Monroe Cpfnty


1955 1960 1965 1970 1975
Year


m
CO
0






44
0
(d





E-4i
4-1
o
0)


0)
U
a)
P4






A monthly breakdown of landings for Monroe and Collier counties
(Tables II and III) shows that seasonal peaks are variable for Monroe
County. In contrast, Collier county exhibits greater stability in its
seasonal peaks. In recent years, they have moved progressively closer
to the beginning of the season. Peak months are currently November through
January. Monroe county's inconsistencies in monthly catch can be attributed
in part to many variables, several of which are:

1. prevailing weather and environmental conditions (probably this is
the most influential factor);

2. recruitment into the fishery of spiny lobster fishermen
when that fishery (or another fishery) becomes less productive
than the stone crab fishery;

3. sporadic fishing by part-time fishermen;

4. less dependence upon the stone crab fishery as the sole or
dominant income source.

It is noteworthy that production levels usually drop in both counties in
April, a month before the season closes. This is due to a variety of occur-
rences which may include:

1. fishermen easing their intensity of fishing;

2. the population becoming "fished out";

3. the crabs not moving into the traps as frequently, for some
biological or environmental reason.

5.1.2. Dockside Values

Prices offered for stone crab claws vary a great deal among local-
ities, regulated by demand and claw size (Savage, et al., 1975). Savage
found a range of $0.25 to $0.86 per pound for whole crabs in one county in
1973. Prices for claws alone are commonly considered to be double the
whole crab price (E. Allen, NMFS, pers. comm.).

The average price per pound for stone crabs was comparatively high
in the early days of the fishery. Prices decreased for a number of years,
until a low of $0.33 per pound was reached in 1963 (Table IV). Yearly
increases in dockside prices have occurred during most years since that
time. From 1965 to 1970, the price increased about 30% over the 1965 price
per pound. A 60% gain over the 1970 price occurred from 1970 to 1975. At
the close of the 1977-1978 season, price per pound had increased 15% over
the 1975 price. Total dockside value of landings from stone crabbing in
Monroe and Collier counties rose at comparable levels until recent years
(Figure 16). Fishermen in Collier county rely far more heavily on crabbing
as a major source of income than do Monroe county fishermen. Monies from the
stone crab fishery account for only 3 to 4% of Monroe county's total fishery
revenue. Collier county, however, obtains from 35 to 40% of its fishery
earnings from the stone crab industry. Statewide, the stone crab fishery
currently contributes only slightly over 2% of the total dockside value
for marine landings.











Monroe County Stone Crab Landings, By Month (1968-1978). KlIpgrap equivalents in parentheses.
(National Marine Fisheries Service Data)


Year Oct. INov. Dec. Jan. jFeb. [Mar. IApr. (May


1968-69


1969-70


1970-71


1971-72


1972-73


1973-74


1974-75


1975-76


1976-77


1977-78


65420
(29439)

38055
(17125)

56697
(25514)

58737
(26432)

42360
(19062)

21654
(97443)

50010
(22504)

57187
(25734)

45515
(20479)

71973
(32388)


77001
(34650)

37106
(39198)

52003
(23401)

47983
(21592)

39702
(17866)

51870
(23341)

67759
(30419)

165482
(74467)

164351
(73958)

155468
(69961)


66933
(30120)

88712
(39920)

07243
(48259)

109193
(49137)

71026
(31962)

76737
(34532)

117943
(53074)

117456
(52855)

110561
(49772)

209553
(94279)


196996
(88748)


71458
(32156)

69169
(31126)

107541
(48393)

142840
(64278)

52517
(23633)

280513
(126231)

84862
(38188)

55168
(24826)


66723
(30025)

68632
(30884)

61981
(27891)

43407
(19533)

80585
(36263)

95127
(42807)

77029
(34663)

130667
(58800)


349728*
(157458)

130096
(58533)


68977
(31640)

85094
(38292)

66797
(30059)

134648
(60592)

36458
(16406)

101008
(45454)

92726
(41727)

158452
(71303)


not yet
available


*Landings For
Note: Values


January-February and March-April,


1976 were combined.


within 10% of the highest value for each season are underlined. October and May values repre-


sent only two weeks of trapping, due to opening and closing of the season.


Table II.


72089
(32440)

86122
(38755)

118175
(53179)

94755
(42640)

88376
(39769)

88874
(39993)

114655
(51595)

184425
(82991)


65022
(29260)

28758
(12941)

18839
(8477)

50277
(22625)

62596
(28168)

30910
(13909)

13742
(6184)

33676
(15154)

78575
(35359)


255160*
(114822)


203017
(91358)


S- -(91358)









Table III.


Collier County Stone Crab Landings, By Month
(National Marine Fisheries Service Data)


(1968-78). Kilogram equivolents in parentheses.


Year Oct. Nov. Dec. Jan. |Feb. IMar. (Apr. May


1968-69


1969-70


1970-71


1971-72


1972-73


1973-74


1974-75


1975-76


1976-77


1977-78


54452
(24508)

11492
(5171)

12728
(5728)

15588
(7015)

32536
(14641)

63687
(28655)

57186
(25734)

64044
(28820)

97544
(54895)

171600
(77220)


I I


249549
(112199)


49438
(22247)

59486
(26769)

93288
(41979)

70974
(31938)

76772
(34547)

140468
(70234)

143656
(64645)

170090
(76540)

144860
(65187)


64728
(29128)

77292
(34781)

102616
(46177)

129160
(58122)

136980
(61641)

143370
(64516)

198506
(89328)

125282
(56377)

127932
(57569)

207973
(93572)


64384
(28973)

94590
(42566)

144644
(51590)

158508
(71329)

126444
(56900)

114290
(51430)

174809
(78664)

149372
(67217)


315598*
(140019)


208938
(94022)


165540
(74493)


77074
(34683)

81412
(36635)

113028
(50863)

178184
(80183)

145988
(65699)

156806
(70562)

138671
(62402)

90036
(40516)


71022
(31960)

93590
(42115)

76526
(34437)

177462
(79858)

112164
(50474)

274572
(123557)

137998
(62099)

56780
(25551)

344344*
(154955)

214836
(96676)


29364
(13214)

67286
(30279)

84790
(38156)

97862
(44038)

L26656
(56995)

111596
(50218)

83682
(37657)

73722
(33197)


67794
(30507)

not yet
available


* Landings for January-February and March-April,


1976 were combined.


Note: Values within 10% of the highest value for each season are underlined. October and May values repre-
sent only two weeks of trapping, due to opening and closing of the season.


4076
(1834)

38258
(17216)

12850
(5782)

17032
(76643)

42514
(19131)

55302
(24885)

18648
(8392)

27996
(12508)


- ---


,


,


, ,












Table IV. Price Per Pound For The Stone Crab (Whole Crab Prices),
1955 to 1977 (National Marine Fisheries Service Statistics).

Price Per Pound1
Year ( 1 lb= 0.45 kg)

1955.......................................$ 0.47
1956........................................ 0.44
1957......................................... 0.37
1958......................................... 0.41
1959............................. .......... 0.37
1960....................... .... ........ ... .......0.36
1961............................... .. .... 0.34
1962....................................... 0.36
1963....................................... 0.33
1964...................................... .. 0.34
1965........................................ 0.40
1966............................. ............ 0.40
1967....................................... 0.49
1968.........................................0.47
1969........................................ 0.55
1970........................................ 0.52
1971.........................................0.50
1972..................... ................... 0.62
1973........................................ 0.68
1974........... ... ..... ..................... 0.73
1975 ......... ............................... 0.83
1976........................................ 0.90
1977......................................... 0.91


The National Marine Fisheries Service computed price per pound, whole
crab, as one-half the price for claws alone.










Figure 16. Total Dockside Value Of Landings From The Stone Crab Fishery For Monroe And Collier
Counties And The State Of Florida, From 1953-1976

Legend:
Entire State

Monroe County- *-*---*

Collier County ***** '**'


25.-----------------------------------1


25.


20


o0
o

; 15






0 J
0
0
H I


Year








5.1.3. Permits

The issuing of permits and licenses protects both the fishermen and
the fish by providing a means of observing the growth and current size of
the fishery. This valuable information aids in determining fishing press-
ure on the organism and, when combined with yearly landings statistics,
illustrates important trends in quantity returned per number of men sup-
ported by the industry.

Analysis of permits obtained for stone crab fishing (Figure 17)
since 1968 reveals the following observations:

1. With the exception of a few brief declines, the number of
permits has grown steadily statewide and in both Monroe and
Collier counties.

2. Statewide, the number of permits has increased 670% in the past
ten years.

3. Monroe county stone crab fishermen have increased by over 300 %
during the same time period.

4. Licensed Collier county crabbers, though only one-third in
number, compared with Monroe county, have increased by about
400% since 1968.

Closer examination of stone crab permits (Table V) shows that:

1. Monroe county averages slightly less than half of the total number
of permits for the state, with yearly values showing a general
decline.

2. The percentage of Collier county permits averages far below that
of Monroe county in relation to the total number but is slowly
and steadily increasing.

3. About three-fourths of the crabbers registered for Monroe
county live in the Upper Keys (Key Vaca through Key Largo).

4. Over an 8 year period, an average of 40%'of those individuals with
permits to land stone crabs in Monroe county have been residents
of other counties, primarily Dade and Collier counties.

5.1.4. Traps

Unfortunately, the only years for which the very important data
regarding the number of traps deployed per permit were required to be re-
ported were 1967 to 1970. During that time, the number of traps per permit
statewide, fell from 451 in the 1967-68 season to 228 in 1968-69 and rose
slightly in 1969-70 to 269. Using information available from fishermen on
the number of traps they currently employ and considering Prochaska's (1976)
finding of a gradual decrease in the number of "casual" fishermen in
general (those earning less than 50% of their income from fishing) since
1958, it would seem reasonable to assume that an average of at least 200
traps are utilized per permit in Monroe county and possibly as many as 400.






Figure 17.


Number Of Stone Crab Permits Issued In The State Of Florida,
Monroe County, And Collier County, 1968-1977.


1968-69 69-70 70-71 71-72 72-73 73-74 74-75 75-76 76-77 77-78
Season



Note: Number of permits for Monroe and Collier counties for the 1972-73
and 1976-77 seasons were not available.












Table V. Stdne Crab Permits, 1968-1975.


Total Number
Permits Issued

317

634

754

901


% of Total No.
Permits Issued
to Monroe County

48

52

40

49


% Monroe Cty.
Permits Issued
from Marathon
to Long Key

86

75

78

72


% Monroe Cty.
Permits Issued
to Out-of-County
Residents-


% of Total No.
Permits Issued
to Collier County


Data not available


1515

1306


1975-76 1731


Year

1968-69

1969-70

1970-71

1971-72

1972-73

1973-74

1974-75


41 14


40 74







Trap Density. The only extensive field survey of trap density to
date (Davis and Skagen, 1977; Davis, et al., 1977) has estimated densities
of 4.8 traps/sq km (12.7 traps/sq mi) in ENP waters in January, 5.3 traps/
sq km (13.8 traps/sq mi) in February, and 3.6 traps/sq km (9.4 traps/sq mi)
in April of 1977.
Counts taken in December and January, 1977, by the senior writer on
field trips for this study averaged 4.7 traps/sq km (12.5 traps/sq mi) in
ENP. The ENP stone crab management area is approximately 542.7 sq km (209.5
sq mi) (Davis and Skagen, 1977). Only about 1.4% of the stone crabbers
with permits for Monroe county also obtained permits to fish in the national
park during the 1975-76 season. Low production levels and the conflicting
Florida and national park regulations are reportedly the factors most in-
fluential in deterring fishermen from park waters.

