& )renews W
newsletterr of the JUCrW/SSC
Sirenia Specialist group
NUMBER 4 OCTOBER 1985
HELENE MARSH NEW SIRENIA SPECIALIST GROUP CHAIRPERSON
It is with great regret that we announce the resignation of
Robin Best, leader of the Amazonian manatee project in Manaus,
Brazil, as Chairperson of this group. Robin was responsible for
the recent re-establishment of this group, which then led to the
establishment of this newsletter. The new Chairperson is Helene
Marsh of James Cook University, Townsville, Australia. In the
following guest editorial, she summarizes some of the results of
the recent workshop in Edmonton and offers some thought-provoking
proposals for the group's future directions.
WHERE DO WE GO FROM HERE?
This past August, the first Sirenian Workshop was held in
Edmonton, Canada as part of the Fourth International
Theriological Congress. The Workshop consisted of an inspiring
and provocative opening address by Daryl Domning, a poster
session during which more than twenty high-quality posters
provoked considerable interest and discussion, and an afternoon
of comprehensive review papers. In all, contributions were
received from scientists from nine countries. The Workshop was
scheduled to conclude with a round-table discussion entitled
UNION INTERNATIONAL POUR LA CONSERVATION Of LA NATURE ET DE SES RESOURCES
n INTERNATIONAL UMON FOR CONSERVATION OF NATURE AND NATURAL RESOURCES
Commission do la suvegarde des esp6 es-Species Suvival Commission
Sirenews is edited by Daryl P. Domning, Dept. of
Anatomy, Howard University, Washington, D.C.
20059 USA. It is supported by the Species Survival
Commission of IUCN, the U.S. Fish and Wildlife
Service, and the U.S. Marine Mammal Commission.
"Where do we go from here?". I thought that the discussion rather
faded out; we had all had too much by then. However, I keep
thinking about this problem what can we of the IUCN Sirenia
Specialist Group do to facilitate the effective management of
The Edmonton meeting also provided the opportunity for Gren
Lucas and Bob Scott of IUCN to meet the chairpersons and deputy
chairpersons of a number of the IUCN/SSC Specialist Groups both
individually and collectively. At these meetings, there was much
discussion about methods of devising a series of objective
criteria by which members of a Specialist Group could assign
priorities to different projects. The intent is to use this
mechanism to help Specialist Groups communicate their concerns
and considered judgments in an effective way.
Many Specialist Groups are responsible for advising IUCN
about a large number of species with numerous isolated
populations. This can make the determination of priorities
complex, controversial and potentially divisive. The situation
with respect to the Sirenia is comparatively simple, perhaps
deceptively simple. There are only four species and all are
considered vulnerable to extinction. I am not aware of any
objections to the policy of the group which drew up the Sirenia
Section of the "UNEP Global Plan of Action for the Conservation,
Management and Utilization of Marine Mammals". This group decided
that support was needed for fundamental research on sirenian
biology as well as status surveys. Sirenian biologists also seem
to be unanimous in giving the highest priority to research on the
least studied species, the West African manatee.
However, there is potential for conflict about how to assign
priorities to the areas or countries in which status surveys
should be undertaken. The four species of sirenians collectively
occur in 90 or so countries, of which only Australia, Japan, and
the United States are classified as developed. There are never
going to be enough international funds to finance work in all
these countries. How should we assign priorities?
I asggzst tba tbh mQat ilmpQtant QriteriQn gbQuJld ba Lim
QZpressioD Qt iatrmest iram nfltiQfdlM Qf lbr QUfntlty Qfnlerfed
wbQ are in a PQgiti.Qf to aasiat in t12e iaPEmffntAftlQn Qg a
management aJan once it in MeYe12ped.
Although it is theoretically possible to assign priorities
based on what is known about the stocks and on the likely
logistical problems of carrying out a successful survey, it is
very difficult for an outsider to evaluate such information. In
particular, anecdotal information on the abundance of sirenians
is often unreliable.
Sirenians are generally cryptic. My experience suggests that
they are usually less rare than the locals think. The most
dramatic example of this comes from Moreton Bay, adjacent to the
major city of Brisbane. The general consensus in the early 1970s
was that the dugong population of Moreton Bay had been
irretrievably depleted by extensive exploitation for meat and oil
around the turn of the century. The results of the first
dedicated dugong survey of Moreton Bay in 1976 were a pleasant
surprise. A huge herd of some 200 dugongs was seen congregated in
clear water over white sand not ten minutes' flying time from
Brisbane International Airport. Clearly, it is inappropriate to
make assumptions about the likely abundance of sirenians without
proper surveys and, alas, there are very few places where that
has been done.
