• TABLE OF CONTENTS
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 Title Page
 Table of Contents
 Introduction
 Economic models for management...
 Selected statistical analyses of...
 National park service spiny lobster...
 Evaluation of methods to monitor...
 Behavior of the spiny lobster,...
 Attractants of the spiny lobster,...
 Biochemical systematics and problems...
 A data management system for the...
 Simple and inexpensive ways to...
 Reproductive potential as a function...
 Florida's programs of data retrieval...
 Population structure of juvenile...
 An economical method of trap fishing...






Group Title: Technical paper / Florida Sea Grant College ;, no. 4
Title: Spiny lobster research review
CITATION PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00072266/00001
 Material Information
Title: Spiny lobster research review proceedings of a conference held December 16, 1976 in Key West, Florida
Series Title: Technical paper Florida Sea Grant College Program
Physical Description: 56 p. : ill. ; 28 cm.
Language: English
Creator: Warner, Richard E
Publisher: State University System of Florida, Sea Grant College Program
Place of Publication: Gainesville
Publication Date: 1978
 Subjects
Subject: Spiny lobsters -- Congresses -- Florida   ( lcsh )
Lobster fisheries -- Congresses -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
conference publication   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Includes bibliographical references.
Statement of Responsibility: compiled and edited by Richard E. Warner ; sponsored by Monroe County Marine Advisory Program.
General Note: Grant 04-7-158-44046.
General Note: "April 1978."
Funding: This collection includes items related to Florida’s environments, ecosystems, and species. It includes the subcollections of Florida Cooperative Fish and Wildlife Research Unit project documents, the Florida Sea Grant technical series, the Florida Geological Survey series, the Howard T. Odum Center for Wetland technical reports, and other entities devoted to the study and preservation of Florida's natural resources.
 Record Information
Bibliographic ID: UF00072266
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 - 000990235
oclc - 09595727
notis - AEW7147

Table of Contents
    Title Page
        Title Page 1
        Title Page 2
    Table of Contents
        Table of Contents 1
        Table of Contents 2
    Introduction
        Page 1
    Economic models for management of Florida's spiny lobster industry, by F. J. Prochaska and J. C. Cato
        Page 2
        Page 3
    Selected statistical analyses of Key West spiny lobster data, by M. C. K. Yang and B. Obert
        Page 4
        Figure 1: Frequency curves with no illegal sale of small lobsters
            Page 5
        Figure 2: Growth curves
            Page 6
        Figure 3: Effect of natural mortality, effect of fishing pressure
            Page 7
    National park service spiny lobster fishery research in Florida: A progress report, by G. E. Davis
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
    Evaluation of methods to monitor recruitment of postlarval Florida spiny lobster, by E. J. Little and G. R. Milano
        Page 13
        Page 14
    Behavior of the spiny lobster, panulirus argus, to baited Florida and prototype traps, by G. C. Miller and D. L. Sutherland
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Figure 1: Glass side view of Florida spiny lobster trap/Figure 2: Glass side view of prototype "bar-room" trap
            Page 20
    Attractants of the spiny lobster, panulirus argus, by B. W. Ache
        Page 21
    Biochemical systematics and problems of larval recruitment in the spiny lobster, panulirus argus, by R. A. Menzies, J. M. Kerrigan, and P. Kanciruk
        Page 22
        Page 23
        Page 24
        Figure 1
            Page 25
        Figure 2
            Page 26
        Figure 3
            Page 27
        Figure 4
            Page 28
        Table 1: Comparison of hypothetical populations/Table 2: Hardy-Weinberg fit of EF4 Locus
            Page 29
        Table 3: EF4 Locus tested for variance correlated with morphometric characteristics and season/Table 4: Population comparisons at the EF4 Locus
            Page 30
    A data management system for the Florida spiny lobster fishery, by D. C. Simmons, J. R. Zuboy, and E. A. Perez
        Page 31
        Page 32
        Page 33
        Figure 1: Conceptual design of the spiny lobster data base
            Page 34
            Page 35
    Simple and inexpensive ways to monitor diving for spiny lobster in the Floida Keys, by C. B. Austin
        Page 36
        Table A: Spiny lobster catches by sport divers, Dade and Monroe Counties, July 20-21, 1975
            Page 37
            Page 38
            Page 39
        Table B: Departure and return times by activity averaged over five Dade County marinas
            Page 40
        Figure 1: Percent departures/Figure 2: Cumulative percent departures
            Page 41
        Table C: Hypothetical observations at 1100 and 1500 hours
            Page 42
            Page 43
    Reproductive potential as a function of female size in panulirus argus, by P. Kanciruk and W. F. Herrnkind
        Page 44
        Page 45
        Figure 1: Size-frequency of all females/Figure 2: Percent of all gravid females vs. size class/Figure 3: Index of reporductive potential vs. carapace length
            Page 46
        Table A: Index of reporductive potential
            Page 47
    Florida's programs of data retrieval and analysis for the spiny lobster fishery, by C. R. Futch
        Page 48
    Population structure of juvenile spiny lobster, panulirus argus, in the Grand Bahama area, by G. T. Waugh
        Page 49
        Page 50
        Page 51
    An economical method of trap fishing for spiny lobster, panulirus argus, in the Bahamas, by G. T. Waugh and H. R. H. Waugh
        Page 52
        Figure 1: Grand Bahama study area
            Page 53
        Figure 2: Method of attaching pop-ups to bouy line/Table A: Capital investment necessary in organizing a one boat (16 ft.) 300 trap spiny lobster fishing unit
            Page 54
        Table B: Cost analysis for a small Bahamian spiny lobster boat fishing 300 traps
            Page 55
        Table C: Summary of actual catch and effort data for March, August, September, October, and November 1976/Table D: Summary of costs and returns for a small boat spiny lobster fishery
            Page 56
Full Text













SPINY LOBSTER RESEARCH REVIEW
PROCEEDINGS OF A CONFERENCE HELD DECEMBER 16, 1976
IN KEY WEST, FLORIDA
Compiled and Edited by
Dr. Richard E. Warner, former Marine Agent and County
Extension Director, Monroe County, Key West, and
Principal Investigator on the project covering the
Biological Studies of The Florida Spiny Lobster.

Sponsored by
Monroe County Marine Advisory Program


Florida Sea Grant


/a/
~s~5~


















SPINY LOBSTER RESEARCH REVIEW
PROCEEDINGS OF A CONFERENCE HELD DECEMBER 16, 1976
IN KEY WEST, FLORIDA

Compiled and Edited by
Dr. Richard E. Warner, former Marine Agent and County
Extension Director, Monroe County, Key West, and
Principal Investigator on the project covering the
Biological Studies of The Florida Spiny Lobster.

Sponsored by
Monroe County Marine Advisory Program









The information contained in this paper was
developed under the auspices of the Florida Sea Grant
College Program, with support from the NOAA Office of
Sea Grant, U.S. Department of Commerce, grant number
04-7-158-44046. This document is a Technical Paper
of the State University System of Florida Sea Grant
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.









Technical Paper No. 4
April, 1978











CONTENTS


INTRODUCTION. .. . .. ...... . . . .

CONTRIBUTED PAPERS AND AUTHORS


Economic Models For Management of Florida's Spiny Lobster
Industry -- F. J. Prochaska and J. C. Cato . .

Selected Statistical Analyses of Key West Spiny Lobster
Data -- M. C. K. Yang and B. Obert . . .
Figure 1 -- Frequency Curves With No Illegal Sale of
Small Lobsters ... . .
Figure 2 -- Growth Curves . .. ..
Figure 3 -- Effect of Natural Mortality, Effect of
Fishing Pressure. . . .

National Park Service Spiny Lobster Fishery Research
In Florida, A Progress Report -- G. C. Davis . .

Evaluation of Methods to Monitor Recruitment of Postlarval
Florida Spiny Lobster -- E. J. Little and G. R. Milano .


. . 2



. . 4

. . 5
. . 6

. . 7



. . 8


. . 13
~2


Behavior of the Spiny Lobster, Panulirus argus, to Baited Florida
and Prototype Traps -- G. C. Miller and D. L. Sutherland .
Figure 1 -- Glass Side View of Florida Spiny Lobster Trap .
Figure 2 -- Glass Side View of Prototype "Bar-room" Trap. .

Attractants of the Spiny Lobster, Panulirus argus
-- B. W. Ache . . . . . .

Biochemical Systematics and Problems of Larval Recruitment In The
Spiny Lobster, Panulirus argus -- R. A. Menzies, J. M. Kerrigan
and P. Kanciruk . . .. . . ..
Figure 1 -. . . . . . . .
Figure 2 -- . . . . . .
Figure 3 -- . . . . . .
Figure 4 -- . . . . . .
Table 1 Comparison of Hypothetical Populations .
Table 2 Hardy-Weinberg Fit of EF4 Locus. . .
Table 3 EF4 Locus Tested For Variance Correlated With
Morphometric Characteristics and Season. .
Table 4 Population Comparisons at the EF4 Locus. .

A Data Management System for the Florida Spiny Lobster Fishery
-- D. C. Simmons, J. R. Zuboy, and E. A. Perez . .
Figure 1 -- Conceptual Design of the Spiny Lobster Data Base.


. 21


. 30
. 30


. 31
. 34














Simple and Inexpensive Ways to Monitor Diving for Spiny Lobster
In the Florida Keys -- C. B. Austin . .. . .
Table A Spiny Lobster Catches By Sport Divers, Dade and
Monroe Counties, July 20 21, 1975 . .
Table B Departure and Return Times By Activity
Averaged Over Five Dade County Marinas . .
Figure 1 -- Percent departures. . . . .
Figure 2 -- Cumulative percent departures . . .
Table C Hypothetical Observations at 1100 and 1500 Hours

Reproductive Potential As A Function of Female Size In
Panulirus argus -- P. Kanciruk and W. F. Herrnkind . .
Figure 1 -- Size-Frequency of all Females . . .
Figure 2 -- Percent of all Gravid Females vs. Size Class. .
Figure 3 -- Index of Reproductive Potential vs. Carapace
Length. . . ... . . ..
Table A Index of Reproductive Potential. . .

Florida's Programs of Data Retrieval and Analysis For The
Spiny Lobster Fishery -- C. R. Futch . . . .

Population Structure of Juvenile Spiny Lobster, Panulirus argus,
In the Grand Bahama Area -- G. T. Waugh. . . .


An Economical Method of Trap Fishing For Spiny Lobster,
Panulirus argus, In the Bahamas -- G. T. Waugh and H.R.H. Waugh.
Figure 1 -- Grand Bahama Study Area . . . .
Figure 2 -- Method of Attaching Pop-ups to Bouy Line .
Table A Capital Investment Necessary In Organizing A
One Boat (16 ft.) 300 Trap Spiny Lobster
Fishing Unit . . . . .
Table B Cost Analysis For A Small Bahamian Spiny
Lobster Boat Fishing 300 Traps . . .
Table C Summary of Actual Catch and Effort Data for
March, August, September, October, and
November 1976. Trap Day (td) is Defined As
One Trap Fishing A 24-Hour Period. . .
Table D Summary of Costs and Returns For a Small Boat
Spiny Lobster Fishery. .. . .


. 36

. 37


. 46
* 47


* 48


* 49


. 52
* 53
S. 54


* 54

* 55



. 56

. 56











INTRODUCTION


The large populations of the spiny lobster (Panulirus argus; family
Palinuridae) in South Florida waters form the basis of the state's second most
valuable commercial fishery, after shrimp. They also support a large and rapidly
growing marine recreational activity. Steadily increasing fishing efforts have
been accompanied by a reduced catch per unit of effort that for many is
unsatisfactorily low. Associated increases in capital outlay, maintenance, and
fuel costs have reduced profits. Questions concerning 1) a further reduction in
minimum size for commercial and sport harvest, 2) age and size for onset of
reproductive activity, 3) optimum age and size for harvesting, and 4) the effects
of limited entry and/or other management practices on the economics and biology
of the resource are asked by user groups with increasing frequency.

Over a period of three years beginning about 1974 there had developed a
significant group of biological and economic research programs on the spiny
lobster populations of South Florida. This included a research project sponsored
by the Florida Sea Grant College Program in an attempt to answer the biological
aspects of the above questions and to promote and facilitate ancillary studies so
that wise management decisions could ultimately be made jointly by user groups
and the relevant management agencies. Economic analysis of effort and yield in
the Florida spiny lobster industry was also funded by Florida Sea Grant.

By the end of 1976 some of these studies had advanced to the point where
important and interesting data had been produced and were available for
dissemination. It was felt that other programs in earlier stages of activity
would materially benefit from greater public awareness of their goals and procedures.

At the same time both the commercial and recreational spiny lobster fisheries
had been reviewing their own needs and plans for the future and in some cases
were drafting legislative proposals. Similarly the Florida Department of Natural
Resources had been engaged in an ongoing review of management practices for the
resource in order to keep abreast of changing use patterns and resource needs.
The various activities were at a point where a thorough and careful assessment
of progress and needs appeared to be fruitful, especially for the research interests
where a comparison of recently obtained field data would facilitate planning of
future research and integration of new findings.

To address these questions the Monroe County Marine Advisory Program
sponsored a conference in December 1976 in Key West. The intensive one-day
meeting devoted itself to a review of recent advances in spiny lobster research
and problems and needs of the spiny lobster fisheries. This report, containing
papers presented at that conference, is published to inform interested persons
of the many aspects of this important Florida marine resource.