The E-FB fishing region outside of national park jurisdiction (9310
sq km, or 3590 sq mi) supports at least in part the remainder of the
Monroe county and Collier county fishermen (98.6%). Table VI summarizes
trap density estimates at the projected lower and upper range of traps per
fisherman in Monroe county for the 1975-76 season for this area. Out-of-
county fishermen (fishermen with residences in other counties and permits
for Monroe county) are assumed to have about one-half their traps in waters
fished by Monroe county fishermen (a reasonable assumption, when one con-
siders that many out-of-county fishermen have permits exclusively for Mon-
roe county). Although the projected density values may appear to be high,
actual in-field counts taken in December, 1976, and January, 1977 in two
entirely different areas (off the Shark River basin, water depth 3-6 m
(10-20 ft) and behind Mud Keys, water depth 9-15 m (30-50 ft)) considered
to be outside the area of highest fishing pressure and away from spiny
lobster traps, had trap densities considerably higher than the estimated
value for 400 traps per permit (up to 68.7 traps/sq km, or 178 traps/sq mi).



Table VI. Estimated Trap Density In Area Of E-FB Stone Crab
Fishing Region Utilized By Monroe County Fishermen (Exclusive Of
Everglades National Park Waters--Approximately 520 sq km (200 sq mi)--
And Those Fishermen With Permits To Fish In the Park--25 Permits)
During The 1975-76 Season.
Total Number Of Traps In Area 200 traps/permit 400 traps/permit
In-county fishermen 79,000 158,000
(Residing in Monroe County)

Out-of-county fishermen1 28,000 56,000
(Residing in other counties)

Trap Density
per sq mi 62.9 125.9
per sq km 24.3 48.6

Out-of-county fishermen were assumed to put only 50% of the total
number of traps per permit in waters fished by Monroe county fishermen.








5.2. Management Of The Fishery

Fishery management laws are evolved from a complex process involving
scientific data, pressures by various interest groups, legislation, and
implementation. The management of an open access fishery is not like the
private management of a farm. Thus the management of fisheries falls
largely to governmental bodies which can make and enforce laws controlling
the use of an entire fishery (Prochaska and Baarda, 1975). State regula-
tions pertaining to the stone crab are found in Florida Statutes, Section
370.13 (1975) and Florida Laws, 1973, Chapter 73-28. ENP waters are under
the jurisdiction of the National Park Service (NPS) and therefore are sub-
ject to a separate set of regulations (Code of Federal Regulations, Title
36, Section 7.45).

5.2.1. Stone Crab Regulations

Historically, legal controls over the stone crab fishery have ranged
from total absence of regulation to the imposition of a complete moratorium
on crabbing. Although an inquiry was made, no evidence of management legis-
lation before the 1930's was found. The rapid depletion of inshore stocks
near Key West by the early 1940's (Florida Writer's Program, 1941) re-
portedly prompted a five-year moratorium on crabbing in the late 1940's
and early 1950's. Legislation since that time has varied immensely and,
in some cases, reflects the absence of sound biological data as a founda-
tion for regulation. Among the controls that have changed through the
years are:

1. the harvesting season--currently it is October 15 to May 15, with
a 10 day leeway to set out traps before the season opens and a
five day leeway to pull the traps after the season closes;

2. keeping the whole crab vs. keeping only the claws--only claws
are kept at this time; possession of whole crabs on boats is
illegal, except in ENP, where the entire crab must be kept on
board while in national park waters due to differing state and
national park laws;

3. taking one vs. both claws--both can be taken now;

4. harvesting males only vs. both sexes--presently both sexes may
be declawed except in ENP, where only males are declawed;

5. the harvestable size of the animal--a minimum propodus length of
7.0 cm (2.75 in) is now required by the State of Florida; ENP
requires 10.8 cm (4.25 in) overall claw length--these two rulings
are in accordance, the corresponding whole crab size is the same
for each law;

6. licensing of the operation: at this time, the boats of all fish-
ermen with five or more working traps--those that are in the water--
must obtain a free permit, and only one permit is issued per
boat; each permit is licensed for a county or a number of count-
ies to land claws in those counties; ENP fishermen are required
to obtain an additional permit to fish national park waters;
the permit number must be permanently engraved in both the buoy
and trap;






7. limitations on the number of traps per permit: no restrictions
are currently imposed except in ENP, where a limit 6f'400 :tiap6T
per permit has been set;

8. area restriction: no restrictions on fishing grounds currently
exist except in ENP, where the north half of eastern Florida
Bay and all inshore areas to within 400 m (1312 ft) of the coast
are closed to stone crabbing;

9. trap design: entrance size must be no larger than 10.2 X 16.5
cm (4 X 6 in).

5.2.2. Effectiveness Of The Regulations

Fisheries management regulations frequently must meet the very de-
manding test of political feasibility. This powerful influence can be
seen in certain regulations pertaining to the stone crab fishery. As is
the case with almost any set of rules, some appear very beneficial while
others need to be modified and some new additions incorporated.

Apparently Effective Regulations. Several laws are ecologically
sound in that they protect stocks and allow for successful replenishment
of the resource.

Taking only the claws permits some fraction of the harvested popu-
lation to return to the fishery and, hopefully, to the reproductive pop-
ulation. Since many processing houses accepted only claws prior to creation
of the law, whole crabs were,in any event, declawed at the dock, a process
that left countless clawless crabs in dockside waters.

The legal harvestable size is such that females can reproduce un-
molested for about a year before entering the fishery. Females have an
additional advantage in that their claws attain the legal size at a cara-
pace width 7 mm (0.25 in) larger than males (and therefore at an older age)
(Sullivan, in press).

Licensing with permits allows for some type of monitoring of the size
of the industry. It also provides some indication of the size of each
man's operation.

Apparently Incompletely Effective Regulations. Close examination
of other laws reveals that some modification may contribute more to the
wellbeing of both the organism and the industry. In some instances, no
regulatory program exists where some form may be advisable.

Harvesting Season. Length of the harvesting season presently over-
laps the onset of intensive spawning in Florida by about two months (Fig-
ure 18). Although spawning occurs the year around, the contribution of
winter spawning may be very small. Water temperatures are such that the
larval phase may be greatly prolonged, increasing the chances for larval
mortality through predation. Below 250C (770F), temperature of the water
has been shown to reduce survival rates by 50% or more (Ong and Costlow,
1970). Above 250C, larval survival begins to increase drastically. By
mid-March, temperatures in shallow waters of ENP reach 25 C (T. Schmidt,
NPS, pers. Comm.), considerably shortening larval time in the water column












Figure 18.


Percentage Of Total Trapped Famale Stone Crab Population.
With Eggs, Vy Month, In Florida, From The Cedar Key Region,
Biscayne Bao, And The Lower E-FB Region.


Stone Crab Season Closed


60






I



20


*.. r
A










J F M A M J
Month
Legend:
Biscayne Bay. (Noe, 1967):
Biscayne Bay (Cheung, 1969):--- --
Cedar Key (Bender, 1971) :*.........
Lower Florida Gulf of
Mexico (Sullivan, pers. comm.):--*--







and increasing survival rates. About 25% of the female population is egg
bearing at this time (Figure 18).

Simultaneously with this increase in egg production, fishermen re-
port an increase in percentage of females in the trapped population. Data
from Noe (1967) substantiate this information (Figure 19). Female: male
ratios in his traps were 2:1 in mid-March and increased to 5:1 by mid-May.
Thus the proportion of reproductive females in the harvested population
can potentially be up to nearly 170 for every 1,000 crabs caught in mid-
March and 330 in mid-May.

Another problem arises,involving trapping during the closed season.
Many fishermen report that closed season trapping occurs illegally in the
E-FB region, particularly after the onset of spiny lobster season. Summer-
time trapping not only jeopardizes the reproducing female population but
creates a surplus of claws on the market that drives down prices at the
opening of the season. Fishermen justifiably complain bitterly about this
problem, since opening prices the following fall may be below the last
season's closing prices. The present penalty for crabbing out-of-season is
merely a fine. Obviously this is not strong enough to adequately serve as
a deterrent to poaching.

Harvesting Both Sexes. Where a lack of adequate biological infor-
mation exists, the general approach taken by the authorities has been to
enact conservative laws aimed at insuring the perpetuation of the species
while supporting a limited fishery. The former "male only"law, enforced
by both DNR and NPS until October 15, 1973, embodied this philosophy by
insuring survival of at least 50% of the adult population. Considering
that the stone crab is polygamous and that a single copulation will provide
sperm for a number of spawnings, protection of the female population was
a sensible attempt to conserve a resource subjected to increasing fishing
pressure. Then in 1973, after NPS had announced its intention of adher-
ing to the existing law of taking males only, the Florida law was changed
to permit the taking of claws of both sexes. This change was coincident
with enactment of the Florida "claws only" law, also implemented in 1973.
It was therefore practical from an enforcement point of view, since male
and female claws cannot be distinguished once they are removed from the
animal. The consequence of this unilateral change by the State has un-
fortunately been generally bitter feelings toward the NPS and a great deal
of confusion about the legal technicalities of the conflicting laws.

Surprisingly, no significant increase in the landings can be attrib-
uted to the modified State regulation (Figure 14). Nor did catch per permit
rise (Figure 21), interesting observations in view of the hypothetical 100%
increase in available crabs. This would seem to indicate that either the
previous "male only" law was not enforced, or that the increase in landings
was masked by a natural population decline of stone crabs. Fishermen point
out that adverse circumstances such as red tide outbreaks (Gymnodinium
breve) or unusually cold weather have strong influences on abundance of
stone crabs.

Harvesting Both Claws. There is little doubt that the removal of
both claws severely restricts the selection of accessible food items and
leaves the stone crab far more vulnerable to predation. The importance of
the claws in obtaining sufficient food may be even greater in a gravid
female. The claws also perform an essential role in courtship and mating
















Figure 19'. Percentage Of Female Stone Crabs In Trapped'Population, By
Month, In Biscayne Bay, Florida (from Noe, 1967).



Stone Crab Season Closed
100 -






8 80
4j



Cd

O 60-





>-I
g 40.
<


J F A M J J A S N D
Month






behavior. In their highly ritualized behavioral interactions involving
heirarchial establishment, the manner of movement of the claws is the
dominant visual communication stimulus (Sinclair, 1977). In addition,
crabs may have a terminal (final) molt (Cheung, 1976). If this is true,
then these crabs will have no opportunity to regenerate new claws. Some
of Cheung's terminal molt crabs lived two years after their final molt.
Should these crabs be unable to reproduce, an important constituent of
the reproductive population may be lost. This is particularly important
since larger females have a much greater egg bearing capacity. Finally,
females may have a difficult time regenerating their claws since reproduction
and growth are both maximal in summer and reproduction can inhibit growth
(Cheung, 1969).