It has also become obvious that even with an intensive
survey effort, it will not be possible to rpoye whether a given
sirenian population is increasing, decreasing or stable for many
years. The recent work on the life history of dugongs and
manatees has confirmed that they are long-lived animals with a
low reproductive rate. No sirenian population is likely to
increase at more than about five percent per year, even under
optimum conditions of recruitment and survival. Furthermore,
because of the patchy distribution of the animals, it is
prohibitively expensive to obtain precise indices of abundance.
For example, recent surveys for dugongs in Australia have been
carried out at an overall sampling intensity of about seven
percent. The resultant minimum population estimates have a
precision of only about 18 to 20 percent. I calculated that an
exorbitantly expensive sampling intensity of over 50 percent
would be required to increase the precision of these estimates to
10 percent. The combination of probable low rates of change and
imprecise population estimates means that it will be a long time
before we can reliably track trends in numbers. There is no point
in waiting until we can prove that there is a problem. Effective
management programmes need to be developed now.
So what can we do? I believe that the Sirenia Specialist
Group should give high priority to educating influential (and
potentially influential) nationals of as many of those 90
countries as possible about the need to manage their sirenian
stocks. Once the appropriate local officials are convinced of
this need, we can offer advice and expertise if required.
There are a number of low-cost ways of facilitating this
education process. There are now several good films about
sirenians. Perhaps we should be investigating the cost of making
them more accessible to people who do not speak English. It is
important that sirenian researchers communicate results of
importance to management through popular as well as scientific
articles, and that some of these popular articles be in languages
other than English. The development of personal contacts is also
potentially valuable. Please take advantage of every opportunity
to develop such contacts. A one-to-one interaction is always the
most effective way of stimulating interest and concern.
And when you have developed your contacts, please do advise
Daryl Domning so that he can add their names to the mailing
list of this newsletter. Helene Marsh
NEW SiBSEWS DISTRIBUTION POLICY
The IUCN Species Survival Commission has proposed the
setting up of a central office for distributing copies of
Specialist Group newsletters to individuals, libraries, and media
organizations requesting them. The recipients would be charged a
fee to cover the cost of printing and mailing the newsletters. In
our case, I anticipate that this would mean that libraries
presently receiving Si newa would be asked to subscribe, at a
price yet to be determined. Individuals presently on the mailing
list would continue to receive Sintaw free, at least for the
foreseeable future. Additional persons or institutions wishing to
receive it would probably be encouraged to subscribe through the
central SSC office, unless this would be impractical due to
currency exchange rates or otherwise impose a hardship.
The editorial in the first issue stated that itDwn was to
be an informal forum rather than a citablee" publication. This
policy will continue. The proposal for a potentially wider
distribution, however, raises the question of whether the sort of
communication we wish to carry on in Sienea would be
appropriate in this more public setting. Although some sensitive
and controversial topics have been broached in these pages, my
personal feeling is that we have nothing to lose by obtaining a
wider readership, nor should we alter in any way the tone or
emphasis of the newsletter's contents to cater to a more general
audience. This is and should remain the newsletter of and for the
sirenian conservation and research community. The sole
implication of wider distribution is that contributors should
bear in mind that the information and opinions they submit for
publication will be more widely disseminated than formerly. The
caveat against quoting statements in izangwa without the
author's written permission would be repeated in each issue under
the new policy, and I hope this distribution policy would not
discourage contributors from expressing themselves as openly as
they have in the past.
It is not yet certain when or if this new policy will go
into effect. I would welcome comments from readers, particularly
as to whether they would feel more reticent in contributing to a
more widely read newsletter. DPD
El2eti2 oQf Maajth e Habitat. In March 1980, the U.S.