ECONOMIC MODELS FOR MANAGEMENT OF FLORIDA'S SPINY LOBSTER INDUSTRY*

Fred J. Prochaska and James C. Catol


Increasing conflicts among spiny lobster fishermen and declining catch
rates and size of lobsters are principal incentives for the research reported
in this paper. The objectives were to provide a means for determining:
1) the maximum economic yield from the fishery; 2) the most efficient allo-
cation of resources within fishery -firms; and 3) the consequences of alterna-
tive management programs on production, costs, and profits. Accomplishment of
these objectives required estimation of three econometric models. Each model
and its use is summarized in the following discussion.

The industry production model in reciprocal form was estimated with mul-
tiple regression techniques. Data pertaining to the.spiny lobster industry in
Monroe County, Florida, for the years 1963 through 1973 provided the basis for
estimation. Industry landings were shown to be significantly related to the
number of traps fished per firm, the number of firms in the industry, and water
temperature. These effort variables explained 80 percent of the variation in
industry landings. Increases in the two effort variables, traps per firm and
number of firms, both produce additional landings in the industry. However, the
marginal increases in landings are declining with additional units of effort.

The decline in catch per additional unit of effort is due to ordinary di-
minishing returns expected in most production processes and possibly due to
negative effects of fishing effort on the biological stock over time, since the
data represent observations over time and no stock variables are included in
the model.

A cost model, which expressed total firm cost as a function of the number
of traps fished per firm and a fixed cost component, was estimated to be in-
corporated with the industry production model to determine maximum economic
yield and optimum resource allocation. The statistical cost model explained 74
percent of the variation in costs of lobster fishing. A stratified sample of
25 Monroe County lobster fishermen was taken to determine production, costs
and revenues in the industry for the 1974 season. These data provided the basis
for estimating the firm cost function. The industry cost model was estimated
as the product of the firm cost function and the number of firms in the industry.

The industry production model, lobster prices and the industry-.cost model
together formed the industry revenue function. Maximization of the net revenue
function with respect to units of effort resulted in a maximum economic yield
estimate of 5.8 million pounds annually which is consistent with landings in
recent seasons. However, an optimum allocation of resources would require
213 firms in the industry each fishing an average of 795 traps. Industry data in
1973 show 399 firms fishing an average of 429 traps each in Monroe County.

Management of the individual fishing firm's operations by the captain
and/or owner of the firm is also a necessity for industry efficiency for any
given level of total industry effort and/or output selected by management


*Abstract of talk presented at the Spiny Lobster Research Conference, Key West,
Florida, December 16, 1976.

1. Food and Resource Economics Dept., University of Florida, Gainesville, Fl.
2







agencies. To provide guidance for efficient firm management a Cobb-Douglas
firm harvest model and cost and returns were estimated from the data collected
in a 1974 survey. Since the data in this model represent one production season
the stock is considered to be fixed. Ninety-three percent of the variation in
landings by individual firms was explained by the number of traps fished per
firm, number of weeks fished, trap pulls per week and craft size. Each of these
factors had positive effects on landings. Optimal levels of each of these fact-
ors depends on associated costs. The optimum level of traps fished per firm is
highly sensitive to increases in lobster prices. This explains at least a part
of the recent expansion in traps fished per firm.

These three models may be used to analyze numerous alternative fishery
management programs, for example, setting a quote on total landings and then
determining an optimum number of traps and firms. Complete discussions of the
models and their usees are found in the following publications.

Williams, Joel S. and Fred J. Prochaska, 1976. The Florida Spiny
Lobster Fishery: Landings, Prices and Resource Productivity.
State University System of Florida Sea Grant Report No. 12,
Gainesville, Florida.

Prochaska, Fred J. and Joel S. Williams, 1976. Economic Analysis of
Cost and Returns in the Spiny Lobster Fishery By Boat and Vessel Size.
Florida Sea Grant Marine Advisory Bulletin, SUSF-SG-76-004.

Prochaska, Fred J., 1976. "An Economic Analysis of Effort and Yield
in the Florida Spiny Lobster Industry with Management Considerations",
in Proceedings: 1st Annual Tropical and Subtropical Fisheries
Conference, Corpus Christi, Texas, Texas A&MUniversity March 1976

Prochaska, Fred J. and Joel S. Williams, 1977. "Maximum Economic
Yield and Resource Allocation in the SpinwyLobster Industryvl_.
Southern Journal of Agricultural Economics, Vol. 9, No. 1, July. 1977.

Williams, Joel S. "An Economic Analysis of Alternative Management
Strategies for the Spiny Lobster Industry", Ph.D. dissertation,
University of Florida, Gainesville, Florida, December 1976.











SELECTED STATISTICAL ANALYSES OF KEY WEST SPINY LOBSTER DATA

Mark C. K. Yang and Bill Obert1


This report is based on data gathered in Key West, Florida, during the
years 1974-1976.

The capability of lobster traps to retain small lobsters used as bait was
analyzed. For one week soak periods, it was found that 933 out of 988 short
lobsters used as bait remained in the same trap. Of nine short lobsters not
used as bait, four returned during a one week soak period to the traps from
which they were originally released. The probability that a short lobster
used as bait would remain in its trap during a one week soak period was shown
to be statistically significantly greater than the probability that a short
lobster not used as bait would return during a one week soak period to the
trap from which it was released.

An analysis of variance (ANOVA) was performed to determine the effect of
using baits (short lobsters) on the catch per trap. Two statistical tests
were performed, one using the total number of lobsters caught per trap as the
dependent variable, and another using the number of legal-size lobsters caught
per trap as the dependent variable. A four way classification ANOVA model was
used in both cases. The classifications were: (i) area (four classes),
(ii) month (seven classes), (iii) soak period (four classes one through
four weeks), and (iv) number of baits used (two classes zero, and one
or more). The results of this analysis showed that both the total catch per
trap, and the legal catch per trap did significantly improve when one or more
short lobsters were used as bait.

Length frequency curves from the beginning of the season and the end of
the season indicated that the total mortality rates of juvenile lobsters and
legal-size lobsters were almost the same (Figure 1). This result suggested
that either there was an illegal juvenile lobster market which was similar
(in numbers of lobsters) to the legal lobster market, or that juvenile lobsters
have a very high mortality rate when put back into the water after capture, or
that both phenomena combined to produce this result.

Data on changes in carapace length between recaptures were used to estimate
growth rate. Assuming that the growth of lobsters follows von Bertalanffy's
model:
= L (l-e-K(t-to)
where t is the carapace length of the animal at age t, and L,, to and K are
three unknown parameters. We have estimated that L~=175 mm. and K=0.111. The
comparison of this result with other lobster studies is given in Figure 2.
This estimation is now subject to modification because we originally thought
that negative growth was not possible, and discarded all the negative growth
data. We have since been informed that a negative growth due to injuries is


1. Department of Statistics, University of Florida, Gainesville, Fl., 32611









possible in lobsters and should be considered in building the growth curve.
With the two estimated parameters L=175 mm. and K-0.111, and the estimated
relationship between weight (W) and length (L),

W = 0.0026L2.7

we found that relative weight increases were greatest for lobsters with
carapace lengths between 70 and 90 mm.

Fishing pressure on the Lower Keys lobster population was also estimated.
The beginning of the season capture rate (no, lobsters/trap day) and the end
of the season capture rate for the 1975-1976 commercial season were used for
this estimation. It was found that the yearly survival rate, (including
natural survival and fishing survival) was 19%, which was larger than Maine's
10% survival rate, but comparable to New Jersey's 20% survival rate (Figure 3).


FREQUENCY CURVES WITH NO ILLEGAL
SALE OF SMALL LOBSTERS


......... End of the Season

Theoretical
-- -- -- Beginning of the Season


X


Carapace Length (am)


0
FIGURE I












Parameters

N.J. Maine Key West


GROWTH CURVES


.20



(L.)
Key West N10
.10 N.J.


Maine


FIGURE 2


50 60 70 80 90 100

Initial Carapace Length (mm)




EFFECT OF NATURAL MORTALITY


L



H
o- L
s '


EFFECT OF FISHING PRESSURE


Parameter of Fishing Pressure


ME

2.30

10%


NJ

1.63

20%


Key West

1.68

19%


VA

1.205

30%


FIGURE 3


-. -


Yield


S- --L


s"
00,
.0









NATIONAL PARK SERVICE SPINY LOBSTER FISHERY RESEARCH IN FLORIDA
A PROGRESS REPORT

Gary E. Davis


SUMMARY

A 1974 Florida Sea Grant meeting identified 13 major problems and
research needs for the Florida spiny lobster fishery. Results and obser-
vations from six years of National Park Service spiny lobster research
which address several of these topics are presented.

Recreational harvest alone effectively reduced a previously unfished
lobster population by 50% in a single season. The average minimum size of
maturity of female spiny lobsters at Dry Tortugas was found to be 80-85 mm
carapace length (CL), significantly larger than previously reported for
Florida, which showed that the current minimum harvest size of 76mm (CL)
does not protect a reproductive stock from exploitation. The natural
average annual mortality of adult lobsters at Dry Tortugas was 23%, and the
total average annual mortality rate was 40%. Tagged juvenile lobsters from
Biscayne Bay migrated into the Keys fishery, all the way to Key West. Adult
lobsters at Dry Tortugas showed virtually no long distance movement over a
three year period. Spaghetti tags (Floy FD-68B) were shed at the rate of
10% per molt by juveniles (35 85 mm CL) in Biscayne Bay. Juvenile lobsters
occupied concrete block shelters in high densities (mean 2.4/block), but
creation of substantially more shelter did not increase the lobster population
in the study area, suggesting that shelter is not the limiting factor on the
juvenile population in Biscayne Bay.

Creation of a nursery sanctuary in Biscayne National Monument was pro-
posed to increase fishery production. Fishery related injuries caused a 40%
reduction in growth rate in an area where over 95% of the lobsters were smaller
than the minimum harvest size. The reduced growth rate could delay recruit-
ment into the fishery by a year or more, increasing mortality prior to reach-
ing legal harvest size. A nursery sanctuary would significantly decrease
injuries to juveniles and hence increase recruitment of young adults into the
fishery. Evaluation of the nursery sanctuary concept would require cooper-
ation of management agencies (both state and federal) and user groups (both
sport and commercial), and should begin soon.

PROGRESS REPORT

Nearly three years ago Florida Sea Grant convened a meeting of scientists
and fishermen at which 13 major problems and/or needs of the Florida spiny
lobster fishery were defined and discussed. At that time declining catch per
unit of fishing effort, maximum sustained yield estimates, limited entry to
the fishery, minimum harvest size of individual lobsters, fishery recruitment,
lobster migratory behavior and patterns, larvae identification, water pollution,
oceanographic conditions affecting larvae dispersal, law enforcement, and in-


1. Everglades National Park, P.O. Box 279, Homestead, Fl., 33030.








adequate fishery statistics were all identified as major problem areas
contributing to economic and biologic stress on the fishery. (Seaman and
Aska, 1974). These are still the problems, but I think we are beginning to get
some answers from our research that allow us to address these problems and
suggest testable management programs to improve the fishery.

The following topics represent a potpourri of results and observations
from the National Park Service lobster research projects which are directly
applicable to fishery management problems: 1) the effects of recreational
harvest on a lobster population; 2) the size of maturity of Florida lobsters;
3) mortality rates of fished and unfished lobster populations; 4) growth
rates and the effects of injuries on growth rates; 5) migratory patterns;
6) effectiveness of spaghetti tags for marking spiny lobsters; and 7) the
use of artificial habitats to increase lobster populations.

The National Park Service manages about one third of the juvenile spiny
lobster habitat in Florida and nearly 100,000 acres of coral reef inhabited
by adult spiny lobsters. Therefore, in addition to the problems identified
in the 1974 Sea Grant meeting, the National Park Service needed to identify
and address the impacts of fishery activities on the natural ecosystems of
the park areas in south Florida.

Three years prior to the 1974 Sea Grant meeting I began an investigation
of the impact of recreational harvest on the lobster population in Fort
Jefferson National Monument at Dry Tortugas, Florida. Briefly, we found a
large, resident population of juvenile and adult lobsters at Dry Tortugas was
reduced by 50% during a single eight month long open season for recreational
fishermen only (Davis, 1977). There was a harvest limit of two lobsters
per person per day enforced. About 22,500 lobsters were caught. The pre-
harvest standing crop was 58.3 kg/ha. As a result of these findings, the cen-
tral core of the Monument (60% of the area) was closed as a sanctuary, and the
remaining area was made available to harvest, subject to State law, for both
recreational and commercial fishermen.

This study also provided considerable biological and fishery data about
fished and unfished spiny lobster populations. For instance, we found that
the average minimum size of mature female Florida lobsters was about 80-85mm
carapace length (CL) at Dry Tortugas. That was nearly 40mm larger than pre-
viously reported for Florida. This may have significant impact on fishery
management strategies since it has been shown that the current minimum size for
legal harvest (76mm) does not protect a reproductive stock (Davis, 1975; and
Kanciruk and Herrnkind, this conference, and 1976). This was one of the
problems specifically identified in the 1974 Sea Grant meeting.

Another major problem partially addressed by data from the Dry Tor-
tugas study is mortality rate. This is an important factor in determining
optimum yields and harvest size for individual lobsters. We found mean annual
mortality rates of 23% for unharvested, 29% for recreational harvested, and
40% for combined recreational and commercial harvested populations of adult
lobsters (ages V to X) .at Dry Tortugas.

Growth rate is another critical parameter needed to formulate fishery








management strategy. We found an average annual growth rate (carapace
length) of 50% for tagged juvenile lobsters in Biscayne Bay. This growth
rate estimate was based on growth measured on 326 lobsters ranging from
35 to 85mm (CL) during periods of 4 to 60 weeks.