6. UTILIZATION POTENTIALS


6.1. Present Trends

6.1.1. Trapping Effort

The following computations are based primarily on information avail-
able to the writers through interviews with fishermen and fish processing
house personnel and personal observations made when accompanying fishermen
on their boats. Monetary estimates were derived by combining catch esti-
mates with.fishery statistics values and personal communications regarding
costs and sales from the fishermen and fish houses in Monroe county. All
values presented are certainly subject to exception and are presented
solely to illustrate generalities in an attempt to encompass a large per-
centage of the various aspects of the industry.

Production. Ideally, the ongoing return on the investment in a
fishery is monitored closely by the statistic "catch per unit effort"
(CPUE). Specific information on the number of traps employed per crabber,
average length of time traps are fished (left in the water) before pulling,
man-hours required, and average weight of the catch is needed to compute
this important economic indicator. CPUE can change dramatically over the
course of a season, as can the cost per unit of output, so these statistics
should be continually evaluated to determine an average and as a notation
on peaks and declines for the season. The data needed to calculate CPUE
and cost per unit of output are not available for the stone crab industry
and substitutions and estimates must be made.

Data gathered from questioning fishermen and observing landings in
December, 1976,-and January, 1977, and from tallies procured by the senior
writer during five trips accompanying stone crabbers in verious areas of
the E-FB fishery during that time period, showed that fishermen utilizing
the three-man operation usually obtain between 34.0 and 96.4 g (1.2 and
3.4 oz) of crab claws per trap-night. The mean for that portion of the
season, as determined using the same sources, was 48.2 to 65.2 g (1.7 to
2.3 oz) per trap-night. When questioned about their average catch five
years ago, every fisherman independently presented figures that reduced to
a catch of about 113.4 g (4 oz) per trap-night. However, many fewer traps
were used by all fishermen at that time. Noe (1967) averaged 136.1 g (4.8
oz) of claws in Biscayne Bay during the 1964-65 season. Bender, in 1971,






behavior. In their highly ritualized behavioral interactions involving
heirarchial establishment, the manner of movement of the claws is the
dominant visual communication stimulus (Sinclair, 1977). In addition,
crabs may have a terminal (final) molt (Cheung, 1976). If this is true,
then these crabs will have no opportunity to regenerate new claws. Some
of Cheung's terminal molt crabs lived two years after their final molt.
Should these crabs be unable to reproduce, an important constituent of
the reproductive population may be lost. This is particularly important
since larger females have a much greater egg bearing capacity. Finally,
females may have a difficult time regenerating their claws since reproduction
and growth are both maximal in summer and reproduction can inhibit growth
(Cheung, 1969).


6. UTILIZATION POTENTIALS


6.1. Present Trends

6.1.1. Trapping Effort

The following computations are based primarily on information avail-
able to the writers through interviews with fishermen and fish processing
house personnel and personal observations made when accompanying fishermen
on their boats. Monetary estimates were derived by combining catch esti-
mates with.fishery statistics values and personal communications regarding
costs and sales from the fishermen and fish houses in Monroe county. All
values presented are certainly subject to exception and are presented
solely to illustrate generalities in an attempt to encompass a large per-
centage of the various aspects of the industry.

Production. Ideally, the ongoing return on the investment in a
fishery is monitored closely by the statistic "catch per unit effort"
(CPUE). Specific information on the number of traps employed per crabber,
average length of time traps are fished (left in the water) before pulling,
man-hours required, and average weight of the catch is needed to compute
this important economic indicator. CPUE can change dramatically over the
course of a season, as can the cost per unit of output, so these statistics
should be continually evaluated to determine an average and as a notation
on peaks and declines for the season. The data needed to calculate CPUE
and cost per unit of output are not available for the stone crab industry
and substitutions and estimates must be made.

Data gathered from questioning fishermen and observing landings in
December, 1976,-and January, 1977, and from tallies procured by the senior
writer during five trips accompanying stone crabbers in verious areas of
the E-FB fishery during that time period, showed that fishermen utilizing
the three-man operation usually obtain between 34.0 and 96.4 g (1.2 and
3.4 oz) of crab claws per trap-night. The mean for that portion of the
season, as determined using the same sources, was 48.2 to 65.2 g (1.7 to
2.3 oz) per trap-night. When questioned about their average catch five
years ago, every fisherman independently presented figures that reduced to
a catch of about 113.4 g (4 oz) per trap-night. However, many fewer traps
were used by all fishermen at that time. Noe (1967) averaged 136.1 g (4.8
oz) of claws in Biscayne Bay during the 1964-65 season. Bender, in 1971,








ranged between an estimated 567 g (20 oz) of claws to a minimum of 90.7 g
(3.2 oz)at Cedar Key.

Single-man crabbing operations have a much wider range in catch
weight per trap-night. One crabber has reported a catch of less than a
half kilogram (approximately a pound) of claws per trap over an entire
season while another said he averaged over 85 g (3 oz) per trap-night.
These values are probably extremes. Using the same data base as employed
for the three-man operation, a mean catch of 28.4 to 42.5 (1.0 to 1.5 oz)
of claws per trap-night was estimated. Davis (1976) also reported a CPUE
of 29 g (1 oz) per trap-night in ENP in January of 1975, the result of a
continual decline from 113 g (3.9 oz) since 1972.

Prices. As is the situation with many industries in the country,
maintenance and operating expenses for stone crabbing have increased
steadily in the past few years. Rises in fuel prices account for large
additional expenses despite the availability of certain state and federal
tax exemptions (Cato, 1973). In-depth economic evaluation is not possible
due to lack of information on relative past and present cost and return
relationships. However, simple comparisons of the price of stone crab
claws with important economic indicators (consumer price indices, or CPI's)
can be informative. Although increases in the price paid for stone crab
claws may seem to have been high in recent years, they have not paralleled
average increases in raw produce wholesale prices (Figure 20). This CPI
is the category into which dockside prices of stone crab claws fall. How-
ever, the price of stone crab claws has kept pace with rises in overall
cost of living (for commodities and service groups). In practical terms,
this means the fisherman is maintaining his income level from crabbing
commensurate with the overall cost of living.

Five years ago, the catch per trap-night of all fishermen, regardless
of the size of their operations, was approximately the same (Table VII).
Both size classes of fishing enterprise have seen losses in poundage and
dollars. This is a common market phenomenon associated with increases in
the number of traps per boat. Single-man operations have undergone the
greatest decrease in unit return, with nearly a 40% reduction over the past
five years. (This decline is not nearly so pronounced in the Key West area
as in ENP.) Three-man crabbing operations have experienced only an 8.5%
drop in unit return, probably due to the greater accessibility of less
heavily trapped offshore areas to larger boats. This does not necessarily
mean that crabbing has not been at all profitable. Declines in return per
trap can be offset by increasing the number of traps per boat, rises in
dockside prices, or decreases in cost per unit of output.

In fact, rising prices in dockside values have offset decreases in
the average catch per license (Figures 21 and 22). Both Monroe county and
the entire state have experienced slight increases in return per licensed
fisherman since 1968. Average unit return in Collier county has remained
relatively stable for the past five years, with large fluctuations occurring
from year to year.

6.1.2. Harvesting Pressure

Many natural adaptations enhance the chances of the stone crab for
survival, even under heavy fishing pressure:









Figure 20. Dockside Price Of Stone Crab Claws (Adjusted To Consumer
Price Index) And Important Consumer Price Indices, 1955-1975.
250


Year


Legend:
Price Of Stone
Price Index)
Consumer Price


Crab Claws Per Pound (Adjusted To Consumer

Index By Commodity And Service Groups (All Items)


Wholesale Price Index For Industrial Commodities (Fuels And
Related Products, And Power)
Wholesale Price Index For Crude Materials For Further Process-
ing (Foodstuffs And Feedstuffs)--Includes Dockside Fishery
Landings











Table VII.


Average Estimated.Value Of Claws Produced Per Trap Night For 1-Man And 3-Man Stone Crab
Fishing Operations For The 1970-71 Season And 1975-76 Season.*


1970-71
Size of Operation Dockside Value Approximate Mean Catch Unit Value
($/unit with claws) (unit with claws/trap night) ($/trap night)

kg lb kg lb kg lb

1-man $ 0.47 $ 1.04 0.111 0.247 $ 0.052 $ 0.257

3-man 0.47 1.04 0.113 0.250 0.053 0.260


1975-76

1-man 0.91 2.00 0.035 0.078 0.032 0.156

3-man 0.91 2.00 0.054 0.119 0.049 0.238



*Data from Davis (1976), with permission, and NMFS (1972) and through personal communications.











Figure 21.


Volume Of Stone Crabs Landed Per
Permit Issued, 1968-1975, For The
State Of Florida, Monroe County,
And Collier County.


Figure 22.


Yearly Income From The Stone
Crab Fishery Per Permit Issued,
1968-1975, For The State Of Flor-
ida, Monroe County, And Collier
County.


Legend:

Entire State-

Monroe County-*-*-
SCollier County **....


..

e ete
e


I


S .


o
o
o
C>
6




0
1-'

4


) 3
^-^
5


Legend:

Entire State--

Mpnroe County.-*- .
Collier County -..***
























Approximate
I i--"
*


Approximate


1968-69 69-70 70-71 71-72 72-73 73-74 74-75
Season


1968-69 69-70 70-71 71-72 72-73 73-74 74-75 75-76
Season


o
o
0
2.5

bO


75-76








1. a single male can fertilize a number of females;

2. fertilization needs only to occur once per spawning season;

3. sperm retention through molting has been observed in the female,
obviating the absolute necessity for copulation at every molt
for successful spawning (Cheung, 1968);

4. extremely high fecundity rates, even among sublegal females;

5. reproductive maturity is reached at a size considerably below
that which is economically feasible for harvesting (at least
one year before claws are -marketable size);

6. opportunistic carnivorous feeding behavior augments chances for
finding enough food for survival;

7. large powerful claws and underground burrows serve as a deterrent
to many would-be predators;

8. a planktonic larval strategy provides a good larval dispersion
mechanism;

9. only the claws are sought for meat, and the crab can potentially
survive declawing to reenter the reproductive population.

Other inherent characteristics are apparently not well adapted toward
survival of the species:

1. high predation on larvae owing to their long pelagic existence;

2. high food requirement levels;

3. narrow larval temperature and salinity range for optimum development;

4. simultaneous reproduction and principal growth season in females;

5. sex and size class groupings allowing harvest of predominately
one sex or size class in an area;

6. cannibalistic behavior and food-dependent territoriality (not
necessarily detrimental in itself, but only allows a certain
number of crabs to occupy a given area, which could be a limiting
factor in harvesting);

7. organisms with pelagic larval strategies often exhibit large
yearly population fluctuations (Thorsen, 1949) which may have
significant annual effects on recruitment to the fished population.

These factors and others influence the size of the population available for
harvest.