Fish and Wildlife Service (FWS) approved a Recovery Plan
identifying actions needed to protect and manage West Indian
manatees in Florida and Puerto Rico. Among the highest-priority
actions recommended were efforts to acquire and protect areas of
essential habitat. During the past several years, cooperation
between FWS, the State of Florida, the U.S. Marine Mammal
Commission (MMC), and The Nature Conservancy has resulted in
substantial progress towards meeting this need. A network of
federal and state refuges and reserves now includes much of the
habitat essential to the subpopulation of manatees which winter
along the west-central coast of peninsular Florida.
Reasons for concentrating on this part of the coast are
several: First, a larger number of manatees (over 120) depend for
winter habitat on the natural warm-water springs at the
headwaters of the Crystal and Homosassa Rivers than on any other
natural warm waters in Florida. Second, under the direction of
Galen Rathbun and, more recently, Tom O'Shea, scientists with the
Gainesville Field Station of the FWS Denver Wildlife Research
Center have built upon Daniel S. Hartman's pioneering research to
provide a better understanding of the ecology and demography of
the Crystal River/Homosassa manatees than exists for any other
sirenians. Their data on summer and winter habitat use suggests
that the most intensively used habitat lies in the mouths of
coastal rivers between the Suwannee River, about 40 miles north
of the Crystal River, and the Chassahowitzka River about 20 miles
to the south. Third, this group of manatees appears to be a more
or less discrete subpopulation and is the only group in Florida
known to have increased in size in the last several years.
Fourth, important summer and winter habitat for these manatees
includes areas that are relatively undeveloped compared to most
other parts of coastal Florida. Fifth, a number of coastal
refuges and reserves already exist or are being developed. The
60-mile stretch of coast between the Suwannee and Chassahowitzka
Rivers includes four National Wildlife Refuges, two State
Preserves, a State Aquatic Preserve, a State Park, and several
proposed state land acquisition projects. Although the existing
protected areas do not include many of the areas most used by
manatees, they do provide a substantial basis for maintaining the
integrity of the region's broader coastal ecosystem. Finally,
there is considerable state and federal interest in expanding
habitat protection in this area prior to the onset of intensive
development, which seems inevitable in the coming years.
To help establish a regional perspective for manatee
conservation, FWS and MMC cooperated to support the development
of a "Proposed Research/Management Plan for Crystal River
Manatees". This plan, which was prepared under contract to FWS by
Jane Packard [see SirRneys No. 1], was recently completed, and
FWS is now carrying out its recommendations. Besides providing a
comprehensive overview of available information on the regional
manatee subpopulation, the Plan identifies long-term needs for
both research and management. The Plan was complemented by a MMC
report entitled "Habitat Protection Needs for the Subpopulation
of West Indian Manatees in the Crystal River Area of Northwest
Florida". Completed in September 1984, this report compares
information on essential manatee habitat with information on
available habitat protection programs, including regional refuges
and reserves. Based on these assessments, it presents
recommendations and priorities for expanding the coastal network
of state and federal protected areas to incorporate the most
essential habitat areas. The MMC report, which was provided to
FWS and the Florida Department of Natural Resources, gave highest
priority to actions along the Crystal, Suwannee, and Homosassa
Regional cooperation in habitat protection has progressed on
several fronts. The most important winter habitats in this area
are the headwaters of the Crystal River (Kings Bay) and the
Homosassa River (Homosassa Springs). To prevent development on a
number of small islands in Kings Bay, which could have posed
threats to manatees by increasing boat traffic and water-related
recreation and degrading water quality in the warm waters
directly adjacent to the islands, The Nature Conservancy raised
funds to acquire and set aside the islands in a natural
condition. This was done in 1983, and in 1984 the Conservancy
transferred the islands to FWS, which incorporated them into the
National Wildlife Refuge System as the Crystal River National
Unlike Kings Bay, the headwaters of the Homosassa River
consist of a large spring which empties through a narrow spring
run. The surrounding land is largely undeveloped except for a
small area adjacent to the spring, which is operated as a "nature
world" featuring a floating underwater viewing pavilion. The
owner of the facility recently expressed an intent to1 sell the
property and, as a stopgap measure to prevent intensive
development, Citrus County purchased the 150+-acre site in 1984
[see Sir.anws No. 31. The County would now like to transfer the
property to the State of Florida, and the latter recently added
the site to a list of recommended state land acquisition
projects. A net stretching across the mouth of the spring run
prevents access to the actual spring by manatees; however, three
captive manatees are presently on display around the underwater
viewing station. Should the State acquire the site, it would have
outstanding potential as a public education and interpretive
center as well as a preserve for protecting vital manatee
Perhaps the most important summer habitat in the region is
the lower Suwannee River. A maximum count of 33 manatees has been
reported by FWS in this area, and the maximum level of seasonal
use probably exceeds this count. Most of the uplands and wetlands
surrounding the lower seven to ten miles of the river are
included within the boundaries of the proposed 56,000-acre Lower
Suwannee National Wildlife Refuge. In the last several years, The
Nature Conservancy, the State's Suwannee River Water Management
District, and FWS have cooperated in acquiring about 37,000
acres of this total.