We were also interested in the effects of fishing activity on the
lobsters, so we measured the occurrence and extent of injuries on lobsters iii
fished and unfished areas. We found that less than 24% of the 35 to 85mm
(CL) lobsters were missing legs or antennae in an unfished area at Dry Tortu-
gas, whereas in heavily diver-fished Biscayne Bay about 50% of the similar
sized lobsters had sustained such injuries. Furthermore, we found signifi-
cant differences between the growth rates of injured and uninjured lobsters
in Biscayne Bay. The growth rate of injured lobsters was 40% lower than un-
injured lobsters. At the growth rates observed for 326 lobsters, uninjured
lobsters would require two years to grow from 35mm to 85mm (CL), while in-
jured lobsters would take three years. Less than 5% of the lobsters caught
in the Bay during this study were of legal larvest size, and even fewer were
of reproductive size. If not injured by fishing activity, these juveniles
would grow faster and enter the fishery a year sooner, thereby reducing their
mortality prior to recruitment into the fishery.

The information we collected from tagged lobsters on migration showed
that Biscayne Bay is a nursery of the Keys fishery. Lobsters tagged at the
Elliott Key Marina, in southeastern Biscayne Bay, were recaptured moving
through Caesar's Creek, on patch reefs east of Old Rhodes Key, on the outer
reef to depths of 180 feet off of Islamorada, and as far south as Woman Key
near Key West. Many of these movements took place in less than six months.
This is in stark contrast to the lack of movement we observed at Dry Tortugas.
I think this was just a reflection of the migratory nature of juveniles and
the residential nature of adults.

We recently addressed a subject that is crucial to estimates of pop-
ulation dynamics based on tag returns. That is the rate of tag loss. We
double marked 1,250 lobsters with holes punched in their tails and spaghetti
tags (Floy FD-68B). Then we recaptured a portion of the marked lobsters
every month for nine months. Monthly tag losses ranged from 1.9% to 11.1%,
but were generally about 4%. Total tag loss after nine months was 30%.
Most tag losses were apparently associated with molting, so molting frequency
was important for understanding tag loss. Growth data showed that 30% of
the lobsters molted during each of the first three months of the study, so
that after three months 90% of the lobsters had molted. This molting fre-
quency was apparently maintained throughout the study period as well. There
were 117 lobsters recaptured at regular intervals over an extended time and
they averaged 13.4 weeks between molts. Additionally, the ratio of long
term growth (8-9 months) to single molt growth was about three to one,
supporting an intermolt period of thirteen weeks. It was clear that juvenile
lobsters in Biscayne Bay from 35 to 85 mm (CL) molted four times a year with
tag losses of 10% per molt.

One last topic merits review here. At various times the idea of increas-
ing fishery production by enhancing some possible limiting factor, such as
shelter, has been suggested for lobsters (Felik, 1974). At the Elliott Key








Marina we tested this idea by creating a lobster "ghetto" with concrete
block shelters adjacent to an established population center. Over the past
seven months there was regular movement of lobsters through the area. Young
lobsters, (35mm CL) entered the area, and older lobsters (75 85 mm CL)
left to enter the fishery offshore so there was ample opportunity for an in-
creased population to be established. Lobsters occupied the new shelters at
high densities, but the population in the adjacent marine declined at nearly
the same rate as the "ghetto" population increased, so there was no net in-
crease in the lobster population of the area. This suggested that while
juvenile lobsters may be found to occupy nearly every available shelter in
the Bay in high densities (when protected from fishing activity), shelter
may not be the limiting factor on juvenile Spiny Lobsters in south Florida.

In conclusion, I would like to suggest a testable management experiment
that could significantly improve the lobster fishery's production. Our pre-
liminary studies showed that 95% of the lobsters we caught in Biscayne
Bay were under legal size immature juveniles and that half of these
juveniles had sustained injuries, many from fishing activity, that reduced
their growth rate by 40%. This may cause injured lobsters to stay in the
Bay an additional year or more, thereby increasing their mortality prior to
entering the fishery offshore and to the south in the Keys. If the southern
half of the Bay wereclosed to all lobster fishing, these injuries would be
significantly reduced. The 5% legal sized lobsters in the Bay would soon
migrate into the fished area and would not be lost from the fishery. The
subsequent increase in growth rate and decrease in mortality rate in the Bay
should produce a measurable increase in lobster fishery production within
two seasons. By closing the southern portion of the Bay that is within the
boundaries of Biscayne National Monument, an existing management unit is
utilized which is already designated on navigational charts and recognized
by the public and commercial fishermen. There is also an established data
base for the lobster population in the Monument and an ongoing research pro-
gram to evaluate changes. Additionally, supplemental law enforcement pro-
tection from park rangers is available in the Monument to ensure an effective
sanctuary.

To evaluate the effectiveness of the nursery sanctuary, some accurate
and precise measure of fishery production must be developed and implemented
to measure production before and after closure of the proposed sanctuary.
The National Park Service is developing a fishery monitoring program in
Biscayne National Monument. It will be compatible with the commercial log
book system being developed by the National Marine Fisheries Service for
the entire lobster fishery. A similar recreational fishery monitoring program
is needed outside the Monument to supplement the commercial log book system.
Implementation of these programs already has high priority in the develop-
ment of alternative fishery management strategies. I suggest that evaluation
of a nursery sanctuary would be an excellent demonstration of the value of
the good fishery statistics these programs could provide with the cooperation
of the fishermen. This fishery needs improvement. A nursery sanctuary
could help it. It is time to get the management agencies and the user groups
together and test the concept.








LITERATURE CITED


Davis, Gary E., 1975. Minimum size of mature spiny lobsters, Panulirus
argus, at Dry Tortugas, Florida. Trans. Amer. Fish. Soc. 104(4):
675-676.

Davis, Gary E., 1977. Effects of recreational harvest on a spiny
lobster, Panulirus argus, population. Bull. Mar. Sci. 27(2):223-236.

Felik, Robert, 1974. Florida spiny lobster industry problems. In:
Research and information needs of the Florida spiny lobster fishery.
Seaman and Aska. Eds. Florida Sea Grant Publication 74-201, pp. 10-14.

Kanciruk, P. and W. F. Herrnkind, 1976. Autumnal reproduction in Panulirus
argus at Bimini, Bahamas. Bull. Mar. Sci. 26(4): 417-432.

Seaman, William, Jr. and Donald Y. Aska, 1974. Research and information
needs of the Florida spiny lobster fishery. Florida Sea Grant
Publication 74-201. 64 pp.









EVALUATION OF METHODS TO MONITOR RECRUITMENT
OF POSTLARVAL FLORIDA SPINY LOBSTER

Edward J. Little and Gary R. Milano


Despite the considerable importance of the Florida fishery for Spiny
Lobsters, Panulirus argus, comparatively little is known of the manner by
which populations are replenished. The larvae are thought to drift up from
the Caribbean before metamorphosing into transparent postlarvae. The latter
swim or are transported to nursery grounds, suspected to exist primarily in
nearshore shallows, where they enter benthic juvenile lobster populations.
Management of the fishery resource requires more information than presently
available on times and places of recruitment, factors influencing the process,
and relationships between recruitment success and subsequent fishery product-
ivity.

The Florida Department of Natural Resources Marine Research Laboratory,
funded through a research grant from Public Law 88-309 administered through
National Marine Fisheries Service, is studying methods to measure fluctuations
in postlarval lobster recruitment. Recruitment is assessed by counting post-
larvae that have sought shelter in Witham habitats, artificial substrates
that mimic natural fouling communities frequented by newly recruited postlarvae.
Each habitat consists of a series of eight to sixteen rectangular thin sheets
of a soft material composed of thousands of intertwined vinyl filaments, the
sheets being suspended vertically beneath a two foot square plywood and
polyurethane foam raft. Virtues of the device are simplicity, low cost,
durability, ability to operate while unattended, and, as shown in several
years of preliminary studies, proven attractiveness to postlarval lobsters.
A unique feature of this recruitment quantification tool is also the ease by
which even an untrained observer can count and remove postlarvae.

In our study, begun in February, 1976, we measure daily settlement of
postlarval lobsters and associated organisms to groups of nine Witham habitats
1.0 2.0 m apart in waters 1.0 m deep at each of three sites 100 200 m off
the south shore of Boca Chica Key, Florida Keys. Similar sampling off Sugar-
loaf Beach, approximately 15 km east of Boca Chica, was begun in June, 1976.
Through such efforts we hope to obtain data on temporal and geographic
variations in postlarval lobster abundance and to see what techniques produce
catches most indicative of natural recruitment intensity.

Although the study has been underway for less than a year, a few trends
are already evident. Recruitment may occur throughout each month, but only
catches during the new moon through first quarter period are large enough to
be useful in recruitment analysis. Habitats must have at least two months
continuous service before becoming reliable collectors of postlarvae; those
with shorter exposure periods catch few postlarvae, presumably because fouling
assemblages attractive to postlarvae have not developed sufficiently.
Furthermore, not all sites are equally conducive to postlarvae settlement.
Sites located over rocky bottoms with good water exchange have been so much
more consistently productive than other sites that we intend to study this
phenomenon more fully in the future.


1. Florida Department of Natural Resources, Key West Field Laboratory








In the two remaining years of our project, we plan to continue monitoring
recruitment patterns, develop more effective habitats, and identify types of
localities where habitats can be deployed for maximum productivity. Our
work will hopefully provide techniques for assessing recruitment to lobster
nurseries, enhance understanding of reasons for cycles in lobster abund-
ance, and possibly provide a mechanism for predicting future fishery yields.











BEHAVIOR OF THE SPINY LOBSTER, Panulirus argus,
TO BAITED FLORIDA AND PROTOTYPE TRAPS -

By
George C. Miller and David L. Sutherland


INTRODUCTION

An objective of the Resource Assessment of Invertebrate Program, NOAA,
NMFS, Miami Laboratory, is to assist commercial small-boat fishermen of
Florida, The development of a more efficient lobster trap is one way to
help these fishermen.

The Florida wood-slat spiny lobster trap with a top entrance is in-
efficient because it allows legal-size lobsters to escape. The design of
the trap incorporates few features relevant to lobster behavior, ecology,
or habitat. The top entrance of the Florida trap forces lobsters to ex-
pose themselves to predators, lengthens the time necessary for lobsters
to find the entrance, and allows possible escape by orientation toward
light coming in through the top of the trap.

A prototype trap was developed with a low, broad entrance near the
bottom of the trap, hinged wires across the entrance that swung into the
trap but could not swing outward, and a solid top. The wide entrance near
the bottom of the trap was accessible to animals seeking food or shelter.
Hinged wires were evenly spaced across the entrance to keep legal-size
lobsters in the trap while allowing illegal-size lobsters ("shorts") to
escape. The solid top was incorporated into the design so lobsters could
use the trap as a niche, similar to the overhanging reef ledges beneath
which they normally congregate and hide.

A study was conducted to determine: (1) the behavior of lobsters
to Florida and prototype traps; (2) the behavior of lobsters outside the
Florida trap when bait was in different locations in the trap; (3) methods
of entering; (4) methods of escaping; and (5) their behavior to movable,
hinged wires in the prototype entrance. This paper presents the results
of this study.

MATERIALS AND METHODS

The spiny lobsters were collected at the Elliot Key Marina, Biscayne
National Monument, January 23, 1976. Divers randomly captured 7 male and
3 female lobsters from the undercut marine seawall by hand or loop snares.
The animals ranged from 52.9 to 68.8-mm carapace length (average 61.1-mm)
and from 140 to 305 g (average 221.8 g) in weight. Two lobsters moulted
near the end of the study. All lobsters were released at Elliot Key after
completion of our study.

1 Contribution Number 479. Southeast Fisheries Center, Miami Laboratory,
National Marine Fisheries Service, NOAA, Miami, Fl., 33149.









Traps used were the standard Florida trap (Cope, 1959; Noetzel and
Wojnowski, 1975) and a prototype trap. The Florida trap measured 0.8 x
0.6 x 0.4 m (33 x 22 x 16 inches). It was constructed of cypress laths
nailed at 25 38-mm intervals on a rectangular frame of 25 x 51-mm cypress
strips. A funnel in the center of the roof was the trap entrance. The
funnel entrance measured 178 x 203-mm (7 x 8 inches) and was constructed
of standard width, 152-mm (6 inch) long laths, which extended down into the
trap. The trap was weighted at each end with concrete poured into bottom
partitions.

The prototype trap, except for the roof and entrance, was similar to
the Florida trap in size and construction. The roof was a solid sheet of
marine plywood, 10-mm (3/8 inch) thick. The trap entrance, 127 x 508-mm
(5 x 20 inches), was 127-mn (5 inches) above the trap floor and extended
across the width of one end of the trap. The entrance margin was 25-mm
(1 inch) thick pine boards which extended 203-mm (8 inches) into the trap.
Nine vertical hinged wires were spaced at 51-mm (2 inch) intervals across
the inside edge of the entrance. The light-gauge, steel wires, approx-
imately 2-mm (1/16 inch) in diameter, were hinged at the top of the entrance
to a 10-mm diameter steel rod. The free end of the wires fitted into slots
notched in the lower inside edge of the entrance. The entrance design per-
mitted lobsters to push the wires inward upon entry but not outward to
escape from the trap. This prototype is called the "Bar-room" trap.

Both traps were modified for the study by replacing the horizontal
wood laths along one side of the trap with a 6-mm (k inch) thick pane of
plate glass.