Harvesting pressure on the stone crab varies greatly throughout Florida,
depending on profitability in relation to other fisheries in the area,







developmental stage of the fishery, and abundance of the resource. Thus
some regions may be overexploited and others underexploited. The geogra-
phy of the E-FB region, abundance of the stone crab population, and
methods of fishing vary so as to permit dividing the E-FB region into thr'e
areas:

1. National Park Area (NP)--from East Cape to Long Key, including
waters adjacent to ENP;

2. Marathon to Cape Romano Area (M-CR)--from Cape Romano to the
Florida Keys (Long Key to Key West), out to the 18 m (60 ft)
depth contour;

3. Deep Water--west of the M-CR Area and beyond the 18 m (60 ft)
contour.

National Park Area. Nearly all quantitative information available
for this area has been gathered within ENP by NPS staff. About 80% of the
waters in this area are within the national park. The rest are immediately
adjacent and possess essentially the same characteristics; thus NPS find-
ings are believed to be applicable to them.

As previously discussed, NPS has recorded a severe and continued
decline in CPUE for the past several years within ENP boundaries. Several
factors may contribute to the decline:

1. movement of the adult population out of the area to mate and/or
spawn without subsequent equivalent replenishment of stocks;

2. recent or ongoing changes in water or substrate quality and food
availability, either in the national park or in recruitment areas,
that are detrimental to one or more phases of the stone crab's
life history;

3. prevention of necessary successful recruitment from outside the
NP area for potentially harvestable stocks;

4. overfishing of males or illegal fishing of females in the national
park to such a degree that an insufficient population remains
for reproduction.

These alternative hypotheses and others are presently being explored in a
comprehensive study of stone crab ecology and of its commercial fishery
in ENP by Gary Davis, Marine Research Biologist for NPS. From preliminary
data it appears that the female population may move out of the national
park area to spawn in the spring. If that is the case, the population
within the park must depend on the movement of some life stages) back
into the area.

Mass movements of a single sex are well documented for the stone crab
(see Section 3.3.4.),.and are thought to be associated with reproduction.
Salinity and temperature fluctuations in national park waters can be large
and dramatic during spawning season (T. Schmidt, NPS, pers. comm.) and
could account for high larval mortality rates, regardless of where spawning
occurs. Small juvenile crabs appear to be absent presently from habitats








they ordinarily occupy in other localities (G. Davis, NPS, pers. comm.).
Thus, the major source of the population occupying the National Park Area
of the E-FB region may be adults that migrate into the area.

Marathon to Cape Romano (M-CR) Area. The most intensive stone crab
fishery in the state is located west of the ENP Area to the 18 m (60 ft)
contour. This area is fished almost exclusively by both Monroe and Collier
counties. Evidence indicates that the impact on the stone crab popula-
tion has apparently not yet been noticeably detrimental, although the fishery
in this area may be near, at, or slightly beyond saturation level:

1. monthly landings in Monroe county fluctuate irregularly, in part
because Monroe county fishermen resort to other fisheries when
landings drop in the stone crab fishery;

2. the percentage increase in Monroe county yearly landings has been
very low since 1970 (5% per year average) despite far greater
rises in permits (15.7% per year average) and traps;

3. Collier county fishermen, who depend strongly upon the industry,
have experienced severe declines in unit catch (Figure 21), in-
dicating that they too are putting in much more effort per unit
of return despite rapid expansion into deeper water areas;

4. fishermen and scientists (Savage, et al.,1975) have reported
that average claw size decreases late in the season, caused in
part by an increase in percentage of females trapped (Noe, 1967)
and in part by depletion of the stock of large-clawed animals
(Sullivan, in press).

On the contrary, monthly landings statistics for Monroe and Collier counties
do not show the large initial catch followed by continual decline as the
season progresses (Tables II and III) that is associated with an overex-
tended resource such as the spiny lobster (Warner, et al., 1977). Pro-
portionally large drops in production do occur at the season's beginning and
end, for which a number of reasons can be suggested:

1. late entry into or early withdrawal of a significant number of
fishermen from the fishery;

2. less inclination or necessity for the crabs to enter traps at
these times for some reason;

3. additional effort into the fishery from spiny lobster fishermen
midway through the season may mask an actual continual decline
in landings until very late in the season.

In combination, the above elements seem to indicate that the majority of
harvestable crabs are being taken each year. Thus far, no pronounced de-
cline in the population has been noted in the M-CR area. Whether the pop-
ulation can sustain the present harvest rate depends on continued success-
ful recruitment each year.

Recruitment, in turn, depends upon reproductive success and adequate
survival of all life stages. Therefore, an understanding of stone crab







population dynamics Is extremely Important to maintenance of the health
of the fishery in the M-CR area. J.R. Sullivan, marine biologist for the
Department of Natural Resources, is attempting to address this topic in a
comprehensive study of the stone crab population in this area. Under his
supervision, 20,000 trapped crabs were tagged from October, 1975, to June,
1976.

Deep Water. Only recently have E-FB fishermen considered placing
traps in water beyond the 18 m (60 ft) contour. The size of fishery the
deep water stone crab could support is not known. Neither qualitative
nor quantitative information exists for population density, age, or size
class structure, or migratory patterns. Among the possible alternatives
are:
1. deep water crabs are a self-sustaining population able to support
a fishery of some finite size;

2. the deep water population depends on recruitment from shallower
water and is not reproductively independent from the shallow
water population;

3. the shallow water crab population depends on deep water recruit-
ment for its supply of crabs;

4. crabs are highly migratory and are successful reproducers through-
out their range so that the extent of the fishing grounds to
deeper water poses no new population management problems.


Thus the deep water inhabitants may or may not be associated with the popu-
lation currently fished by the industry.

6.2. Future Possibilities

Any choice has both good and bad points which should be taken into
consideration. The options pertaining to the direction in which to take
the stone crab fishery are no exception. The alternatives and their
implications are enumerated here.

6.2.1. Continued Escalation of Fishing Pressure

Data are currently insufficient to evaluate the extent of expansion
which the E-FB stone crab fishery will allow. Some scientists and fisher-
men believe that the fishery will support far more traps than are presently
deployed. Based on resource population and profit/investment trends in
the three areas within the E-FB region, prolonged maintenance of the cur-
rent rate of expansion could result in continuation of the present trends:

1. further decreases in the NP area stone crab population, which
may or may not be important to overall yield but could be
ecologically more significant;

2. continued movement of fishermen into deeper water and farther
away from traditional grounds;

3. further decreases in CPUE.








Other, as yet unencountered situations could arise:


1. population declines in the M-CR area similar to those already
seen in the NP area;

2. confrontations and conflicts over offshore grounds with net and
trawl fishermen (mackerel, shrimp, and pompano fishermen);

3. large investments for more seaworthy equipment associated with
S deep water fishing (sturdier traps, bigger boats, onboard crab
claw cookers) without guarantees of equitable returns and pos-
sible substantial losses in both the quantity of the resource
and return on investments.

The movement of a number of fishermen out to deeper water could
alleviate the shallow water pressure somewhat, raising CPUE temporarily.
However, the attraction of a more profitable fishery could draw a consid-
erable number of new entries into the fishery, again lowering CPUE.

6.2.2. Maintenance of Present Fishing Intensity

The current magnitude of fishing pressure on the E-FB region is
such that:

1. NP area is "fished out" early in the season and shows signs
of serious stock depletion (Davis, 1976);

2. the M-CR area fishery is apparently sustaining present fishing
pressure;

3. the Deep Water area may be underutilized.

Conflicting evidence plus a lack of biological and fisheries data make
it impossible to predict the outcome of the impact of sustained fishing
at present rates. Should the fishery stabilize at approximately its pre-
sent level of saturation, the immediate trends could be much the same as
those listed for continued escalation (Section 6.2.1.). However, the
effects would probably be less pronounced and could be curtailed at some
point. It is also possible that optimum or maximum sustained yield (OY
and MSY) has not yet been reached and that landings would continue to rise
resulting in greater returns for the industry. However, MSY (representing
an "average" of the maximum sustainable harvest for a given fishery stock)
is not necessarily coincident with, and often greater than, OY (a complex
concept involving economic, social, and biological factors in determining
the best sustainable yield). In fact, maximum economic efficiency is at a
level of harvest generally conceded to be below MSY (Wallace, 1975). Thus,
further increases in landings would not insure greater profits.

6.2.3. Reduction of Fishing Pressure Intensity

Decreasing the fishing pressure per unit area could produce a situa-
tion that would be analogous to past years. Overall CPUE would be higher
and production in the National Park area could be enhanced, due to in-
creased recruitment or other factors (see Section 6.1.2.). Reduction in-
volves some form of control, with which some fishermen disagree. Reduc-







tion of a fishery through some fo-m of limitation does have the distinct
advantage of the utilization of a data base from former years. From that
background information the effects of a lessening in fishing pressure
can be predicted, whereas the outcome of continued expansion in an unlimited
fishery must be monitored as it occurs. In the stone crab fishery, past
experience has shown that fewer fishermen (and traps) allowed for a greater
catch per trap-night and sustenance of the resource population throughout
its range.

Some Management Options. Management in crabbing industries through-
out North America has taken many forms, some of which could be easily ap-
plied to the Florida stone crab fishery. Regulations in effect in various
states and Canada which could be applicable to the stone crab industry in
Florida are (summarized from Miller, 1976):


1. no females are taken (Alaska--King Crab, Snow Crab; Newfound-
land--East Canada Snow Crab; Washington, Oregon--Dungeness
Crab);

2. no egg-bearing females are taken (Alaska, Washington, Oregon,
California--Dungeness Crab; Delaware, Maryland, Florida,
Texas--Blue Crab);

3. traps must be attended every two weeks (Alaska--Dungeness
Crab);

4. escape holes in traps for sublegal crabs (Alaska--King Crab;
Alaska, Washington, Oregon, California--Dungeness Crab;
Newfoundland--East Canada Snow Crab; Maryland, Florida, Texas-
-Blue Crab;

5. closing of areas to fishing for various reasons (Newfoundland-
-East Canada Snow Crab);

6. fishing excluded in nursery areas (Alaska--King Crab);

7. trap limits per boat (Alaska--King Crab, Snow Crab, Dungeness
Crab; Newfoundland--East Canada Snow Crab; Delaware, Mary-
land--Blue Crab);

8. registration area restricted (Alaska--King Crab, Snow Crab,
Dungeness Crab);

9. limited entry of boats (Newfoundland--East Canada Snow Crab);

10. catch quotas by area (Alaska--King Crab, Snow Crab);

11. overall catch quota (Newfoundland--East Canada Snow Crab);

12. areas reserved for sport fishery (Washington, California--
Dungeness Crab);

13. smaller size limit for sport (Washington, Oregon--Dungeness
Crab);







14. limits on catch, gear type, gear quality for sport (Alaska--
King Crab, Snow Crab; Alaska, Washington, Oregon, California--
Dungeness Crab; Delaware, Maryland, North Carolina, Florida--
Blue Crab);

15. traps may not be set in water shallower that a specified depth
(Maryland--Blue Crab);

16. shrimp trawling, groundfish trawling and scallop dragging are
excluded from good crab fishing areas (AlaskaK-King Crab,
Snow Crab; Oregon--Dungeness Crab);

17. areas of female concentration closed (North Carolina, Texas--
Blue Crab);

18. dredging prohibited when crabs are buried in the sediment
(Maryland, Delaware, North Carolina--Blue Crab);

19. registration of number of traps (Alaska--King Crab, Snow
Crab);

20. reporting fishing area, number of trap lifts, and quantity of
landings (Alaska--King Crab, Snow Crab; Newfoundland--East
Canada Snow Crab).