Two additional areas of extreme importance are the lower
Crystal and lower Homosassa Rivers. These areas, which are still
relatively undeveloped, are essential travel corridors for
manatees moving to and from the warm-water winter refuges at the
heads of the two rivers. They also are used during winter warm
spells, when manatees frequently move downriver to feed. Finally,
these areas are used during the summer by a small but significant
portion of the population for feeding, cavorting, and mating. As
a step toward protecting the shorelines of the Crystal River, the
State began in the early 1980s to acquire a large tract of land
along the upper and middle portions of the river. In 1984,
however, both the State Bureau of Land Acquisition and MMC
independently developed virtually identical recommendations for
acquiring wetlands and uplands along the lower, as well as the
middle, portions of the river. As a result, in early 1985, the
State placed this new acquisition project (entitled the Crystal
River State Preserve) on its land acquisition priority list.
Although listing alone does not guarantee acquisition, it is an
essential first step.
Habitat protection efforts along the lower Homosassa River
are not so far advanced; however, one possible approach would be
to expand northward the northern boundary of the existing
Chassahowitzka National Wildlife Refuge, which lies just south of
the river. MMC recently recommended to FWS that it evaluate and,
as possible, acquire undeveloped wetlands and uplands along the
lower Homosassa for incorporation into the Chassahowitzka
These cooperative and complementary steps by federal and
state agencies may offer the best hope for the long-term
protection not only of manatees, but also of the many other
species of fish and wildlife indigenous to the coastal region.
Indeed, this ambitious approach has, as its ultimate objective,
protection of the region's coastal ecosystem of which Crystal
River manatees are but a part. Complementary federal and state
actions taken in the past two years provide a foundation for
achieving this objective. With persistence and luck, the habitat
required to support manatees and other coastal species will be
secure for future generations. David Laist (U.S. Marine
The following item was published in the Fort Lauderdale
(Florida) NHwaL/un Setzinel on July 31, 1985, and reprinted in
abridged form in the Florida Department of Natural Resources and
Florida Audubon Society's SAye the Manateg Club Mewa (October,
1985), whence it is here quoted with permission:
bQut Sal.n Commercial Ehabermaun QiYn Elison Tram Qr
Killing a Manateg. A South Florida man on July 30, 1985, became
the first person in the United States ordered to federal prison
for butchering a manatee.
Ignoring a plea deal that called for no jail time, U.S.
Magistrate Ann Vitunac sentenced Jimmy Malmsten, a Port Salerno
commercial fisherman, to six months behind bars and a $750 fine.
State and federal courts have levied fines against people
accused of killing manatees, usually by riding over them in
propeller-driven boats, but officials said Malmsten is the first
to be sent to prison.
Malmsten pleaded guilty last month of possessing manatee
meat when he was stopped by Florida Marine Patrol officers May
16, 1984, in the St. Lucie River in Martin County. He admitted he
carved the harmless animal for its meat, but said the death
itself was an accident, occurring when his boat hit it in pre-
Malmsten was charged under the Endangered Species Act after
Marine Patrol officers noticed chunks of meat floating in the
water behind his boat. He could have received up to a year in
prison and a $20,000 fine for illegally possessing a manatee
Prosecutors agreed to a suspended sentence and $750 fine,
but Ann Vitunac ordered that Malmsten serve six months in a
federal prison after she learned of repeated fishing and boating
violations on Malmsten's record.
According to court records, Malmsten had been arrested five
times since 1980 for violations ranging from illegally taking
snook with a net to speeding in an idle zone and careless
operation of a boat. Vitunac noted that the speeding charge came
only two days after the manatee incident.