The traps were baited with a piece of cowhide and mackerel or mullet.
During the initial observations of the Florida trap, a rectangular, wire
mesh container baited with cowhide and mackerel was placed on the trap
floor, directly under the entrance. During subsequent observations, cow-
hide and mullet were placed in separate, perforated, plastic, pint con-
tainers and fastened to the trap ceiling next to the entrance. When
observations were made of the Bar-room trap, the wire mesh bait container
with cowhide and mullet was placed on the center of the trap floor. Fresh
fish bait was placed in the containers every second day; one piece of
cowhide was used during the entire study.

Lobster behavior to baited traps was observed with closed-circuit
underwater television cameras in a saltwater settling tank at the Miami
Laboratory. The settling tank measured 14.6 x 24.4 x 0.7 m (48 x 80 x
2.3 feet), and the lobsters were confined to a 5.5 x 7.0 m (18 x 23 feet)
area containing the traps and television cameras. One baited trap was
observed with two cameras each day.
2
A Hydro Products- Model TC-110 underwater television camera was placed
approximately 0.5 m (1.5 feet) from the right-front corner of the Florida
trap to view the entrance. The camera was placed at the left-front corner
to view the Bar-room trap entrance. To view the entire trap and the im-
mediate surrounding area, a Hydro Products model TC-125 camera was posit-
ioned approximately 2 m (6.5 feet) from the center of the glass side of
2 Reference to trade names does not imply endorsement of the product
by NOAA, NMFS.









the trap. Two 500-watt Hydro Products LQ-10 quartz iodide lights on each
side of the trap provided night time illumination.

The cameras and lights were operated, monitored, and video tape re-
corded from a nearby room in the Miami Laboratory. Pictures from each
camera were viewed on separate television monitors and were recorded on
Sanyo model VTR-1200 video recorders. Video tape recorders were run 6-24
hr/day during the study, or an average of 15.5 hr/day. The video tape re-
corders were run at a tape speed of 7 inches/sec when personnel were pres-
ent to view the closed-circuit picture. At night, or whenever personnel
were not present, the recorders were run at a speed of 1-1/16 inches/sec.
Every hour or 7 hr, respectively, the video tapes were rewound and review-
ed for lobster observations. Video tapes showing lobsters entering or
exiting the traps were saved for further analysis while other tapes were re-
used.

BEHAVIOR OF THE SPINY LOBSTER TO THE FLORIDA TRAP

Behavior Outside the Trap

The behavior of spiny lobsters to a Florida trap depended on the lo-
cation of the bait container in the trap. Lobsters continually tried to
enter at or near the trap's base when the bait was placed on the trap floor.
They generally circled the trap once and tried to enter by pushing against
the glass or by pushing head-first through the gaps between the bottom
three laths of the trap's walls. Further efforts to enter the trap were
concentrated near the bottom gaps in the wall opposite the glass. When
lobsters were unable to enter the trap through the bottom gaps head-first,
it was not unusual for them to try to enter sideways or tail-first. Lobsters
seldom crawled onto the roof and rarely entered the trap when the bait was
on the floor.

When bait containers were attached to the trap ceiling near the en-
trance, lobsters frequently climbed up the outside walls and tried to enter
the trap through gaps near the top of the trap. Lobsters were persistent
climbers, moving slowly up and down and back and forth on the walls. Dur-
ing these movements, they repeatedly tested the same gaps trying to gain
entrance. Most lobsters tried to enter the trap through gaps in the trap
wall, opposite the glass; little time was spent by the lobster searching
along the ends or the glass wall. Lobsters frequently climbed on top of
the trap then turned and climbed down the wall, probing for an entrance.

Lobsters reaching the top of the trap often walked directly from the
edge of the trap roof to a point directly above the bait container. When
the animals were given a choice of two bait containers, one containing
mullet and the other cowhide, they always moved directly to a point above
the mullet. The lobsters then assumed a head-down, tail-up position, with
the first pair of walking legs extended downward between the laths toward
the bait container. After about 2 minutes of "pawing" at the top of the
bait container, lobsters would find the entrance and enter the trap. Al-
though the animals were not individually marked, we estimated it took from
1 to 3 hours for a lobster to enter a Florida trap.










Lobsters generally entered the trap head-first. At the entrance, they
folded their antennae to their sides and crawled down the funnel, gripping
the laths with their dactyls. At or near the lower end of the funnel, the
lobsters released their grip and settled to the trap floor. When the bait
was attached to the roof, some lobsters crawled down and around the lower
end of the funnel and directly onto the container. One animal entered the
trap tail-first and backed down and around the funnel onto the container.

Behavior Inside the Trap

The lobsters inside the Florida trap were inactive, fed, or made ap-
parent efforts to escape. They successfully extracted bait from the bait
containers. After feeding, the animals became inactive. This, in turn,
was followed by more feeding or escape efforts.

Lobsters trying to escape from the trap behaved similarly to animals
trying to enter the trap. Persistent climbing, probing, and efforts to
squeeze between the laths were observed. One exceptionally active lobster,
during a 1-2/3 hr period of time, frequently pushed against the glass,
climbed every lath wall to the ceiling one or more times, and repeatedly
tried to squeeze through every gap between laths.

Lobsters escaped from the trap only when bait containers were suspend-
ed from the ceiling and lobsters were attempting to feed from them. The
bait container was reached by the animal in two ways: (1) by crawling
from the floor, up the wall to the ceiling, and then onto the container;
or (2) by curling the tail-fan (telson and uropods) under the abdomen and
rearing up on the posterior walking legs, grabbing the container with the
front walking legs, and pulling themselves up onto the container. The
animals, in moving around on the bait container, crawled into, up, and out
of the adjacent entrance funnel and escaped. In one instance, a lobster
leaving the trap through the funnel was pushed back into the trap by a
lobster entering the funnel. Some lobsters climbed out of the funnel onto
the top of the trap, tried to reach the bait container from the roof, then
re-entered the funnel and climbed back onto the bait container. Lobsters
only escaped when trying to feed at the bait containers.

BEHAVIOR OF SPINY LOBSTERS TO THE BAR-ROOM TRAP

Behavior Outside the Trap

The behavior of lobsters to the Bar-room trap differed from behavior
to the Florida trap because of the wide entrance near the trap's base.
Lobsters generally found the entrance to the trap during their first cir-
cuit around the trap while probing between laths. Upon locating the en-
trance, the animals climbed up onto the board ledge and used their antennae
to touch and probe the metal wires obstructing their passage. With an-
tennae folded back, the lobsters walked head-first through the entrance,
pushing from three to five wires inward in the process. Lobsters hesitated
briefly when partially through the wires, then continued into the trap
without any difficulty. The time from when the lobsters were first observed
outside the trap until they entered it was usually less than 4 minutes.











Behavior Inside the Trap

The behavior of lobsters in the Bar-room trap was similar to that
observed in the Florida trap. After feeding at the bait container on the
floor of the trap, lobsters pushed against the glass wall, climbed the
lath walls, and tried to squeeze between the laths to get out of the trap.
Some lobsters tried to escape by going under the board ledge at the en-
trance, rather then over it; others used the ledge to hide or rest under.
They frequently located the trap's large entrance, but started searching
for another place to escape after they were stopped by the wires guarding
the entrance. The wires were spaced across the entrance at intervals
designed to allow escapement of "shorts" and to retain large animals.
The lobsters, however, often placed their antennae on either side of in-
dividual wires, rather than between them, resulting in the lobsters butt-
ing and pushing against the wires. Eventually, all lobsters in our study
escaped between the wires.

SUMMARY

Florida Trap

Spiny lobsters spend considerable time and effort entering a baited trap.
Their search outside the trap is orientated towards the bait. Bait con-
tainers attached to the ceiling of the trap attract lobsters to the top of
the trap, whereas containers on the trap floor attract lobsters to the
trap's base. Lobsters generally enter a trap by crawling head-first down
the funnel entrance. Lobsters escape from a trap while attempting to feed
at the bait containers when the containers are mounted near the entrance.
Lobsters did not escape by swimming out through the funnel entrance.

Bar-room Trap

Lobsters locate and enter the large entrance near the trap.'s base in
minimal time. Wires at the trap entrance are not a hinderance to entry.
Appropriate spacing of the wires across the entrance allows illegal-size
lobsters to escape.

ACKNOWLEDGMENTS

We thank Gary Davis and Dan Robbins, U.S. National Park Service, for
assistance in obtaining the spiny lobsters used in our study. Alan Craig,
Florida Atlantic University, kindly imparted knowledge to us on the biology
and fishery for the spiny lobster at the start of this study.

LITERATURE CITED

Cope, C. E. 1959. Spiny lobster gear and fishing methods.
U.S.F.W.S., Fish. Leafl. 487, 17 p.

Noetzel, B. G., and M. J. Wojnowski. 1975. Costs and earnings in the
spiny lobster fishery, Florida Keys, Mar. Fish. Rev.,
37(4):25-31.
































Figure 1. Glass side view of Florida
spiny lobster trap.


Figure 2. Glass side view of prototype
"Bar-room" trap.


II I











ATTRACTANTS OF THE SPINY LOBSTER, Panulirus argus

by

Barry W. Achel

Research in our laboratory is directed towards understanding chemical
sensing in the Spiny Lobster. One project, supported by the Florida Sea
Grant Program, evaluates the possibility that simple organic compounds are
sufficiently attractive to lobsters that, when appropriately packaged for
release, they will serve as a convenient, economical, effective trap bait
for the fishery. First, it was established that low molecular weight com-
pounds are effective chemostimulants for this organism. Then 113 specific
compounds were assayed and ranked for their ability to physiologically
stimulate known low threshold chemoreceptor organs of the lobster. The 18
most stimulatory of these compounds were, in turn, assayed for their ability
to behaviorally attract lobsters to sources of these odorants.

Compounds varied in their behavioral attractiveness, but the most
attractive single compound was citric acid. L-ascorbic acid and succinic acid
ranked 2nd and 3rd, respectively, when tested over three ranges of concen-
tration. Nicotinic acid was the only compound appearing to elicit repul-
sion at the concentrations tested, although the assay was not designed to
test repulsion, per se These studies indicate that simple organic com-
pounds, by themselves, are functional attractants for the Spiny Lobster.

Concomitant laboratory experiments evaluated the effectiveness of
potential release vehicles. Membrane-limited diffusion chambers, agar and
gelatin gels, and plaster of paris blocks leached too quickly ( 24 hr)
for presently used trap fishing intervals. Retention of up to several
weeks was obtained from a patented laminate timed-release system developed
by Herculon, Inc., N.Y., N.Y. Subsequent initial field testing of the lam-
inate system using standard commercial fishing technique indicated that
citric acid at concentrations of 1 and 10 gm/trap/4 day set fished better
than empty traps, but less well than cowhide controls ("concentration" un-
known, but maintained at saturation levels in the bait container). Vari-
ability in catch/trap, however, statistically invalidated the observed
differences. Further field testing is planned.

Company estimates that dry chemicals like citric acid can be manu-
factured into laminate-release form for approx. $.10 per pound (454 gm)
suggest that the citric acid/laminate system would be economically compatible
with presently used baits. Final economic considerations, however, await
field trial determination of effective concentrations. Convenience and
ease of handling of the laminate would certainly be superior to natural baits.
Consideration has also been given to the availability of citric acid as a
by-product of Florida's citrus industry.

1 Department of Biological Sciences, Florida Atlantic University,
Boca Raton, Florida, 33431. B. Johnson and E. Clark participated
in this study.










BIOCHEMICAL SYSTEMATICS AND PROBLEMS OF LARVAL RECRUITMENT
IN THE SPINY LOBSTER, Panulirus argus

Robert A. Menzies, J. Michael Kerrigan and Paul Kanciruk1


The maintenance of an exploitable animal resource such as the lobster
fishery depends on a number of factors, not the least of which is the rate
at which young enter the fishery. Our studies have focused on identification
of adult populations giving rise to the larvae which support the Florida in-
dustry.

The problem is crystallized by models of two extreme possible situations.
Larvae entering the Florida nursery were believed to have originated princi-
pally from Florida (lower portion Figure 1). However, studies in the 1960's
principally sponsored by the now Florida Department of Natural Resources,
suggested a quite different pattern of larval transport and recruitment to
Florida (Sims and Ingle, 1966). This view is schematized in the upper portion
of Figure 1. Larvae spawned in Central and South America are "trapped" in
currents eventually feeding the Gulf Stream. In the terminal planktonic stage
they move (or are transported) shoreward and enter the closest nursery area.
Surface currents off the Southeast Florida coast are predominantly unidirect-
ional north-flowing (east in the lower keys) and it was assumed that Florida-
spawned larvae were transported out of the area. The existence of counter-
currents and gyres (long known to local fishermen and mariners) were not
believed to be sufficiently strong or prevalent to counteract the net removal
of Florida-spawned larvae. In the past few years however, more precise measure-
ments of rate and direction of current flow have been made. Data emerging
indicate that not only are there strong counter and shoreward currents but
some of these are persistent for large portions of the year. Notable among
these studies has been the work of Brooks and Niiler (1975) of the Nova Uni-
versity Oceanographic Center. In 1972, they measured current intensity and
direction as well as other physical parameters at numerous stations along a
line from Key West to Matanzas, Cuba. Their studies revealed a countercurrent
extending approximately 25 km from shore (Key West). The countercurrent was
contiguous from surface to bottom and persisted throughout the measurement
period (spring and summer). Thus, not only do strong countercurrents exist,
but they are present at the time of maximum spawning in the Florida Keys.
Conceivably, a large portion of Florida larvae could contribute to local
recruitment by developing within this countercurrent and associated eddies.
The knowledge of the relative size of this possible contribution compared to
foreign recruitment is necessary for fishery management.