Additional regulations for limitation of the stone crab fishery that fish-
ermen and scientists have suggested include:

1. trap limiting prorated on investment: fishermen view this as
the fairest method of partitioning the total catch;

2. taking only the crusher claw on both females and males: although
landings would decrease in the first year of enactment of this
regulation, the long-term benefit to the industry in larger claws
(bringing greater prices) and greater crab survival rates (per-
mitting increased return of declawed crabs into the fishery)
would probably easily offset the initial decline (J.R. Sullivan,
DNR, pers. comm.);

3. catch quotas by individual, based on investment or number of
traps: this method would not only enable equitable apportion-
ment of the resource, but would also help limit the overall catch;

4. reduction of the season by one month in spring: the overlap of
the onset of intense spawning in spring and the end of crabbing
season would be eliminated;

5. subsidization or compensation for fishermen obeying catch quotas:
this approach has many economic and social entanglements but
would aid in protecting the resource from overfishing;

6. imposing a permit fee (up to $500 has been suggested) accompanied
by proof that at least 50% of the individual's income is obtained
by fishing;






7. increasing legal claw size: females would be able to reproduce
a greater length of time before entering the fishery.

6.3. Mariculture Possibilities

6.3.1. Review of Research to Date

The mass culturing of economically valuable marine plants and animals
is currently the focus of intensive research throughout the world. The
stone crab has not been excepted in these endeavors. For the past several
years, a number of attempts to raise stone crabs intensively have been under-
taken with varying degrees of success.

Savage and Mc Mahan (1968) conducted a controlled preliminary growth
study with a few small crabs (1.4-33.3 mm CW, or 0.06-1.3 in CW) in a
variety of indoor habitats. A second attempt to raise small crabs was
initiated by Savage (1971b) under somewhat more rigidly controlled environ-
mental surroundings and on a diet of oysters.

Larval rearing has been more intensely investigated (Porter, 1960;
Ong and Costlow, 1970; Yang, 1971, 1972; Mootz and Epifanio, 1974; Yang
and Krantz, 1976) under a wide range of salinity and temperature conditions,
again with widely varying degrees of success. The most comprehensive
survey of salinity and temperature requirements was done by Ong and Costlow
(Table VII). The results available from other researchers are summarized
in the following table (TableVIII)for comparison. All researchers other
than Yang and Krantz listed in these tables utilized a limited number of
larvae and reared them in small indoor containers (watch glasses and finger
bowls). Thus, they were able to monitor the environment more closely than
were Yang and Krantz.

Mootz and Epifanio (1974) analysed the energy requirement for stone
crab larvae raised on brine shrimp (Artemia spp.) nauplii and found that
they can consume up to an average of 91 Artemia per day. Although invert-
ebrates in general only utilize 10-20% of their total energy expenditure on
growth and reproduction (Phillipson, 1966), it has been reported that the
stone crab channels from 45-82% of its assimilated food energy into these
processes throughout its life (Sushenya and Claro, 1973).

Dr. W.T. Yang (RSMAS, University of Miami) is the only researcher to
date to attempt cultivation through successive generations (Yang, 1971,
1972) and mass rearing of the stone crab from egg to marketable adult (Yang
and Krantz, 1976). They presented details on mass culture rearing, includ-
ing complete descriptions of equipment and procedures. Survival rates
produced by their method are summarized in TableIX. Major difficulties they
encountered in culturing crabs were:

1. crab zoeae have relatively restricted water quality requirements
for optimal growth and are highly susceptible to adverse en-
vironmental changes in mass culture procedures;

2. juveniles and adults have poor survival rates due to cannibalism
and aggressive behavior;

3. high food and space requirements make economic feasibility
questionable;










Table VIII. Comparison Of Survival And Developmental Rates At Different Temperatures And Salinities For
Larvae Of M. mercenaria (taken from Ong and Costlow, 1970).
Temperature 20C (q op) 25 C (77oF) 30C ( foF)
Salinity u/0o Salinity 0/0o Salinity ooo
Molt Results .20 25 30 35 40 20 25 30 35 40 20 25 30 35 40

Survival* 0 0 0 0 0 3 22 34 37 19 11 31 36 30 33 '
Meg.
to Mean time (days) 35.3 32.8 32.4 32.9 33.6 22.5 22.2 20.6 20.9 20.5
c.I
Rany' (days) 33-37 31-38 30-35 30-38 31-37 20-24 19-26 18-24 18-24 19-23

Survival 1 11 32 29 32 44 39 40 46 45 32 42 40 43 41
Z.V
to Mean time (days) 42 40.8 38.1 38.5 38.4- 23.9 22.1 21.7 22.1 22.8 15.6 15.1 13.8 .14.3 13.5
Meg.
Range (days) 37-45 35-46 35-44 35-44 22-26 20-27 20-25 20-25.20-27 13-19 13-18 12-19 12-17 12-16

Survival 37 45 46 46 47 46 48 49 49 49 47 50 47 48 48
Z.IV
to Mean time (days) 33.6 29.3 27.4 28.0 28.3 17.2 16.1 15.7 16.2 16.3 12.6 11.8 10.5 11.3 10.5
V
Range (days) 30-37 27-33 25-30 25-33 25-32 16-19 14-19 14-18 14-18 14-19 10-15 10-14 9-12 9-13 9-12

Survival 40 45 46 47 47 46 48 49 50 49 47 50 48 49 48
Z.III
to Mean time (days) 24.7 21.2 19.9 20.0 20.1 12.7 11.8 11.3 11.7 11.8 9.5 8.7 8.0 8.5 8.0
IV
Range (days) 22-30 19-24 18-22 17-22 18-23 12-15 11-14 10-13 10-14 10-14 7-12 7-10 7-10 7-10 7-10

Survival 42 46 48 49 47 47 48 49 50 50 50 50 49 49 50
ZJI1
to Mean time (days) 16.6 14.4 13.3 13.4 13.5 9.2 7.9 7.4 7.9 8.0 6.5 5.8 5.5 5.5 5.3
III
Range (days) 15-19 13-17 12-14 12-16 12-15 8-11 7-9 7-9 7-9 7-10 5-9 5-7 5-7 5-7 5-7

Survival 46 48 50 50 47 47 49 49 50 50 50 50 50 50 50
Z.l
to Mean time (days) 10.4 8.1 7.7 8.0 8.2 5.1 4.5 4.3 4.7 4.8 3.8 3.5 3.2 3.4 3.2
II
Range (days) 8-12 6-10 7-8 7-10 7-9 5-7 4-6 4-5 4-6 4-7 3-5 3-4 3-4 3-5 3-4
*Percr.ntage survival may be obtained by doubling the figures for No. of larvae, as the initial number of larvae in each T-S combination was 50.










Table IX,


Investigator

Porter, 1960


Mootz and
Epifanio,


Summary Of Results From Larval Culture (Egg To First Crab) Of
Costlow, 1970).


1974


Yang and
Krantz, 1976


Growth
Period
(days)

27


28.5

14.5


System

Small scale,
indoor


Small scale,
indoor

Large scale,
outdoor


Food

Artemia
nauplii


Artemia
nauplii

Rotifers, Artemia
nauplii, zoo-
plankton, blended
invertebrate meat


Salinity
Range
(ppt)

27-33



29-31


0-36
(33.7 avg.)


The Stone Crab (excluding Ong and


Temperature
Range
OC OF

27-30 82-86



24-26 74-77


30-32 86-90


Percent
Survival

7-27 (approx.



25 (approx.)


9.2-15


Table X. Survival Rate For Stone Crab Mariculture Encountered By Yang And Krantz, 1976.
Length of Size of Tank Stock Density Percent Survival
Life Stage Observation Metric English Metric English For the Period Cumulative

Egg to Second or 14 days 1800 1 476 gal 2.9/1 11/gal 12.7
Third Crab (approx.) 8.6
8.0/1 30.3/gal 7.6

Second or Third Crab 85 days 1.5 sq m 1.8 sq yd 100/sq m 83.6/sq yd 5.7
to Small Juvenile (bottom surface) 0.65

10 sq m 12 sq yd 100/sq m 83.6/sq yd 8.1
(bottom surface)
Small Juvenile to
Young Adult 307 days 0.4 hec- 1 acre .11/sq m .09/sq yd 20.7 .01
tares


The Stone Crab iexciualng ung and


- -









4. growth, even under somewhat controlled conditions, is extremely
variable, precluding a single harvest period.

Additional problems in stone crab mariculture revealed in other studies
include:

1. difficulties in obtaining viable egg masses from females that
had been raised in the laboratory and mated with laboratory-
raised males (Yang, 1972);

2. second generation males may not be well oriented in courtship
and mating behavior (Yang, 1972);

.3. spawning and molting cannot as yet be selectively induced
(Cheung, 1969);

4. selective breeding for larger claws may not be advantageous for
best survival of the population (Cheung, 1976).


6.3.2. Practicality and Applicability of Stone Crab Mariculture

A number of natural survival adapatations of the stone crab would
indicate that it might be a suitable species for mass culture:

1. high fecundity;

2. efficient food conversion for growth and reproduction;

3. moderate salinity and temperature tolerance;

4. good (although variable) survival rates in controlled environments;

5. opportunistic feeding habits;

6. ease of obtaining eggs;

7. good resistance to anaerobic or oxygen-impoverished water
(Karandeyva and Silva, 1973).

However, the aggressive behavioral characteristics, excessive food re-
quirements, and length of time to reach legal size (about 2 years) pre-
sent difficult problems that must be solved before large scale maricul-
ture of stone crabs would be economically feasible.

Although the rearing of juvenile and adult crabs has proven generally
unsuccessful to date, mass cultivation of larvae holds greater promise.
Serious difficulties remain, however, in maintenance of optimum water
quality, finding cheap high quality food sources, and decreasing mortality
rates. The present-day expense of brine shrimp, the high degree of food
demand, and low optimum stocking densities in culture tanks presently
preclude successful mass larval culture.

A possible utilization of large quantities of artificially cultured
stone crab larvae would be to "seed" areas depleted of adult crabs in an
effort to replenish stocks. Yang and Krantz (1976) believe that:







"larval culture procedures have an important role in providing
stone crabs for natural resource management for rehabilitation
of declining natural fisheries."

The NP area, where natural reconstitution of the population has been un-
successful, would be an ideal area to test this hypothesis.

Unless the mortality rates encountered by Yang and Krantz could be
drastically reduced, even this application would be unfeasible. For ex-
ample, restocking the NP area with 100,000 second crabs (crabs that have
molted once since metamorphosis) would require, at the optimum density
suggested by those investigators, 143 tanks holding 1800 1 (476 gal) each.
At their survival rates, the expected yield would be 7,000 juveniles and
only 140 adults. Survival rates in nature may be somewhat higher than
those Yang and Krantz recorded, if competition for habitat and food is
minimal.'