[The SAye the 3aflxaee t iab UrneM commented on the above story
that "This was a combined effort of several government agencies
working in cooperation with the judicial system. They are all to
be commended for their dedication and perseverance." i~taeSS
adds to this its commendation of all concerned for setting a
welcome example of law enforcement.]
LQao S BepfiiAShbmalit 2jagt. MEPA (the Meteorology and
Environmental Protection Administration) of the Kingdom of Saudi
Arabia is planning to establish and develop a program to conserve
the endangered Arus-al-bahr or dugong in the Saudi Arabian waters
of the Arabian Gulf and Red Sea. Arus-al-bahr, the Arabic name
for the dugong, means "bride of the sea" or mermaid. By
invitation from MEPA, I visited Saudi Arabia in February 1985 and
prepared a work plan and report for a research program to
determine the status of dugongs in Saudi Arabian and adjacent
waters. Part of the report included a summary of available recent
information on dugongs in Saudi Arabian and adjacent waters.
The present interest in dugongs by the Saudi Arabian
government results from investigations made during and following
the disastrous Nowruz oil spill in 1983 and 1984, when huge
quantities of oil spilled into the Arabian Gulf from war-damaged
oil wells in the Nowruz Field located in Iranian waters [see
iLE.D.M. No. 1]. MEPA reported that 36 dead dugongs were found in
March and April 1983 along the Arabian Gulf coast of Saudi
Arabia. An additional two dead dugongs were reported from Bahrain
during this time. [In July 1983, Begley %t al. reported 53 dugong
carcasses beached; see Recent Literature section below.] It was
not established what actually killed these dugongs and other
marine life, which included fish, sea snakes, marine turtles,
dolphins, and one whale, and it is not certain that these kills
were even a direct result of the Nowruz oil spill, as the kills
preceded the actual arrival of oil from the Nowruz wells. It is
not known if more than the above 38 dugongs were killed, nor was
the size of the Arabian Gulf dugong population known, although
MEPA referred to a 1979 estimate of 50 to 60 dugongs for the
Arabian Gulf. This most likely was an estimate for the Arabian
Gulf waters near Bahrain (Gulfs of Bahrain and Salwah). Because
of the large numbers of dugongs known to have been killed, the
MEPA assessment was that following the Nowruz oil spill, the
Arabian Gulf dugong population had probably been reduced to a
dangerously low and possibly non-viable level and could become
extinct, and that dugongs from elsewhere (e.g., the Red Sea)
might have to be reintroduced into the Arabian Gulf in order to
maintain dugongs as part of the Arabian Gulf fauna.
Dugongs are still present in the Arabian Gulf, although they
are threatened by oil and other pollution, habitat changes (land
filling and dredging), and accidental capture in monofilament
fishing nets. There have been sightings of live dugongs reported
from the Arabian Gulf during and since the Nowruz oil spill. MEPA
observers sighted two live dugongs in the Gulf of Salwah in late
April 1983. There is an as yet unconfirmed report that 30 live
dugongs with a couple of calves were sighted off the United Arab
Emirates in October 1983. During a 2-1/2 hour helicopter flight
on 18 February 1985, covering the entire length of the Gulfs of
Bahrain and Salwah, I saw one dugong between the Bahrain and
Saudi Arabian coasts. From September 1984 through January 1985, 8
separate sightings of 1 to 70 dugongs have been reported to D. H.
Vousden (State of Bahrain Environmental Protection Organization),
with the largest group, more than 70 dugongs, seen on 12 January
1985. Seventy dugongs had also previously been sighted in Bahrain
waters in November 1983. Two dead dugongs were found on Gulf of
Salwah beaches of Saudi Arabia between January and the end of May
1984 by staff of the University of Petroleum and Minerals,
Dhahran, and a third dead dugong was reported but not located
during this period.
There is very little information on dugongs in the Red Sea.
An IUCN report on the distribution of habitats and species in the
Saudi Arabian waters of the Red Sea, done for MEPA, suggests that
dugongs only occur there in very low numbers. During the IUCN Red
Sea survey conducted from March 1982 to October 1983, only two
observations of dugongs were made (one live animal tentatively
identified as a dugong and one dead dugong). The IUCN report also
states that in 1983 two dead dugongs, a male and a female,
believed to have been collected in the Gulf of Aqaba, were
delivered to the King Abdul Aziz Marine Station at Sharm Obhur.