Our approach to the problem involves concepts of population and biochemical
genetics. The former is best exemplified by the following illustrations.
The frequency of blond hair/blue eye individuals is higher in Sweden than in
most areas of Asia. These frequencies will remain the same generation after
generation, i.e., in an equilibrium state, as long as these populations remain
reproductively isolated. In the Spiny Lobster's case, the principal mode of


1. Life Sciences Center and Academy of Marine Sciences Laboratory,
Nova University, Fort Lauderdale, Florida, 33314.
22








gene flow between populations would be at the larval stage. Ignoring for the
present natural selection at sea, the gene frequencies of post-larvae enter-
ing a nursery should reflect: a) a single parental population if stocks are
locally sustained; or b) a composite of all parental populations contributing
to the pool of larvae mixing at sea.

Since genetically controlled morphological features such as blond hair
and blue eyes are of limited use in studying lobsters, we have resorted to
genetic markers that can be detected by biochemical techniques. Every enzyme
is a reflection of the gene(s) specific for that enzyme. Differences in en-
zyme structure which can be detected with biochemical techniques therefore
reflect differences in the information content of genes coding for that enzyme.

Many of these differences are revealed as different rates of movement
by enzyme molecules in an electrical field (electrophoresis). Within a class
of enzymes all catalyzing the same reaction several subgroups with different
charge per molecule may exist. The frequencies of animals in a population
possessing different subgroups reflect different frequencies of alleles* for
a particular gene. Figure 2 illustrates principles of our approach. The
figure shows two chromosomes and the position (locus) of a gene, "A". One
chromosome contains the "a allele at the A locus and the other chromosome
contains the "a" allele. This individual is thus heterozygous at the "A"
locus. In the cell, the process of protein synthesis "translates" the genetic
information into enzyme molecules. The biochemist can make a tissue extract
containing the enzymes and separate them in an electrical field. After per-
forming a staining reaction specific for all "A" locus enzymes in our hetero-
zygous lobster example, enzyme product bands would appear at the al and a2
positions in this gel. In the electrophoretogram (Figure 2), the patterns for
two homozygous individuals are also shown. Only the aI band is present in the
al/a individual. The heterozygous animal is denoted a /a2. By examining a
sample of individuals from a population and enumerating electrophoretic pheno-
types, the frequencies of alleles al and a2 can be estimated. Table 1 is a
summary from three hypothetical populations with different allele frequencies
for a1 and a Populations can be compared on the basis of allele frequencies,
p and q, or directly from phenotypic frequencies.

Figure 3 is a summary of our methods. Tissues are dissected and stored in
vials at -20C. For analysis, a small portion, 200-300 mg, is homogenized in
two ml. of medium H (0.25 M sucrose; 10 mM Mg Cl2; 50 mM KC1, 50 mM Tris-
HC1, pH 7.5). After centrifugation at 30,000 x g for 30 minutes in the cold,
a portion of the supernatant (5-5041) is removed for electrophoretic analysis
and the rest stored at -200C. Electrophoresis is performed on polyacrylamide
gels in the cold (approximately 40C). The gel concentration used in obtain-
ing data in this report was 8.5% acrylamide and 3% bisacrylamide. After electro-
phoresis, gels were sliced longitudinally and each half stained for esterase
activity with o<-napthylacetate as substrate (Shaw and Prasad, 1970). Figure
4 shows the distribution of bands in tail muscle with esterase activity. In
the Spiny Lobster over 16 bands of esterase activity can be detected. A pre-
liminary estimate of the number of esterase genes (loci) is 8. Some tissues


* Allele is the term used to denote subtle differences in the same gene set
(locus). Since lobsters are diploid, i.e. have two sets of chromosomes,
each individual can have either two of the same alleles homozygouss state)
or one each of two different alleles heterozygouss state).








such as hepatopancreas show many bands while others such as tail muscle con-
tain only a few in reproducibly detectable amounts. However, in the latter
case interpretation of phenotypic patterns is less complicated. In Figure
4 the predominantly staining area at the anodal end is designated the EF 4
locus. This region appears to contain a single polypeptide enzyme system
with four alleles designated as -3, 0, 5 and 10. The designations are based
on electrophoretic mobility relative to an index band in the standard. We
used this hypothesis to calculate the expected zygotic frequencies as pre-
dicted by the Hardy-Weinberg Law for several populations of adults. Expected
and observed frequencies are described for animals from Elliot Key Marina in
Biscayne National Monument (Table 2). Chi-Square tests yielded non-significant
differences indicating the data are consistent with the Hardy-Weinberg hy-
pothesis.

One of our goals is to determine which genes might be influenced by
physiological or environmental factors. A preliminary investigation as to
the influence of some parameters was made with the Elliot Key population.
Phenotypes were constructed based on bands 27, 24, 17, 10, 5, 0, -3. Eleven
phenotypic groups were obtained. Neither sex nor size affected the distribution.
of phenotypes among animals. Molt condition and/or season did not appear to
affect distributions of phenotypes when band 24 was deleted. However, band
24 did occur in higher frequencies in post-molt animals, most of which were
collected during the winter. Similar correlation analyses were performed on
the distribution of the EF 4 locus alone. No effect of size, sex, season or
molt condition was detected (Table 3).

Preliminary population comparisons (Chi-Square) for the EF 4 locus are
shown in Table 4. The five populations compared are Mores Island, Walker Cay
(both Bahamian Little Bahama Bank), Belize (C.A.), Boca Raton and Elliot Key,
Florida. Between population comparisons showed Elliot Key and Boca Raton to
have significantly different allele frequencies as compared to Belize and
Walker Cay. All other tests were non-significant.

It must be stressed that the data presented here are preliminary. Pop-
ulation comparisons, to be valid, must be done for several genes, i.e., other
enzyme systems. Our prime objectives now are to continue working out details
(genetics, physiological and environmental influence) of several more enzyme
systems primarily in adults and to verify the use of these systems in compar-
isons between post-larvae and adults. With the collaboration of Mr. Ed Little
(D.N.R.) and Mr. Gary Davis (U.S. National Park Service) we hope to obtain
post larvae from the Boca Chica (Key West) area and Elliot Key area. Ulti-
mately, it may be necessary to obtain phyllosome larvae from plankton tows to
complete the circle of population comparisons. When these studies are complete
it should be possible to delineate the geographic domain of all populations
studied.

We would like to acknowledge the collaboration of Mr. Gary Davis of the
National Park Service and everyone at Biscayne National Monument who aided
in animal collections at that site; Dr. Alan Craig for the Boca Raton animals;
Mr. Hartly Lowe of Walker Cay for animals from that location; The International
Trading Corp. for animals from Mores Island and Dr. Albert Jones of National
Marine Fisheries Service for the animals from Belize. This work was supported
in part by a grant from the Florida Sea Grant Program.










REFERENCES


Brooks, I. H., and P. P. Niiler, 1975. The Florida Current at Key West:
summer 1972. J. Mar. Res., 33(1):83-92.

Shaw, C. R., and R. Prasad, 1970. Starch gel electrophoresis of enzymes -
A compilation of recipes. Biochem. Genetics, 4:297-320.

Sims, H. W. Jr., and R. M. Ingle, 1966. Caribbean recruitment of Florida's
Spiny Lobster population. Quart. J. Fla. Acad. Sci., 29(3):207-242.


Flori (I


A. Open System


/ arvae from Keys


Bahamas

f' t I


Larvae from Brazil,
Venezuela


B. Closed System


Keys I
P, f 'or
r ,,


25


FIGURE 1


C=:


















0a2































ALLELE
02 a1

*a2 *a1

02:=p ~:=q
2n 2n


FREQUENCY
animals genomes

n 2n


a1


ORIGIN


FIGURE 2
















Pt
I'
I;
r^


FIGURE


>>bm**





















~EK> .: ~ .1


4;







.-2



















Al
gA-


FIGURE 4


yr -r~ .

r,
r
._tt:


c-


^- ': r C

-~ .. --~c:


-r rr
~~;i ?; ;7;.
'~R~Z"'
1


`%. ~s:

:~tli~
- r


~~.

C

i r
ir







~-:~ -




~,
F~L~IPi~~ ~Y ri~,
*r


~I -c- c-


. I-:C
'-:*LX -*:










TABLE 1
COMPARISON OF HYPOTHETICAL
POPULATIONS


Population


Allele Treq.


al/al
-2
P


.10
.25


.90


.25


Zygotic Freq.


al/a2
2pq
.18
.38
.50


TABLE
HARDY-WEINBERG FIT OF EF4 LOCUS

Observed and Expected Zygotic Expression
-3/-3 0/0 -3/0 -3/5 -3/10 5/5 10/10 0/5 0/10 5/10 X2


Walkers 0
Cay 49 .005


0 1 0 0
.02 .02 .44 .5


8 11 1
10.3 12.7 .9


0 0
.27 0


0 2 0
0 .6 0


0 13 14 5 2 12
0 10.3 9.6 3.3 3.2 19.6


0 11 10 3 7 19
0 9.7 10.6 4.4 4.6 20.2


0 38 22 4 9 49
0 33.5 20.9 4.4 7.0 53.0


0 0 0 3 1 12 6 3 1 20
.09 .09 .18 2.2 3.1 13.4 6.3 2.2 1.5 18.4


0 0
.06 0


5 7 2 0 8
4.6 5.5 1.0 1.1 10.1


3 15 4 0 24
6.3 15.9 1.5 2.3 20.0


7.445


2.254



1.004



2.696



2.814



9.324


all X2 values not sig. at the .05 level or better


.81
.56
.25


Sample
Area N


1 27
1.0 22.7


1.4
5


Boca
Raton 46


Marathon
Key 50


Elliott
Key 124


Boca 46
Chica
pueruli

Mores
Is. 22


Belize
46


~


_____ ______ --









TABLE 3


EF4 LOCUS TESTED FOR VARIANCE CORRELATED WITH
MORPHOMETRIC CHARACTERISTICS AND SEASON


2
Variable X N


Winter/Summer

Male/Female

Molt; Hard/Soft

Size; 60mm, 61-70mm,
-70mm


.664

3.464

1.194


4.858


124

124

122


123


all X values not sig. at the .05


level or better


TABLE 4. Population Comparisons At The EF4 Locus (Chi-Square Of


TABLE 4. Population Comparisons At The EF4 Locus (Chi-Square Of
Zygotic Expression)


B.R. E.K. M.I. W.C.


Boca Raton -

Elliot Key 4.89 -

Mores Island 1.14 4.40 -

Walkers Cay 9.62** 9.29* 2.14 -

Belize 12.96 ;17.380 4.33 3.08



sig. at .1 or better
** sig. at .05 or better
sig. at .025 or better










A DATA MANAGEMENT SYSTEM FOR THE FLORIDA SPINY LOBSTER FISHERY1


David C. Simmons, James R. Zuboy, and Edward A. Perez2


INTRODUCTION

The National Marine Fisheries Service (NMFS), Miami Laboratory, is
developing a data management system for the Florida spiny lobster fishery.
By working closely with industry and other agencies, we intend to utilize
data sources presently available and coordinate some primary data collec-
tionto construct a spiny lobster data base. This base will be accessible
by remote computer terminal and will provide information on the fleet, land-
ings, commercial catch and fishing effort, biology, economics, and recrea-
tional aspects of the fishery. An important aspect of the design of this
system is that it will be cost effective, and the information will be avail-
able on a real-time basis. This concept of handling spiny lobster fishery
data is applicable to other fisheries.

DATA BASE

The data base is comprised of eight files designated LAND1, LAND2,
FLEET, FLEET2, COMMER, SPORT, BIOLOG, AND ECONOMY (Figure 1).

LAND and LAND2

Each fish dealer is required to submit a monthly report to NMFS on the
pounds of fish and shellfish purchased from fishermen or produced by the
dealer. Data on pounds landed and average price of spiny lobster from these
reports are included in the data base in file LAND1. Monthly reports for
1975 and 1976 have been entered into the system. NMFS routinely contacts
several major dealers by phone to determine the quantities of lobster landed
on a daily basis. These data are also being entered into the data base in
file LAND2.

FLEET and FLEET2

Information on the commercial fishing fleet is supplied by the Florida
Department of Natural Resources and is composed of two files. FLEET1 consists
of information taken from spiny lobster license applications and includes
name and address of license holder, permit number, boat documentation or
Florida registration number, etc. FLEET2 consists of information taken from
lists of vessel documentation and Florida registration and describes each fish-
ing craft by vessel size, year built, hull material, etc. Both of these files
are in the system and accessible by computer terminal.


1. Contribution Number 475. Miami Laboratory, Southeast Fisheries Center,
National Marine Fisheries Service, NOAA, Miami, Fl., 33149

2. U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration
National Marine Fisheries Service, 75 Virginia Beach Drive, Miami, Fl.







COMMER

No data are presently collected on catch per unit of fishing effort for
the commercial spiny lobster fishery. To monitor the fishery, it will be
necessary to obtain these data logbooks are a good method of doing this.
For a logbook system to succeed, support and cooperation of the industry are
essential. A draft logbook has been developed, and we have solicited comments
and suggestions on the design from fishermen and biologists. Catch and effort-
data are to be entered daily and each book covers one month. Completed logs
will be mailed postpaid to the NMFS Miami Laboratory and the data entered in-
to file COMMER. The National Park Service intends to collect similar data
from lobster fishermen working within the boundaries of Biscayne National
Monument, and they also plan to use the logbook. The University of Florida
Marine Advisory Program will help publicize and distribute logbooks.