7. ENVIRONMENTAL NEEDS


7.1. Basic Requirements Of The Animal

7.1.1. For Daily Maintenance

Aside from the myriad practices previously mentioned that would
contribute toward survival of a greater proportion of the harvested popu-
lation (Section 4.4.), some general considerations need to be made regarding
the "needs" of the stone crab--what environment does the species require to
successfully maintain its position in the marine ecosystem. The most
obvious answers to this question lie in the necessary requirements for
the animal's daily maintenance--favorable water quality, enough food, and
suitable habitat.

Favorable Water Quality. Stone crabs are most commonly found in warm
water of moderate to oceanic salinities. Their larvae require these factors
for optimal survival and rapid maturation. Turbidity (the amount of sus-
pended sediment in the water column) does not seem to greatly influence the
selection of habitat by the adult. Of course, many other variables enter
into optimal water quality, such as dissolved gases, nutrients, and pollu-
tants.

Suitable Habitat. Each stone crab life stage has different habitat
requirements. For larvae, clean water of oceanic salinities and free from
chemical and thermal aberrations is conducive to high percentages of larval
survival. Juveniles require protective hiding places and adults inhabit
bottom into which they can burrow.

Sufficient Food. In the words of Powell and Gunter (1968), "Stone
crabs will eat almost anything to keep from starving". The stone crab is
a carnivore with high energy requirements in all growth phases. Oppor-
tunistic feeding habits enhance its ability to meet these requirements.
Preservation of its animal food sources is essential for continuation of
this species, particularly in heavily fished areas. Undisturbed seagrass
and algal beds, with their associated epiphytes and epizoa are necessary,
not only for habitation of the crabs, but as food sources for declawed crabs.







"larval culture procedures have an important role in providing
stone crabs for natural resource management for rehabilitation
of declining natural fisheries."

The NP area, where natural reconstitution of the population has been un-
successful, would be an ideal area to test this hypothesis.

Unless the mortality rates encountered by Yang and Krantz could be
drastically reduced, even this application would be unfeasible. For ex-
ample, restocking the NP area with 100,000 second crabs (crabs that have
molted once since metamorphosis) would require, at the optimum density
suggested by those investigators, 143 tanks holding 1800 1 (476 gal) each.
At their survival rates, the expected yield would be 7,000 juveniles and
only 140 adults. Survival rates in nature may be somewhat higher than
those Yang and Krantz recorded, if competition for habitat and food is
minimal.'


7. ENVIRONMENTAL NEEDS


7.1. Basic Requirements Of The Animal

7.1.1. For Daily Maintenance

Aside from the myriad practices previously mentioned that would
contribute toward survival of a greater proportion of the harvested popu-
lation (Section 4.4.), some general considerations need to be made regarding
the "needs" of the stone crab--what environment does the species require to
successfully maintain its position in the marine ecosystem. The most
obvious answers to this question lie in the necessary requirements for
the animal's daily maintenance--favorable water quality, enough food, and
suitable habitat.

Favorable Water Quality. Stone crabs are most commonly found in warm
water of moderate to oceanic salinities. Their larvae require these factors
for optimal survival and rapid maturation. Turbidity (the amount of sus-
pended sediment in the water column) does not seem to greatly influence the
selection of habitat by the adult. Of course, many other variables enter
into optimal water quality, such as dissolved gases, nutrients, and pollu-
tants.

Suitable Habitat. Each stone crab life stage has different habitat
requirements. For larvae, clean water of oceanic salinities and free from
chemical and thermal aberrations is conducive to high percentages of larval
survival. Juveniles require protective hiding places and adults inhabit
bottom into which they can burrow.

Sufficient Food. In the words of Powell and Gunter (1968), "Stone
crabs will eat almost anything to keep from starving". The stone crab is
a carnivore with high energy requirements in all growth phases. Oppor-
tunistic feeding habits enhance its ability to meet these requirements.
Preservation of its animal food sources is essential for continuation of
this species, particularly in heavily fished areas. Undisturbed seagrass
and algal beds, with their associated epiphytes and epizoa are necessary,
not only for habitation of the crabs, but as food sources for declawed crabs.








7.1.2. For Species Continuation

Succeeding generations of a species can only be maintained if enough
members of each generation are able to survive and successfully reproduce to
enable the following generation to continue the cycle. Involved in the com-
plex cycle are several essential requirements that must be met for its con-
tinuance. Net reproductive potential must maintain levels that keep pace
with natural mortality and fishing pressure. Spawning and juvenile nursery
grounds must be kept intact. Water quality, food sources, and habitat
must be acceptable for survival of the organism. Predation on any life
stage cannot accelerate to excessive degrees. The failure of any one of
these requisites for an extended period of time could result in severe de-
creases in the population with subsequent repercussions to both the ecology
and the fishery.

7.2. Meeting The Requirements

7.2.1. The Problems

In the extensive shallow water tracts of the NP area and Florida's
Gulf of Mexico continental shelf, man can be most influential in shaping
underwater environmental conditions. Almost any major (or a composite of
minor) alteration(s) of coastal wetlands (marshes, swamps, and adjacent
areas) or shallow water coastal bottomland can have far-reaching ecologi-
cal ramifications. This, of course, would most likely have some effect upon
the stone crab population, particularly if the perturbation was done in
areas of enhanced spawning or in nursery grounds.

Bottom Disturbances are of two basic types--dredging and filling,
which displaces large quantities of bottomland within a relatively localized
space, and trawling, which displaces little bottomland but over greater
areas. Dredging and filling for industrial or developmental purposes is
common throughout the Florida coast. They can cause drainage pattern and
inshore current pattern alterations, remove habitat, increase turbidity, and
alter water temperature or salinity. The general ecological ramifications
associated with dredging have been the topic of numerous environmental im-
pact statements.

In south Florida, land development for agricultural, urban, and in-
dustrial uses has threatened the Everglades watershed. For example, one
result of the building of U.S. Highway 1 dividing Blackwater Sound and Barnes
Sound and a mutual demand on fresh water by the national park and various
land practices has been a gradual increase in the salinity of the ENP area
(G. Davis, NPS, pers. comm.). This increase may have affected the stone
crab population in that area directly by altering metabolic or reproductive
processes, or indirectly by providing a suitable environment for predators
that were previously unable to withstand the more estuarine environment,
or eliminating a once abundant food source. Adult stone crabs have an
excellent capacity for withstanding salinity changes (Karandeyva and Silva,
1973) but, although they can survive, they may not be able to reproduce
throughout their salinity range.

The dredging and filling of submerged shallow bottomlands along the
Keys has eliminated tracts of turtle grass flats inhabited by stone crabs,
and increased suspended sediment loads that could adversely affect one or






more life stages of the stone crab or of its food sources. In addition,
the temperature, salinity, or current modifications associated with
dredging and filling could greatly influence survival rates and distribu-
tion of the larvae within the vicinity.

Trawling, primarily for shrimp, is extensively conducted immediately
adjacent to the present principal trapping grounds. Occasionally trawl-
ing fishermen find their best catch within trapping grounds. The amount
and permanency of damage attributable to trawling is not known. Trawling
can level low rocky bottom and overturn small coral heads (D.R. Gregory,
Jr., Florida Sea Grant Prog., pers.comm.). It is reasonable to assume
that it can disturb the bottom inhabited by stone crabs.

Pollutants. Pollutants find their way to the ocean from countless
sources and in a vast array of forms. Two of the more commonly seen types
are discussed here.

Thermal pollution (elevation of water temperature above ambient by
an artificial means) is not an immediate problem in the E-FB fishing
region. However, with the increasing trend toward the utilization of sea
water as a coolant for seaside power and industrial plants, it may soon
become an issue within the region.

Thermal pollution can be a sensitive problem in tropical and subtrop-
ical climates, because most marine organisms live at or near their thermal
limits (Mayer, 1914). Many invertebrates cannot reproduce at temperatures
only 1-20C (2-4 F) above their normal temperature range (Andronikov, 1975).
Sublethal responses (changes in an organism's system that modify its
capacity to grow and/or reproduce) to elevated temperatures can be even
more ecologically significant than direct mortality (Coutant, 1971).

Elevated temperatures can indirectly influence the stone crab by
altering the balance of life around it. Phytoplankton productivity rates
can be increased or decreased by higher temperatures (Gorman and Hopkins,
1974). Because phytoplankton is the base of the food chain, significant
changes in production could have ramifications throughout the food web.

Solid and liquid water pollutants originate from both industrial and
domestic waste products. Pesticides, detergents, metallic compounds,
sewage, and other byproducts are a few examples of this type of pollution.
The addition of these substances to sea water usually initiates a host of
detrimental repercussions. Some of these materials are toxic to marine
life at extremely low concentrations. For instance, chemicals sprayed
for mosquito control near Naples, Florida in 1976 were found to be lethal
to shrimp larvae at 66 parts per trillion or less (EPA, Region IV, Atlanta,
Ga.) and in Monroe county, were alleged to have caused mass mortality of
brine shrimp (Ocean Farming Systems, Inc., vs. Monroe County Mosquito
Control District, Key West Citizen, June 21, 1977).

Studies are presently underway in ENP to determine the degree of in-
trusion of toxic agricultural pesticides into the Everglades estuary and
to marine life. Some problems associated with industrial pollutants are:









1. depletion of oxygen in the water by high concentrations of bac-
teria;

2. lethal or sublethal physiological toxicant-induced abnormali-
ties that can modify growth and reproduction of the stone crab
or its food sources;

3. concentration of toxic substances in the stone crab's tissues,
since the species occupies a relatively high level in the food
chain (stone crabs near Florida's Big Cypress swamp were found
to have approximately 8-12 ppt arsenic in a study conducted
by NPS);

4. stone crab larvae may be far more sensitive to the above situa-
tions than adults.


Overharvesting. Continual harvesting of a marine resource beyond
its MSY for an extended length of time can lead to depletion of that re-
source. The stone crab has several adaptations in its life history to
enable it to withstand strong fishing pressure. The depletion of the NP
area stone crab population and decrease in CPUE elsewhere in the E-FB
region could be interpreted as an indication that pressure may be somewhat
too great. From an industrial and economic standpoint, localized population
depletion due to overharvesting in some areas may not be significant for
overall continual yield. However, the ecological ramifications can be
significant since the stone crab is a voracious carnivore that was once
present in relative abundance in ENP.

7.2.2. The Alternatives

One alternative to the question of environmental quality is to
disregard it. Eventually, however, it must be reckoned with, if the eco-
logical balance and the esthetic beauty of the environment are to be kept,
not to mention the importance of the fisheries that depend upon plentiful
supplies of certain species in the ecosystem.