SPORT

The magnitude of the recreational fishery is unknown and before optimum
harvest can be determined, the total harvest, both commercial and recreation-
al, must be known. C. Bruce Austin (University of Miami, Rosenstiel School
of Marine and Atmospheric Science) has developed an efficient method for
studying recreational fisheries and his report is included in this Proceed-
ings. By taking Bruce Austin's methods into consideration, the data manage-
ment system calls for NMFS to contract out for a survey of the recreational
fishery. The results will compose file SPORT.

BIOLOG

The University of Florida Sea Grant Program, the National Park Service,
and the Florida Department of Natural Resources are carrying out active
programs of biological research on spiny lobsters. We do not intend to begin
new studies of biological research, but will rely on input from these agencies.
Their continued work in areas such as migration, growth, stock abundance,
mortality, and recruitment is essential to the understanding of the dynamics
of the resource and the eventual management for optimum harvest. We will in-
clude their.biological observations in file BIOLOG, which will form a base
from which future observations can be compared.

ECONOMY

Guidelines need to be developed for making economic surveys of fisheries
for management programs based on optimum harvest. In this way, standard
economic surveys can be made by different groups that will be comparative
from one time interval to another. The data management system calls for NMFS
to contract out for an economic survey of the industry. The results will com-
prise file ECONOM.

COMPUTER SYSTEM

Description

We are using the time-sharing services of First Data Corporation (FDC),


3. Reference to this particular computer system does not imply endorsement
by NOAA, NMFS








Waltham, Massachusetts, to implement the data management system. FDC features
multiple DECsystem 10 computers, over 4 billion characters of disk storage, and
nationwide access to time-sharing and batch services. FDC supports all 110,
300, and 1200 baud ASCII terminals, 134.5 baud EDCDIC terminals, and remote
batch terminals. For data base management FDC provides two systems, IMARS and
System 1022.

We are using System 1022 for the spiny lobster data base. System 1022 is
a sophisticated, general purpose data management system for any application
that involves generation, storage, maintenance, and retrieval of information.
System 1022 features include the following.

1) easy-to-use commands:
a) English-like commands for all operations;
b) standard default values for commands reduce the amount of
user entered information required.

2) efficient operation:
a) immediate access to records based on user-defined keys;
b) any number of fields may be used as keys;
c) time consuming searches of entire data bases are seldom
required.

3) convenient manipulation of large data bases:
a) a data base may contain up to 13 data sets, logically
related to form networks or hierarchical data structures;
b) each data set may contain up to 260,000 records;
c) records may be any size and may contain any number of fields;
d) fields may be integer, real, date, or text formats;
e) fields are compressed internally to as little room as
necessary to represent the data.

4) sophisticated report generator:
a) a few simple commands can easily generate reports as
described by the user;
b) an efficient sorting command is available;
c) options for automatic pagination, titling, and formatting
are provided;
d) routine arithmetic functions such as row or column totaling
are standard;
e) comprehensive output editing features are available.

5). FORTRAN/COBOL interface:
permits skilled users to write efficient, customized programs
to handle complex data management applications.

Costs

The three primary costs of time-sharing services are for computer resource
units (CRU), connect time, and storage. FDC provides toll-free phone lines
from/to anywhere within the continental United States. There is no initiation
of service fee and no minimum monthly charge.


























SCOMMER ) BIO
BASE



SPORT ECON







Figure 1. Conceptual design of the spiny lobster data base.








The use of First Data's system resources is measured in computer resource
units. CRU's are derived from an algorithm which considers such factors as:
central processing unit (CPU) usage, duration of a session, number of input/
output transfers, number of file accesses, and the size of the workspace
allocated. The prime time (generally corresponds to normal working hours)
rate is 1.1/CRU; the non-prime time (evenings and weekends) rate is 0.754/
CRU, for interactive services.

Connect time, the actual time the terminal is connected to the computer
via telephone line, is based on two rates. The prime time rate is $7.50/hour.
The non-prime time rate is $5.00/hour. This cost can be minimized by effi-
cient use of the system, i.e., when you are not actually working log off the
system.

The cost for on-line disk storage is computed on the average number of
characters in storage per day. The following table illustrates this cost
schedule:

Number of Characters Cost per 1000 characters/day

0 5 million 1.00
5 10 million 0.83C
10 25 million 0.67?
25 50 million 0.50
Over 50 million 0.40?

Tape storage is also available and is preferable for files that will be
used infrequently. The cost is $2.50/month per tape and each tape holds
360,000 characters.

CONCLUSION

We have described a data management system for monitoring the Florida
spiny lobster resource, which provides for data storage and retrieval via
computer terminal, timely data summaries, and other data management applica-
tions Implementation of this system will provide a cost effective manage-
ment tool with the potential for generating analyses, which will lead to the
eventual optimization of resource use. The Florida Department of Natural
Resources, National Park Service, and University of Florida Sea Grant Program
are cooperating agencies.








4. Since this paper was presented, NNFS Southeast Fisheries Center has
established a new division called Technical Information and Manage-
ment Services (TIMS). The primary function of TIMS is to develop a
data management system for fisheries in the southeastern region of
the United States. The spiny lobster data base described in this
paper will form part of this regional multi-fishery data base.











SIMPLE AND INEXPENSIVE WAYS TO MONITOR DIVING FOR SPINY LOBSTER
IN THE FLORIDA KEYS

C. Bruce Austin1


INTRODUCTION

I think we would all agree that we presently need, and will more urgently
need in the near future, at least some minimal knowledge about the amount of
sport diving for Spiny Lobster in order to adequately assess alternative
commercial as well as sport fishery policies. The primary obstacle is that
we simply haven't come up with a way to obtain this information in a reasonably
inexpensive fashion. There are at least two costly factors. The diving grounds
are spread over a chain of islands with numerous land departure and return sites.
This makes any type of traditional creel census or even the most superficial
site interviews costly and complicated in terms of the experimental design.
Equally important (and frequently ignored by "comprehensive" one-time studies)
is that the monitoring must be conducted, if not constantly, at least on some
regular basis to develop time trends which constitute the most important type
of information, namely, is the number of divers increasing or decreasing from
year to year (and during each season).

MONITORING THE FIRST PRESEASON OPENING FOR DIVERS

During the first two day preseason opening (July 20 21, 1975) for Spiny
Lobster, Rick Warner and myself with the assistance of NMFS Southeast Fisheries
Center staff made an attempt at monitoring sport diving for Spiny Lobster in
Monroe and Dade Counties*. This was done by interviewing at four popular Monroe
County departure sites (Garrison Bight, Key West; Bahia Honda State Park;
Knight Key Park, Marathon; and Indian Key Fill, Islamorada) and three Dade
County sites (Homestead Bayfront Park, Matheson Hammock Park, and Crandon Park).

Instead of the conventional creel census method of interviewing every "Kth
boater" encountered, the interviewers approached all trailerable boats that
were retrieved on a specific portion of the boat ramp. The portion varied from
the whole ramp (where traffic was light) to approximately sixty linear water-
front feet at the busiest sites. Upon their return, boaters interviewed were
asked about that day's offshore destinations and activities. When diving for
Spiny Lobster was reported, the number of active divers, hours spent diving,
and total lobster catch were recorded. As is the case with most recreational
fisheries, the catch per unit of effort (as measured by divers or boats) had a
large variance.


1. Assistant Professor, Dept., of Economics, School of Business and Division
of Biology and Living Resources, Rosenstiel School of Marine and Atmo-
spheric Sciences.
Supported by Uni. of Miami Sea Grant and NMFS, Southeast Fisheries Center
w








Table A. Spiny Lobster Catches By Sport Divers, Dade And Monroe Counties,
July 20 21, 1975

No. of % of all % of % of % of Boats
Divers Catch Boats Boats Boats from Other
per per Lobster from from Counties
boat Catch Diver Fishing Dade Co. Monroe Co. or States

DADE x 3.21 8.31 2.52 44 97 0 03
COUNTY S 1.33 9.63 2.72
x
n 244 244 244
MONROE x 3.07 6.13 1.96 60 22 50 28
COUNTY S .24 1.80 .49
x
n 32 32 32


The sample size in Monroe County was small because of the large number of
departure and return sites. This makes it impractical to cover a sufficient
number of sites to obtain a large number of interviews.

The sample size in Dade County was larger (244) because departures and
returns were concentrated at a small number of marinas. In Dade the sample size
was large enough to experiment with various alternatives for reducing the vari-
ances of the estimators. For example, dividing diving by offshore area, "Skill
factors" based on reported annual frequency of lobster diving, and SCUBA vs.
free diving. None of these distinctions significantly reduced the variances.
This problem is a familiar one in the analysis of recreational fishing. The
statistical advantages of disaggregations according to expected important fish-
ing characteristics are offset (or made impossible) except with extremely large
sample sizes because of the rapidly diminishing number of observations in each
category.

While the catch per diver was relatively low, the total amount of sport
diving for Spiny Lobster was substantial. Total diving was estimated by combining
the percent of boats diving for Spiny Lobster (Table A) with aerial counts of
total boats offshore on each day. From knowledge of departure and return times
obtained from the interviews, it was possible to estimate what percent of the
total daily boating traffic was offshore at the time of the aerial boat census.
This facilitated adjustment of the instantaneous boat count to reflect total
traffic for the entire day.

Multiplying the estimated catch per diver times the number of divers per
boat times the number of boats resulted in an estimation that in Dade County
1289 pleasure.craft with 4138 divers captured 10,712 legal size (approximately
one pound) lobsters. Because of data limitations such calculations are not
presented for Monroe County.










LESS AMBITIOUS PLANS


While monitoring the first preseason opening was a valuable exercise,
this conventional approach is not a feasible way to monitor diving for Spiny
Lobster because it is too expensive to conduct on a continuous basis (over
one season, much less from year to year as would be required to obtain im-
portant seasonal and intra-seasonal trends).

We might ask ourselves what information we really need for present or
anticipated decision on Spiny Lobster. I believe that catch data may not
be that important. As with most recreational fisheries, catch data are of
questionable statistical reliability because of the large variances in the
estimators. Furthermore, as Gary Davis and others have pointed out, the
ultimate influence of divers on Spiny Lobster stocks may be more related to
diver contact with the animals than direct fishing mortality from capturing
them. There is little doubt that divers come into direct contact and
handle many more lobsters than they catch. How divers injure lobsters while
trying to catch them or alter their natural aggregations is not known. How-
ever, whatever the influences, they would not be reflected by catch data.
In this regard total diving "pressure" on the resource would appear to be a
better index than a poorly estimated indication of catch.

A SIMPLE WAY TO MONITOR DIVING

If we were satisfied with only monitoring total diving activity (from
boats), there may be a relatively simple and certainly inexpensive method to
obtain this information on a continuous basis (seasonally and intra-season-
ally). The method draws on a basic theory that recreators have established
recreational patterns with regard to time (time of day, day of week, season
of year). During the 1975 pre-season opening we observed that divers have
identifiable daily time patterns. Using some rather crude estimating methods,
this is how we attempted to adjust instantaneous aerial boat counts to re-
flect total daily traffic.

In September 1975 we began a comprehensive one-year study of recreat-
ional boating in Dade County.* This study was a first formal attempt to use
time-of-day (preference) curves to estimate total daily boating traffic from
instantaneous aerial boat counts. What was informally observed in the first
Spiny Lobster preseason opening and a year later documented in the boating
study was that boating traffic in the categories of linefishing, diving, sur-
face contact (e.g. skiing), and cruising have unique and relatively stable
daily time patterns.

Cumulative departures (D) and returns (R) follow logistic patterns
(Figure 2). The percent of boats that are offshore at any time of day is D-R.
If there were 100 boats observed offshore at 1200 hours then it can be esti-
mated that 100/D1200 ^1200 is the number of boats that will go offshore over
the entire day. If there is more than one offshore activity (e.g. fishing
and diving) then D-R used in the calculation of total daily traffic must be
calculated from D-R for each offshore activity weighted by relative amounts of

* Supported by Metropolitan Dade County Department of Parks and
Recreation and University of Miami Sea Grant.
38









each activity. (See the technical appendix analog computer circuit used to
calculate D-R for four activities).

The time of day curves (Table B and Figures 1 and 2) for each activity
and the prevailing mix of offshore activities were obtained from site inter-
views. The site interviews were the time consuming and costly component of
the study. Aerial boat census was a minor component. This leads to an idea
about monitoring the amount of diving by regular aerial boat census without
site interviews.

At the offshore areas where diving for Spiny Lobster is most prevalent
there are probably only two primary offshore activities! linefishing and
diving (including spearfishing). If the time curves for these two activities
were known and if they were statistically distinct and stable (low variances),
then the activity mix (proportions of boats engaged in linefishing and
diving) and total activity in both categories could theoretically be esti-
mated solely from aerial boat counts. Some simple arithmetic calculations
demonstrate how this could be done.

Imagine if an aerial boat count was taken at a specific time, for
example 1200 hours. We know from the time curves:

(1) Od(t) Nd+0f(t) Nf = n(t) where : Od(t) = percent of diving boats off-
shore (D-R) at time (t).

Of(t) = percent of fishing boats off-
shore (D-R) at time (t).
Nd = total boats engaged in diving
on that day.
Nf = total boats engaged in fish-
ing on that day.
n(t) = number of boats observed off-
shore (aerial census) at time (t)
At a particular time (t) we know:

Od(t) from time curves
Of(t) from time curves
n(t) from aerial count of boats offshore

We cannot solve equation (1) for the number of boats engaged in diving (Nd)
or fishing (Nf) because there are two unknown 'and only one equation. We must
know one of the values (e.g. Nf) to solve for the other (Nd). However, if
there were two aerial counts on the same day at different times we can solve
for the number of boats diving and fishing.

(2) first observation (t=l): Od(l)Nd + 0f(l)Nf = n(l)
(3) second observation (t=2): Od(2)Nd + Of(2)Nf = n(2)

Solving equation (2) for Nf

(4) Nf = n(l) Od(l)Nd
Of(l)














TABLE B. Departure And Return Times By Activity Averaged Over Five Dade County Marinas, 1975-76.


= percent of
= percent of

= cumulative

= cumulative


activity departing in time interval
activity returning in time interval

percent of activity that has departed

percent of activity that has returned


Time of _Percent Departures and Returns by Activity
Day C-uise Water surface contact i Dive/Spearfish Linefish Other
SR D R D R D R D R D R D D R D R

Pre 0600 .8 0 .8 0 .3 0 .3 0 .6 0 .6 0 1.8 .1 1.8 .1 7.0 .4 7.0 .4
0600-0800 2.5 0 3.3 0 .6 0 .9 0 13.1 0 13.7 0 25.5 .1 27.3 .2 3.1 2.0 10.1 2.4
0800-1000 13.5 0 16.8 0 18.3 0 19.2 0 42.6 0 56.3 0 35.9 .1 63.2 .3 18.1 2.5 28.2 4.9
1000-1200 35.4 3.4 52.2 3.4 37.5 1.2 56.7 1.2 29.8 1.9 86.1 1.9 20.4 5.6 83.6 5.9 14.2 6.5 42.4 11.4
1200-1400 29.1 12.4 81.3 15.8 31.9 9.9 88.6 11.1 9.7 13.1 95.8 15.0 8.3 20.1 91.9 26.0 10.3 8.9 52.7 20.3
1400-1600 14.0 29.1 95.3 44.9 9.0 25.1 97.6 36.2 2.8 32.9 98.6 47.9 2.9 34.6 94.8 60.6 18.3 24.8 71.0 45.1
1600-1800 3.1 41.5 98.4 86.4 1.5 46.7 99.1 82.9 .3 39.6 98.9 87.5 1.3 28.8 96.1 89.4 4.4 22.8 75.4 67.9
Post 1800 1.6 13.6 100.0 100.0 .9 17.1 100.0 100.0 1.1 12.5 100.0 100.0 3.8 10.6 99.9 100.0 24.6 32.1 100.0 100.0


D

R
D

R








S100

80
A.


6 8 10 12 2 4 6
noon tice


10 12 2 4 6
noon time


6 8 10 12 2 4 6
noon time


noon time


6
tice


6 8 10 12 2 4
noon


100

Sso
P4


6 8 10 12 2
noon


4 6
time


6 8 10 12
noon


2 4 6
time


Figure 1. Percent departures (D) and
returns (A) in the summer (July-
September, 1976) by activity


Figure 2. Cumulative percent departures
(D) and returns (R) in the summer (July-
September, 1976) by activity


30

20

10.








50
s o
$4 40
V

30

20

10









Substituting (4) into (3) and solving for Nd:


n(2) Of(2)n(l)

(5) Nd = Od(2) Of(1)0d(2)
1 Of(2)0d(l)
0f(l)0d(2)

For expository purposes we can assign values to the parameters in equation
(5) from Table B. Let us assume the aerial counts were made at 1100 and
1500 hours (mid-points in the time intervals). Further, assume 155 boats
were observed at 1100 hours and 100 boats at 1500 hours.

Table C. Hypothetical observations at 1100 and 1500 hours

Time D-R for diving D-R for fishing Number of boats observed

1100 Od(l) = .555 Vf(l) = .777 155
1500 Od(2) = .507 0f(2) = .342 100

Substituting the values in Table C into equation (5) indicates that a total
of 119 boats were engaged in diving on that day.

DISCUSSION

This method is very sensitive to the reliability of the time curves.
In addition, of course, it is necessary to know the time curves. The curves
that have been developed for Dade County might be satisfactorily applied to
Monroe County. The results of the recreational boating study in Dade suggest
that a modest amount of site interviewing in Monroe could test the applicabil-
ity of Dade's curves or construct new ones that would be more applicable for
Monroe. Fortunately, there is good reason to believe the curves are stable
from year to year. However, this is an hypothesis that can be easily tested
with a modest amount of interviewing each year.

Once the curves are known, aerial counts at two times on each sample
day in each designated offshore area could ascertain (without site interviews):

(1) number of boats at time of aerial count engaged in diving;
(2) total number of boats engaged in diving on that day;
(3) number of boats at time of aerial count engaged in fishing;
(4) total number of boats engaged in fishing on that day.

This may not appear to be sufficient information, but it is probably
the best we can hope for unless a very large amount of research money is spent
that, I believe, may not be justifiable given the additional information that
would be obtained from a more conventional type of creel census. This method
could answer the most important immediate and future question about sport
diving for spiny lobster, namely, is the number of divers increasing or de-
creasing (over each season and intra-seasonally).










Of course this method does not distinguish between all divers and those
diving for Spiny Lobster. However, I believe this can be done with a reason-
able degree of accuracy from the monthly trends in the numbers of divers.
Aerial counts would be required outside of the lobster season (August March)
for comparative purposes. We would expect a significant increase in summer
diving activity at the beginning of the lobster season (August) followed by
a gradual reduction through perhaps November. We don't know what to anticipate
during the winter tourist season beginning in December. However, with one
year's diving trends guiding the collection of additional information, I be-
lieve we could readily interpret future diving trends in terms of diving for
Spiny Lobster. Then regular aerial boat counts (approximately seven per
month) could provide the basic data on diving for Spiny Lobster in Monroe and
Dade Counties.











REPRODUCTIVE POTENTIAL AS A FUNCTION OF


FEMALE SIZE IN Panulirus argus

By

Paul Kanciruk1 and William F. Herrnkind


Specimens of the Caribbean Spiny Lobster, Panulirus argus, were diver
collected during the autumns of 1971-74 at and near the twin islands of
Bimini, Bahamas, as part of a larger study into the migratory behavior of
this species. This investigation into the reproductive potential of the
population was made with special reference to the Florida legal size (76 mm
or 3-inch carapace length).

Autumnal reproductive activity was high (40-60% gravid females) in
localized deep water populations at Bimini (Kanciruk and Herrnkind, 1976),
in contrast to that reported in much of the literature. We believe that
these data point out: 1) the superiority of diver sampling over trap sam-
pling (Morgan, 1974); 2) caution when averaging data from differing hab-
itats (breeding females were quite localized along the deep fringing reef
areas and were wholly absent from the shallow bank area); and 3) caution
when generalizing data obtained from one population/habitat to another.
Reliable diver survey at the Dry Tortugas (Gary Davis, pers. comm.) indi-
cates a lack of autumnal reproductive activity.

In all, 1438 females were diver-collected from varying habitats
(shallow bank sponge-sea whip areas and the deep coral habitats) and examined.
Size and presence of eggs were noted. In order to rank each size class in
terms of contribution to the estimated population egg production, an Index
of Class Reproductive Potential was developed:

Index = A x B x C/D
Where : A = # females in class/total sample
B = propensity of class to carry eggs
C = egg carrying capacity of average class female
D = constant (31.27)

The constant, D, was chosen to set the 76-80 mm (carapace length)
class's index to 100 as the standard. For example, the 76-80 mm class, which
made up 21.2% of the sample, had a 5.9% propensity to carry eggs, and, when
gravid, ag female of this size-range will carry approximately 2.5 x 105 eggs
(Mota-Alves and Bezarra, 1968). The calculated index is:

Index = .212 x .059 x (2.5 x 105) / 31.27

Index = 100.0

1 Present Address: Environmental Sciences Division, Oak Ridge National
Laboratory, Oak Ridge, Tennessee 37830.









Frequency of egg bearing, egg carrying capacity, Index of Class
Reproductive Potential, % contribution to total egg production, and a
relative measure of class productivity for each size class are given in
the table and figure.

The size frequency for the sample (Figure-l) indicates the population
is lightly fished. Larger lobsters are quite abundant in contrast to size-
frequencies of heavily fished populations where the frequency drops off
sharply at or near the legal size. The solid inverted triangles indicate
the 76 mm carapace length Florida legal size. Approximately 25% of the
sample consisted of females 76 mm or smaller, yet only 1.9% were observed
to carry eggs. In contrast, in the 96 100 mm females (comprising only 3.6%
of the sample) 19.2% were observed to be gravid. It Pas been estimated
that a 71 75 mm female when gravid carries 2.3 x 10 eggs and a 96 100
mm female carries 5.3 x 105 eggs.

When these factors are integrated by the Index of Reproductive Potential
an interesting pattern emerges (Table A; Figure 3). The size class most
productive is the 81 85 mm class, producing 26.3% of the estimated total
egg production (index = 233), although comprising only 9.6% of the total pop-
ulation. Very large females (>101 mm) are relatively less productive. The
size class that would be legally protected in Florida waters (< 76 mm)
appears to contribute insignificantly to total egg production, producing
only 3.2% of the eggs although comprising 25% of the population. As a class,
the 71 75 mm females exhibited a productivity of .15 as compared to 3.9
for the 76 100 mm class (a 26 fold increase).

In summary, the data for Bimini suggest that in the autumn small fe-
males (<80 mm) are quite unproductive in their contribution to total egg
production. Larger females contribute the most. In addition, a female
captured just at or slightly larger than legal size (76 78 mm) probably
has not had the chance to mate and produce eggs.

These data are not unique to Bimini or to the Autumn. Recently, a
large sample (1574 females) from an unfished population at the Dry Tortugas
in the Spring (Davis, 1975), yielded similar results. The smallest berried
female captured measured 78 mm and the percent berried by size class peaked
at 96 125 mm.

The importance of this information to the Florida fishery is unknown.
There are many factors other than egg production that can influence populat-
ion size. However, if further investigation indicates that egg production
is critical in maximizing population size, then these data are of import-
ance. We then must insure the reproductive potential of the population act-
ing as larval source for our fishery (whether it be local or foreign). If
these data can be extrapolated to the unknown source populationss, they
indicate that a 76 mm carapace length legal size may be an inadequate protect-
or of reproductive potential in P. argus. An additional consideration is
protection of potential autumnal and other late-breeding stocks. For example,
selective habitats where late reproduction occurs might be closed to fishing.













10------


- h ~ ~ A.


250-

200-


yr


1




LW--


:70 71-75 76-80 81-85 86-90 91-95 96-100 1101

Carapace Length in mm


Figure 1. Size-Frequency of all Females.
Arrow indicates minimum legal size.


Figure 2.


Figure 3.


Percent of all Gravid Females vs. Size Class.
Note larger females were more frequently observed
to carry eggs.
Index of Reproductive Potential vs. Carapace Length.
The bulk of egg production is generated by large
females in the population even though they make up
a small proportion of total females.


r


C












TABLE A


INDEX OF REPRODUCTIVE POTENTIAL

Size Class of Female (Carapace Length) n 1438


70mm 71-75mm 76-80mm 81-85mm 86-90mm 91-95mm 96-100mm 101mm


A % of total


10.4 14.9


21.2 23.8


15.7


7.4 3.6


B % with eggs 0.0

C estimated # eggs
carried when
gravid (xl0 ) 2.0

D index of repro-
ductive potential 0.0

E % of total egg
production 0.0%

F productivity (E/A) 0.0


1.9 5.9 9.6 9.7



2.3 2.5 3.2 4.0


20.5


14.0



4.7


19.2



5.6


100.0 233.8 194.8 155.7 123.8


2.3% 11.2% 26.3% 21.9% 17.5% 13.9%


.15 .52 1.1


1.4 2.4 3.9


After Kanciruk and Herrnkind, 1976


LITERATURE CITED


Davis, Gary E., 1975. Minimum size of mature spiny lobsters, Panulirus
argus at Dry Tortugas, Florida. Trans. Am. Fish. Soc. 104(47:
675-676.

Kanciruk, Paul and William F. Herrnkind, 1976. Autumnal reproduction in
Panulirus argus at Bimini, Bahamas. Bull. Mar. Sci., 26(4) :
417-432.

Mota Alves, Maria I. and Roberto C. F. Bezerra, 1968. S6bre o Numero de
Ovos da Lagosta Panulirus argus (Latr.). Arq. Est. Biol. Mar.
Univ. Fed. CearA, 8(1):33-35.

Morgan, G. R., 1974. Aspects of the population dynamics of the western
rock lobster, Panulirus cygnus George. I. Estimation of population
density. Aust. J. Mar. Freshw. Res., 25:235-248


9.5



7.0


61.7


6.9%


_ _X_ ~__


~_~_ ~


--









FLORIDA'S PROGRAMS OF DATA RETRIEVAL
AND ANALYSIS FOR THE SPINY LOBSTER FISHERY

Charles R. Futch1


In addition to Spiny Lobster recruitment studies being conducted through
the Marine Research Laboratory, the Florida Department of Natural Resources
Bureauof Marine Science and Technology is working toward development of a
data retrieval system to more accurately assess dynamics of the fishery. A
computer-based system for issuing lobster trapping licenses has been design-
ed; implementation awaits funding. Such a system will allow interface of
other data files, including Florida boat registrations and commercial land-
ings statistics. The Bureau is also engaged in a cooperative program with
the National Marine Fisheries Service, Southeast Fisheries Center, Miami
Laboratory, to describe the capabilities of Florida's lobster fleet and to
derive catch per unit effort statistics for a sub-sample of the fishery.