The undeveloped nature of the lower Florida Gulf coast, the presence
of Everglades National Park, and the environmental awareness of the people
in Monroe and Collier counties have prevented widespread irreparable
damage from industrialization and urbanization in the E-FB region. Pre-
servation of the integrity of the region depends largely on continual
maintenance of an intact and healthy ENP ecosystem, avoidance of large
developmental projects in the Florida Keys that could disturb substantial
tracts of submerged bottomland, and prevention of overexploitation of the
resources of the region. It would be wise for all concerned to closely
monitor the uses of the E-FB coastal zone and bottomland. Sensible pre-
cautions taken now could avoid severe detriment to the ecology and setbacks
in the fisheries later.







8. CONCLUSIONS AND RECOMMENDATIONS


Conclusion 1

The Everglades-Florida Bay stone crab fishery region is relatively
new and does not show signs of severe population depletion. While produc-
tion remains at consistently high levels, some factors that could be inter-
preted as early warning signs of a saturated fishery are beginning to
appear:

1. catch per unit effort is down for all income levels;

2. some traditional fishing areas have shown great reduction
in production levels;

3. fishermen are moving to new areas, despite a lower
profit margin, to maintain production levels.

Conclusion 2

Some evidence indicates that the stone crab population in the Ever-
glades-Florida Bay region (the area between Key West and Cape Romano and
shallower than 18 m or 60 ft) has been harvested at or near its upper
limit of productive potential since about 1970. Fishing pressure varies
in the different areas of the region, such that:

1. The National Park area (East Cape Sable to Long Key) population
is decreasing each year. Superficial and preliminary evidence
indicates that the population may not be completely self sus-
taining, but may depend upon recruitment from adjacent loca-
tions in the Marathon-Cape Romano area. These areas are not
heavily fished.

2. The Marathon-Cape Romano area (Cape Romano to the Florida Keys--
Long Key to Key West--to the 18 m contour) population appears
to be sustaining the current fishing pressure, possibly because
of a high recruitment rate owing to its proximity to a principal
spawning or nursery area, and because part of the population is
protected by National Park Service regulations.

3. The Deep Water area (west of the Marathon-Cape Romano Area and
beyond the 18 m contour) population has not yet been adequately
investigated by either scientists or the industry and may now be
underutilized.

Conclusion 3

High market demand and increasing dockside prices have made stone
crabbing profitable although catch per unit effort has declined in recent
years. In the present situation of a moderately regulated fishery, this
trend will probably continue. Two risks are inherent in the present trend:
a) the resource may become severely depleted before the size of the industry
stabilizes; b) once depleted, it may not recover to its present high rate
of production.








Conclusion 4

Because of rapid growth of the fishery, management strategy has not
kept pace with development of the stone crab fishery. There has been a
steady increase in the number of individuals entering this fishery, and
fishermen report using an increasing number of traps. The resulting in-'
crease in fishing pressure has created the need for a more comprehensive
management plan.

1.-conmmendation A. A comprehensive management plan for the stone
crab fishery in Florida should be developed. Formulation and execution
of the plan will be a highly complex process involving a) research to under-
stand the organism and its interactions with the ecosystem and the fishery;
b) joint user group/management agency decisions on a philosophy of manage-
ment (i.e., who harvests the resource and how much, where, and how to
harvest it); c) joint user group/management agency selection of preferred
management options; d) design and execution of the management plan.

Conclusion 5

While much is currently being accomplished by the National Park
Service and Department of Natural Resources toward understanding the
population dynamics of the stone crab and its response to the impact of
harvesting practices, certain problems should receive immediate attention.

Recommendation A. Research needed: establishment of adult molt
frequency and claw regeneration rates for both males and females by size
class to determine the number of potential harvests available from various
size classes and from each sex. This information would assist in more
accurate determination of the best size class and sex to harvest.

Recommendation B. Research needed: determination of survival rates
and reproduction potentials after exposure to air for various lengths of
time, followed by declawing, for both sexes, and including gravid females.
This would assist in identifying measures needed to avoid waste of har-
vested animals through exposure and subsequent embryonic mortality.

Recommendation C. Research needed: establishment of overall popu-
lation dynauics--including population density and distribution in differ-
ent habitats and throughout the range of the animal, natural survival rates,
migratory patterns, sex or size class aggregations of all life stages, and
identification of spawning and nursery grounds and recruitment areas.
These studies would provide a better understanding of the actual size
of the industry that the resource can support and the population elements
to be protected for restocking.

Recommendation D. Research needed: studies of the deep water stone
crab population for population density and structure, sources) of re-
cruitment, and reproductive success. Since movement of the industry into
deeper water may be imminent, definition of that population is essential
to establish its utilization potential.

Recommendation E. Research needed: investigation of rates of accum-
ulation of pesticide, fertilizer, and industrial process residues, and their
toxicities in various life stages of the stone crab. It is possible that







certain of these compounds may be contributing to the population decline
in the National Park area and may eventually effect the entire Ever-
glades-Florida Bay region.

Recommendation F. Research needed: exploration of potential fish-
eries to ease pressure on the stone crab and augment the industry. The
incidental catch of the spider crab (Mithrax spp.) or Octopus spp. would
be possibilities. Some fishermen have indicated their willingness to
rent their equipment and expertise to scientists for research such as
this. Scientists should avail themselves of this opportunity to become
acquainted with the industry and make use of this practical method of
conducting research.

Recommendation G. Research needed: a study comparing the impact
of removing one vs. both claws of the stone crab. Data from the Depart-
ment of Natural Resources have shown that only 0.4% of tagged stone crabs
that were returned to them had regenerated both claws to legal size within
one year, and these were male crabs only (Sullivan, in press). However,
about 10% of statewide landings are regenerated claws (natural regener-
ation rates are unknown, though)(Savage, et al., 1975). If these data
represent a low return to the fishery, this could effect legislation
in the future. Therefore, this question demands immediate further atten-
tion.

Conclusion 6

One obvious problem in the formulation of a comprehensive manage-
ment strategy is for whom to manage the resource. Traditionally, the
Everglades-Florida Bay stone crab region has provided an income source
for both small operation and large operation commercial fishermen, as
well as provided food and recreation for those individuals who fish
solely for their own needs. Other considerations regarding the use of the
resource and the region itself must be taken into account:

1. extensive tracts of protected, shallow water in the Everglades-
Florida Bay region have lent much toward making the stone crab
industry successful for fishermen operating all sizes of boats
and vessels. Stock depletions in these easily accessible waters
could deal (and in some cases already have delt) an economic
blow to hundreds of small operation fishermen in an area where
the cost of living is very high and the economy fragile;

2. economic indicators may not justify the preservation of the
resource in the National Park area and other depleted local-
ities as most conducive to optimum yield and overall economic
gain;

3. disputes over bottomland used for both trawling and trapping
must be reconciled if the trapping industry is expanded;

4. methods of replenishing or sustaining stocks in traditional
fishing grounds may need to be investigated if it is decided
that they are to be maintained;








5. additional stress may be imposed on other resources also har-
vested by stone crab fishermen (such as the sponges, spiny
lobster, and various fishes and invertebrates) if stone crab
production declines;

6. a few large enterprises may attempt to take over the industry
if limits are set on the fishery.

The various factions utilizing the stone crab resource necessitate
application of the optimum sustained yield approach in formulation of the
management plan.

Conclusion 7

Irrespective of the management strategy chosen, maintenance of the
natural integrity of the Everglades National Park ecosystem should have
highest priority in formulation of the management plan. An intact
Everglades National Park estuary is indispensable to the health of south
Florida's commercial and recreational fisheries. Second and no less
important, there exists a national commitment to protect the ecological
integrity of Everglades National Park. No management strategy should
violate that principle.

Conclusion 8

At this point, the writers wish to reemphasize that the design of
this manuscript is not intended to present mandates for governing the
stone crab fishery nor display partisan views. Decisions regarding
future utilization and management of the fishery should originate from a
user group/management agency association, working toward the best in-
terests of the resource and its fishery. Therefore, of the alternatives
for directing the fishery and protecting the organism discussed through-
out this paper, the writers view the following as the most viable and
impartial interim regulatory measures for the stone crab industry in
Florida, pending the development of a comprehensive management plan.

Recommendation A. Shortening the season by one month in;spring.

1. This represents a compromise in the overlap of the onset of
intensive spawning in Florida and the last two months of the
crabbing season.

2. Reducing the length of the season by one month can potentially
protect up to 3 gravid females for every 10 crabs that would
have been harvested that month.

3. Based on an average of the past five years, the yearly landings
loss to the Everglades-Florida Bay fishery would only be 10%
of the total catch during the initial year that such a regulation
would be in effect. The subsequent contribution to stocks in
succeeding years could offset this loss.








4. Monetarily, the loss is even less than 10%, since the vast
majority of claws taken during the last month are the smaller
female claws. In addition, the market frequently becomes sat-
urated with small claws during this period, driving prices
down further. Finally, if these animals were allowed to grow
over the closed season, their claws would be larger the follow-
ing fall.

Recommendation B. Imposing a permit fee, accompanied by restric-
tions to all wholesale and retail buyers that would only allow them to
buy from licensed fishermen with permits.

1. Fees for permits to fish a specific resource have been shown to
provide a more accurate representation of the actual number of
fishermen utilizing their permits (such as in the Florida spiny
lobster fishery).

2. By reducing the number of individuals who obtained permits and
do not use them, a better estimate of the actual size of the in-
dustry is provided.

3. The monies accrued from licensing should be channeled toward
stone crab biological and fishery research, promotion of stone
crab claws as a Florida seafood delicacy, and better policing
of existing regulations.


Recommendation C. There is a need for fisheries data for the long-
term good of both the fishing industry and the resource. Data collection
has begun on the spiny lobster fishery with the initiation of the keep-
ing of voluntary log books reporting information such as length of time
traps have been left in the water before pulling, number of lobsters
caught, sex of lobsters caught, amount of bait used, location of traps,
date, etc. Information such as this would also be useful for the stone
crab fishery. Whilo individuals in the industry may not be interested
in reporting such detailed information, reporting the number of traps
deployed would be extremely useful. The only true measure of actual
impact on the resource and magnitude of the fishery is the number of traps
being fished. Reports of traps deployed by each licensed fisherman
should be mandatory, held confidential, and immune to prosecution.

Recommendation D. Self-regulation of the commercial fishery. In
lieu of adequate information on the level of harvesting that the resource
will sustain, fishermen should monitor production and catch per unit
effort trends. If a situation develops indicative of significant over-
harvesting before an effective management plan can be deployed, they could
then formulate and impose their own guidelines for control of the resource.
This, in fact, would be the most productive step that could immediately
be taken, in that a few relatively nonrestrictive self-imposed regulations
now may forestall imposition of more severe restrictions necessary in a
few years.









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Fla. Mar. Res. Publ. #13. 37 pp.

Say, T., 1817-18.
An account of the Crustacea of the United States. Jour. Acad.
Nat. Sci., Philadelphia. Vol 1, Part 1 (1817):57-63, 65-80,
97-101, 155-169; Part 2 (1818): 235-253, 313-401, 423-444, pl 4.

Schlieder, R.A., in press.
Effects of desiccation and claw autospasy on hatching success
in stone crabs, Menippe merceneria (Say). Fish. Bull.