1. Bureau of Marine Science and Technology, Florida Dept. of Natural
Resources, Tallahassee, Florida.











POPULATION STRUCTURE OF JUVENILE SPINY LOBSTER, Panulirus argus,
IN THE GRAND BAHAMA AREA

Gregg T. Waugh, B.Sc.1


A complete understanding of theCpiny lobster, Panulirus argus (Latreille)
resource, requires information covering its complete life cycle. Considerable
effort has been directed towards larval, post-larval and adult isages, but the
juvenile stage has been practically ignored. Lewis (1951) described the phyl-
losoma larvae of P. argus and was first to mention that foreign recruitment
may take place; that is, the local population may depend upon an external
supply of larvae. Lobsters in the Bahamas may come from eggs of lobsters in
the southeast Caribbean. Lewis, et al. (1952) described the first 11 post-
larval stages of P. argus from animals reared in the laboratory. Witham, et
al. (1968) wrote on the ecology and physiology of pueruli and post-larvae of
P. argus.

Adult spiny lobsters have been studied by many workers, e.g., Sweat (1968)-
growth and tagging, P. argus, Florida; Buesa (1969)- biology and fishery, P.
argus, Cuba; Morgan (1974a, b)- population dynamics, P. cynus, Australia.
Juvenile studies are less numerous, e.g., Chittleborough (1970)- recruitment,
P. longipes, Australia; Eldred, et al. (1972)- growth rate, P. argus, Florida;
Chittleborough (1974)- home range, homing and dominance, P. longipes,
Australia.

Various means of collecting post-larvae and small juveniles have been
documented: Witham (1968)- post-larvae, P. argus, Florida; and Phillips (1972)-
pueruli, P. longipes cygnus, Australia.

In Florida,work on adult spiny lobsters is being conducted by Warner,
Combs, and Gregory (University of Florida) and Davis (National Park Service).
Little (Florida Department of Natural Resources) intends to study early post-
larval stages. No one has proposed to study juveniles as intensively as is
needed, although Davis is doing some work on juvenile growth rates.

Not only are most researchers not collecting data on juveniles, but their
collecting techniques actually select against obtaining such data (Chittle-
borough, 1974). This occurs due to the dominance exerted by adults collected
in standard traps which prevents juveniles from entering the traps.

The objectives of my study are to:

1) determine number of juvenile lobsters in the study area.
This information is required to determine numbers of potential
recruits to the fishery and to help estimate the maximum
sustainable yield (MSY);

2) determine their survival rate, and attempt to identify the
juvenile lobster's major predators. This will aid in


1. Post Office Box F-3, Freeport, Grand Bahama, Bahamas
49












predicting future catches and also is a factor in
determining optimum harvest size for the individual, i.e.,
minimum carapace length. Lobsters should be harvested
before there is a large loss due to natural mortality. If
they must die, it would be better if they were used by man
and not lost to nature;



3) determine growth rate of juvenile lobsters.
This will be used to determine optimum individual
harvest size and possibly predict (with survival data)
future yields;

'4) determine rate of recruitment of juveniles into the
fishable stock. By knowing the number of lobsters present
at the beginning of the juvenile stage and those remaining
at the harvestable size I will be able to calculate losses
during the juvenile stage. Knowing the numbers present
when lobsters enter the fishery, I should be able to predict
potential catches of legal-sized lobsters.

The study area is located on the north side of Grand Bahama Island in
the Bahamas, near Man-o-War Bush Point (Figure 1). This area was chosen be-
cause of the known abundance of juvenile lobsters and my familiarity with
this part of the Island. Figure 1 is a map of the West End area showing the
study site.

Any ecological study must encompass at least one year, thereby showing
seasonal variations. For results of this study to be conclusive, data should
be collected over a three-year period to give annual variations. I will be
able to carry out this research for only one year for my Master's thesis.
This research will yield seasonal results and will be a valuable addition to
our knowledge of juvenile lobster biology in the Bahamas. The project should
be continued in the future to support or modify conclusions resulting from
this study.

As fishing effort increases, the need for proper management of spiny
lobsters becomes more apparent to ensure the future of the fishing industry.
This research could aid future management decisions by providing information,
conclusions, and recommendations concerning the population structure of
juvenile spiny lobsters.









LITERATURE CITED

Buesa, R. J., 1969. Biology and fishing of spiny lobster, Panulirus argus
(Latreille). Soviet-Cuban Fishing Research. Transl. from Russian
by Israel Program for Sci. Transl. Jerusalem. pp. 62-77


Chittleborough, R.G., 1970. Studies on recruitment in the Western
Australian rock lobster, Panulirus cygnus (George): Density
and natural mortality of juveniles. Aust. J. Mar. Freshwat.
Res., 21:131-148.

Chittleborough, R.G., 1974. Home range, homing and dominance in
juvenile western rock lobsters. Aust. J. Mar. Freshwat. Res.,
24:227-234.

Eldred, B., C. R. Futch and R. M. Ingle, 1972. Studies of juvenile
spiny lobsters, Panulirus argus, in Biscayne Bay, Florida.
Mar. Res. Lab., St. Petersburg, Fla. Spec. Sci. Rep. No. 35, pp.15.

Lewis, J. B., 1951. The phyllosoma larvae of the spiny lobster, Panulirus
argus. Bull. Mar. Sci., 1(2):89-103.

Lewis, J.B., H. B. Moore and W. Babis, 1952. The post-larval stages of
the spiny lobster, Panulirus argus. Bull. Mar. Sci., 2:324-337.

Morgan, G. R., 1974a. Aspects of the population dynamics of the western
rock lobster, Panulirus cygnus (George). I. Estimation of
population density. Aust. J. Mar. Freshwat. Res., 25:234-248.

Morgan, G. R., 1974b. Aspects of the population dynamics of the western
rock lobster, Panulirus cygnus (George). II. Seasonal changes in
the catchability coefficient. Aust. J. Mar. Freshwat. Res., 25:249-259.

Phillips, B. F., 1972. A semi-quantitative collector for the puerulus
larvae of the western rock lobster, Panulirus longipes cygnus (George)
(Decapoda, Palinuridae). Crustaceana, 22(2):147-154.

Sweat, D. E., 1968. Growth and tagging studies on Panulirus argus
(Latreille) in the Florida Keys. Fla. Bd. Conserv. Tech. Ser. No.
57, pp. 30.

Witham, R., R. M. Ingle and E. A. Joyce, Jr., 1968. Physiological and
ecological studies of Panulirus argus from the St. Lucie Estuary.
Fla. Bd. Conserv. Tech. Ser. No. 53, pp. 31.










AN ECONOMICAL METHOD OF TRAP FISHING FOR SPINY LOBSTER,
Panulirus argus, IN THE BAHAMAS

Gregg T. Waugh and Harold R. H. Waugh

Fishing for Spiny lobster, Panulirus argus, in the Bahamas with wooden
traps was first legalized for the 1973/1974 season. Spiny lobsters are
commonly referred to as "crawfish" by most Bahamians.

Prior to the 1973/1974 season the only legal method of harvesting spiny
lobster commercially was bully netting; traps or pots were outlawed. With
the advent of spearfishing and the increased value of catches, numerous spiny
lobsters are now captured by divers using a spear.

Converting our village fishermen from the spearfishing and bully netting
styles of commercial fishing to the use of wooden traps need not involve the
previously anticipated vast capital outlay.

For the past two seasons (1975/1976; 1976/1977) we were granted a
trapping license K-l by the Ministry of Agriculture and Fisheries, which
authorized us to fish in the Grand Bahama area (Figure 1). A 16-foot Boston
Whaler was outfitted with a trap puller obtained from the Fisheries Store.
A homemade tripod with an open block was installed, traps, ropes and floats
were purchased, bait obtained, and we were ready to begin trapping.

Our traps were set in 80-100 feet of water, thus making them invisible
to the naked eye, and too deep for us to be affected by spear-fishermen or
divers. Each trot-line had a buoy line 100 feet in length, rigged with a
pop-up or time-delayed release device (Richard, 1971). This device is made
of an alloy of magnesium and zinc, which corrodes or dissolves in salt water
at a known rate. A wire is attached through a braid of the rope approximately
40 feet below the float, with a second wire some 20 feet above the trap. After
connecting the two wires with the pop-up, the first trap overboard pulls the
float down below the surface of the water (Figure 2).

The capital investment necessary to or--ganize a one-boat, 300-trap fishing
unit is outlined in Table A. Two village fishermen could be established as a
fishing unit with a $12,000 investment.

The cost analysis covers 3 years, which equals the life time of the weak-
est gear component, i.e., the traps (Table B). The traps and engines were
depreciated over three years, whereas the rest of the gear was depreciated
over five years.

A summary of actual catch and effort data appears in Table C. Our
average catch rate of 0.3789 pounds (lb.) per trap day (td) is the figure
used in estimating the potential returns from this fishery. Trap day is de-
fined as one trap fishing a 24-hour period.


1. Post Office Box F-3, Freeport, Grand Bahama, Bahamas








Fishing 300 traps with an average soak time or fishing time of 30 days
per month results in 9000 trap days per month. Using our average catch rate
of 0.3789 Ib./td, the potential monthly catch equals 3,410.1 lb. This
weight, sold at the average-p;Gca&e-r pound whole weight of $1.50, would
gross the fishermen $5,115.15 per month. Based on an eight-month season,
the theoretical gross per year equals $40,921.20, quite a high return for
an investment of only $12,000. The potential earnings of our fishing unit
over a three-year period appears in Table D.

It is our contention that with the adoption of the outlined fishing
method, a fleet of small fishing boats could be outfitted at a much reduced
cost, which would also provide a significant boost to the local economy.
A loan program could be developed by the Ministry whereby interested fisher-
men would be set up to trap spiny lobsters for $12,000 per fishing unit.
Projecting our catch rates the loan could be repaid within the first year.
Thus a large expenditure is not necessary to establish a spiny lobster
industry, and those funds which could be allocated would assist a greater
number of fishermen by using our small but efficient fishing units.

In conclusion, by adopting our recommendations and fishing methods a
fleet of small Bahamian fishing boats could start to harvest the vast quantity
of spiny lobsters available in our nation's waters.




Figure 1. Grand Bahama (*) Study Area







Figure 2. Method Of Attaching Pop-ups To Buoy Line. Total
Length Of Buoy Line Is 100 Feet. Depth Of Water
Fished Is A Factor Of Length Of Buoy Line And
Positioning Of Pop-up.


6boys











T TRAPs To
< WtAtLlNr


buoys


Iw.


TO o7TER
TRos


TABLE A. Capital Investment Necessary In Organizing A One B-oat (16 ft),
300 Trap Spiny Lobster Fishing Unit.


Item Cost ($)


Boat (New Boston Whaler) $ 3,000.oo

Trap Puller (New 7 H.P. Gas Puller) 400.oo

Mounting 400.oo

Traps ($16 ea. rigged) 4,800.oo

Bait Cano (350 @ 34 ea,) 125.oo

Engine (New 85 H.P. Outboard) 2,200.oo

Other Expenses & Working Capital 1,075.oo

TOTAL $12,000.oo


WATC


~ ~~








TABLE B. Cost Analysis For A Small
300 Traps.


Bahamian Spiny Lobster Boat Fishing


Item Dollar Cost For Years 1 To 3
ItYear __Year_ 2 Year 3_
..Year I Year 2 Year 3


Variable Costs


Fuel
Oil and Oil Change
Bait
Brush
Gloves
Rain Gear
Vests
Wages
Repairs & Maintenance
Total Variable Costs

Fixed Costs
Depreciation
Traps
Boat
Trap Puller
Engine
Boat Cans
Loan
8% Interest on Loan

Total Fixed Costs


Total All Costs


$ 720.00

160.oo
960.oo
17.oo
60.oo
70.oo
20.oo
8,000.0o
1,000.oo
11,007.oo


1,600.oo
600.oo
133.34
733.34
41.67
12,000.oo
960.oo

16,068.35

27,075.35


720.00
160.oo
960.oo
17.oo
60.oo
70.oo
20.oo
8,000.oo
2,000.oo
12,007.oo


1,600.oo
600.oo
133.33
733.33
41.67




3,108.35

15,115.35


720.00
160.oo
960.oo
17.oo
60.oo
70.oo
20.oo
8,000.00
3,000.oo
13,007.oo


1,600.oo
600.oo
133.33
733.33
41.66
---



3,108.35

16,115.35








TABLE C. Summary Of Actual Catch And Effort Data For March, August, September,
October, And November 1976. Trap Day (td) Is Defined As One Trap
Fishing A 24-Hour Period.


Number Total Trap Average
Legal Weight Number Number Number Day Legal Catch Income-
Date Lobsters (lb.) Shorts Lobsters Fish (da.) Per td(lb.) ($)


March 803 1,162.0 259 1,061 13 2,700 0.4304 $2,033.50

August 407 486.5 1,525 0.3190 851.38

September 214 272.0 424 538 25 1,805 0.1507 476.00

October 1,199 1,241.0 342 1,541 38 2,220 0.5590 2,171.75

November 1,671 1,835.5 748 2,419 35 4,214 0.4356 3,212.13

TOTALS 4,294 4,997.0 1,773 5,559 111 12,464 $8,744.76

Average Catch 0.3789




TABLE D. Summary Of Costs And Returns For A Small Boat Spiny Lobster Fishery.
No Estimate Of Marketing Costs Has Been Included Because This Would
Be Highly Variable, Depending On Where The Fishery Was Based.



Item Year 1. Year 2 Year 3


Total Costs $ 27,075.35 $ 15,115.35 $ 16,115.35

Gross Return 40,921.20 40,921.20 40,921.20

Net Return 13,845.85 25,805.85 24,805.85

Return Rate 1.15 2.15 2.07
r


LITERATURE CITED


Richard, J. D., 1971. Delayed release device for
J. Conx. Int. Explor. Mer. 33(3): 492-505,


use in trap fisheries.




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