Schone, H., 1955.
Zur optischen Lageorientierung (Lichtruckenorientierung")
von swkapoen Krebsen. Naturwiss, 39:552-553.

Schroeder, W.C., 1924.
Fisheries of Key West and the clam industry of southern Florida.
App. II, U.S. Fish. Comm. Rept., 1923. 73 pp.

Sinclair, M.E., 1977.
Agonistic behavior in the stone crab, Menippe mercenaria (Say),
Anim. Behav. 25:193-207.

Sullivan, J.R., 1976.
Annual report for assessment of stone crab (Menippe mercenaria)
survival and population abundance. Prepared for NOAA, Nat.
Mar. Fish. Serv. 25 pp.

Sullivan, J.R., in press.
Studies of the stone crab, Menippe mercenaria (Say, 1819),
in the southwest Florida fishery. Fl. Dept. Nat. Resourc.
Mar. Res. Lab. Publ. No. 00, 1978.








Sushchenya, L.M. and R, Claro, 1973.
Quantitative regularities of feeding and their connection with
the balance of energy of the commercial crab Menippe mercenaria
(Say). Invest. Cent. Amer. Seas. (translated from Russian).
Publ. Smith. Inst. and NSF, by the Fish Resour. Bd., Canada.
pp.312-325.

Tabb, D. C., D.L. DuBrow and R.B. Manning, 1962.
The ecology of northern Florida Bay and adjacent estuaries.
Inst. Mar. Sci., Univ. Miami, Mar. Lab. Tech. Ser. No. 39. 81 pp.

Tebeau, C.W., 1968.
Man in the Everglades. Univ. Miami Press. pp.142-165.

Thorsen, G., 1949.
Reproductive larval ecology of marine bottom invertebrates.
Bio. Rev. 25:1-45.

Wallace, D.H., 1975.
Keynote address. In: Optimum sustainable yield as a concept
in fisheries management. Spec. Publ. No. 9, Amer. Fish. Soc.
pp.5-8.

Warner, R.E., C.L. Combs and D.R. Gregory,Jr., 1977.
Biological studies of the spiny lobster, Panulirus argus
(Decapoda; Palinuridae), in south Florida. Proc. Gulf Carib.
Fish. Inst. 29:153-166.

Wass, M.L., 1955.
The decapod crustaceans of Alligator Harbor and adjacent inshore
areas of northwestern Florida. Quart. Jour. Fla. Acad. Sci.
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Whitten, H.L., H.F. Rosen and J.W. Hedgepeth, 1950.
The invertebrate fauna if Texas coast jetties; a preliminary
survey. Publ. Inst. Mar. Sci., Univ. Texas 1:53-87.

Williams, A.B., 1965.
The decapod crustaceans of the Carolinas. U.S. Fish. Bull.
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Yang, W.T., 1971.
Preliminary report of the culture of the stone crab, Menippe
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Notes on the successful reproduction of stone crabs, Menippe
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"Intensive" culture of the stone crab, Menippe mercenaria.
Univ. Miami Sea Grant Tech. Bull. No. 35. 15 pp.








9.2. FURTHER REFERENCES


Ayers, J.C., 193-.
Relationship of habitat to oxygen consumption by certain estuarine
crabs. Ecol. 19(4):523-527.

Brand, T., 1951.
Anaerobios u bespozvwnochnykh (Anaerobiosis of Invertebrates)
Moscow.

Costlow, J.D., 1965.
Variability in larval stages of the blue crab, Callinectes sapidus.
Biol. Bull. 128(1):68-76.

Costlow, J.D. and C.G. Bookhout, 1959.
The larval development of Callinectes sapidus Rathbun reared in the
laboratory. Biol. Bull. 116:373-396.

Felder, D.L., 1973.
An annotated key to crabs and lobsters (Decapoda, Reptantia)
from coastal waters of the northwestern Gulf of Mexico.
Louisiana St. Univ., Sea Grant Publ. No. 73-02. 103 on.

Gray, I.E., 1957.
A comparative study of the gill area of crabs. Biol. Bull.
112(1):34-42.

Huxley, J.S., 1932.
Problems in Relative Growth. Methuen, London.

Kaestner, A., 1970.
Invertebrate Zoology. Vol. III. Interscience Publ., New York.
523 pp.

Knudsen, J.E., 1959.
Shell formation and growth of the California Xanthid crabs.
Ecol. 40(1):113-115.

Lunz, C.R Jr., 1937.
Xanthidae (mud crabs) of the Carolinas. The Charleston Museum
Leaf. 9:9-27.

Parker, R.H., 1959.
Macro-invertebrate assemblages of central Texas coastal bays
and Laguna Madre. Bull. Amer. Assoc. Pet. Geol. 43:2100-2166.

Pearse, A. S., 1929.
The ecology of certain estuarine crabs at Bearfort, N.C. Journ.
Elisha Mitchell Sci Soc. 44(2):230-237.

Pennak, R.W., 1964.
Collegiate Dictionary of Zoology. The Ronald Press Co. 583.-pp.







Prochaska, F.J., 1973.
The fisherman and the alarm credit system. Fla. Sea Grant Publ.
SUSF-SG-73-004. 9 pp.

Prochaska, F.J. and J.C. Cato, 1974.
Landings, values, and prices in commercial fisheries for the
Florida Keys region. Fla. Sea Grant Publ. SUSF-SG-74-004. 20 pp.

Prochaska, F.J. and J.C. Cato, 1975.
Landings, values, and prices in commercial fisheries for the
Florida west coast. Fla. Sea Grant Publ. SUSF-SG-75-003. 67 pp.

Przibram, H., 1931.
Connecting Laws in Animal Morphology. Univ. Press, London.


Rees, G.H., 1963.
Edible crabs of the United States. Bur.
Leaf. 550. 18 pp.

Ryther, J.H. and W.M. Dunstan, 1971.
Nitrogen, phosphorus, and eutrophication
environment. Science 171:1008-1013.

Schmidt, W., 1949.
Crustations. In: Shelled Creatures and
The Smithsonian Ser. 10:89-247.


Comm. Fish., Fish.



in the coastal marine



Geological History.


Simmone, E.G., 1957.
An ecological survey of the upper Laguna Madre of Texas. Publ.
Inst. Mar. Sci., Univ. Texas, 4(2):156-200.







10. APPENDIX


10.1. Definitions

Abdomen. The posterior portion of the body composed of a group of similar
segments.

Aliquot samples. The division of the total amount into representative
samples of equal parts.

Appendage. Protruding structural part used for locomotion, sensory
reception, feeding, or other purposes; e.g. legs, mouth parts,
tentacles.

Autotomize. To self-amputate, especially with respect to the five pairs
of legs of decapod crustaceans; if such an animal is roughly
handled and seized by a leg, reflex action will break the leg off
across a special breaking joint near its base; during subsequent
molts a normal leg is regenerated.

Basal. Located at the base, or origin.

Biogeography. Study of the geographic distribution of organisms.

Carapace. Dorsal and lateral shield-like plate covering the cephalothorax
(head-thorax) of decapods and certain other crustaceans.

Carnivore. Any animal which is solely or chiefly dependent upon catching
other animals for its food.

Cartilaginous Fishes. (Class Chondrichtyes) Sharks, rays, skates, and
chimaeras; these fishes have skeletons that are without true bone,
but of cartilage only.

Chelate. Pertaining to an appendage modified to form a claw.

Chelicerae. First pair of appendages of Arachnoidea; usually modified for
seizing and crushing.

Crepuscular. Active in dim illumination.

Cuticle. General term for a dead non-cellular organic layer secreted by the
external epithelium of many types of invertebrates, including
arthropods, nematodes, earthworms; the chief functions are support
and protection.

Detritus. Any fine particulate debris of organic or inorganic origin.

Diurnal. Activity by daylight.

Dorsal. The posterior or back surface.

Ecdysis. Periodic shedding or molting of the exoskeleton to permit an in-
crease in size and/or change of form; the.newly exposed exo-
skeleton quickly hardens a size larger than the old one.







Epiphytic. Living on or attached to the surface of a plant, but not
parasitic upon it.

Epizoic. Living on or attached to the surface of an animal, but not
parasitic upon it.

Exopod. Outermost (lateral) branch of typical crustacean appendage;
the structure is often greatly modified in accordance with a
variety of functions.

Fecundity. Relative number of eggs, sperm, or young produced by an animal.

Gonopore. General term for an opening through which eggs and/or sperm are
released.

Gravid. Same as pregnant, but used more commonly, to apply to invertebrates.

Larva. General term for any independent, active, immature stage of an
animal which is morphologically quite unlike the adult.

Lateral. The side; away from the center or midline; the outermost.

Lateral teeth. Protrusions on the side of the carapace.

Mariculture. The artificial culture of marine plants and animals for
increased population.

Maxilliped. Paired thoracic appendage modified for feeding, food handling,
and locomotion.

Metamorphosis. Period of abrupt transformation from one distinctive stage
in the life history to another, such as tadpole to adult frog.

Nauplius. Free-swimming microscopic larval stage.

Niche. Ecological role of a plant or animal with reference to its special
place in its environment; food and nutrition relationships are of
primary importance.

Nocturnal. Activity by night.

Omnivore. Any animal which uses a variety of living and dead plants and
animals in its diet.

Orbit. The depression containing the eyestalk, to which the eye is attached.

Pelagic. Pertaining to the open waters of the sea.

Penes. Male copulatory organs through which sperm are deposited in the
female reproductive tract.

Pereiopod. Paired appendage on most of the thoracic segments of Malacos-
tracans; usually modified for seizing and handling food and for
locomotion.







Phytoplankton. Minute plants that live in the water column and are
incapable of directional movement; thus they are at the mercy
of water currents.

Pleopod. Swimmeret; paired appendage of certain abdominal segments in
many Decapods; by beating back and forth, they create a current
and ensure an.adequate supply of oxygenated water in contact
with the body.

Recruitment. Provided with sufficient new animals needed to correct or
prevent exhaustion; replenishment of the stock.

Rostrum. Pointed process at the anterior end of the head-thorax region.

Sternum. The chief ventral plate of most of the body segments of arthropods.

Stridulation. Production of sounds in some arthropods by rubbing two
modified parts of the body together.

Stridulation organ. Any device for producing sounds by rubbing two parts
together; usually one part is file-like and the other is
scraper-like.

Systematics. The study of the kinds and diversity of organisms and of
their relationships.

Taxonomy. Scientific naming of organisms and their classification with
reference to their precise position in the animal or plant kingdom.

Telson. Broad median projection of the last body segment in many decapod
crustaceans.

Thorax. The central portion of the body between head and abdomen; in
Xanthid crabs, the thorax is fused with the head to form the
cephalothorax.

Trap night. Referring to a day (approximately a 24-hour period) in which
the baited trap has been left in the water to catch fish.

Ventral. The lower surface; underside.

Zooplankton. Minute animals that live in the water column and are incapable
of much directional movement; thus they are at the mercy of water
currents; these forms include larval stages of many large marine
animals as well as small animals that live their entire lives in
the planktonic state.


10.2. List of Acronyms

CL Carapace length.

CPI Consumer price index.

CPUE Catch per unit effort.




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