Dr. B. Albassam (King Abdul Aziz University, Jeddah) reported
that in 1974 two dugongs were reported in the Red Sea region, one
from the Farasan Island region and the other from the Gulf of
Aden. In October 1984, 20 animals, probably dugongs, were seen
from a helicopter in a shallow bay in the northern Red Sea east
of the mouth of the Gulf of Aqaba during a MEPA coastal habitat
survey. Although there is a paucity of dugong sightings and
records for the Saudi Arabian waters of the Red Sea, it is
possible that with its large areas of seagrass beds, some in
isolated regions, the approximately 2000 km-long Saudi Arabian
coast of the Red Sea could contain large populations of dugongs.
The available information shows that while dugongs are still
present in the Arabian Gulf and Red Sea, their numbers and
distribution are not known. Comprehensive and careful aerial and
other surveys of both regions, which MEPA plans to carry out, are
required as the first step in establishing an Arus-al-bahr or
dugong replenishment program. George Heinsohn
The D2igsratYQ Ziegy and 91fialaDQY Qf tbQ Wgt Indian
ManteSA Trichechus manatus (Douglas M. Burn). During the
winters of 1982/83 and 1983/84, the digesta from 8 West Indian
manatee (Trabch bua imnatua) carcasses were sampled sequentially
along the length of the gut. Samples were analyzed for dry matter
content, organic matter, crude protein, crude fat, acid-detergent
fiber, lignin, and cellulose. Apparent digestibilities were
calculated using the lignin-ratio method.
The voluminous large intestine of the manatee is responsible
for considerable water reabsorption, as well as being the major
site of organic matter, crude protein, crude fat, and cellulose
digestion. Overall digestibility coefficients for organic matter
(71.1%), crude protein (61.0%), and crude fat (77.3%) are
comparable to those of terrestrial herbivores. Manatees have one
of the highest digestibility coefficients for cellulose (79.6%)
of any mammalian herbivore. This high efficiency of cellulose
digestion is probably due to an extremely slow rate of passage in
concert with a less fibrous diet. [Abstract of a master's thesis
in Biological Oceanography submitted to the University of Miami,
Florida, in May 1985 and supervised by D.K. Odell.j
The following abstracts are of papers and posters presented
at the Sirenian Workshop of the Fourth International
Theriological Congress, Edmonton, Canada, Aug. 13-20, 1985.
THE PARAsITES OF SIRUNIANS. C. Seck. U. S. Fish and Wildlife Service, Cenver
Wildlife Research Center, Gaineanvile, Florida. USA 31b60, D. Sta itr. partmen
at Zoology, Univermity of Canterbury, Chtritchurch 1, tw Zealand, and G.-.
tathbun, U. S. fish and Wildlife Service, Oenver utldlif Research Center.
Gasneeville, Florida, USA 32609.
Ten species of pearseiee have been reported from masnsees: (our trematodes. one
Ristode one procoeo4n, one ccitode. and two accoperamitic rustsceean from the
eet% Indian man te*e. rchachus enatu. one tremode* one nematode, and one
pretotoan froee he Amaonian *&nLee inunute; and oie tr-eeClde, one
ntAl0de, end one cruitacean from the Vest African menatee, T. mneantns.
Several ofa the esoe parasite occur in all three specie, of manatete. [n
coAtreec peraltcli species have been described Irom dugongi, Puont dmS- n
1 tremades and one seacrid nlafleoe. The helmilths of mandates aret coonly
liountere, se is one crustacean (a barnacle), and an almrlto proLTsooan from
the Amaonian sanatee. The coatcde, a copepod, and a protoeson were s**n only
a.e in inivdual waft Indian manatees. Many of the dugong hIlminthe are
Zoo0ly recovered after close eaiination of a carcas'. however, the presence
o0 species varies by host range. Each of chese parmites are Listed
tccoreV4 to site within the iLrenian hboi And whenever posiLle, p4raNice
p1welalncet eta are included.
A Zcmpsr.Son of Differences in Behaviors of Captive-Born and Son-Cacive Samrn
'"anates (Trichechus tanacus) as a Measure of Adjustment to a Contained Natural
environment Barbara Bernier and John Morris, Florida insti uce of Technology.
A quallC tive and quantitative behavioral study, comparing a pair of male and
female :we-year-old captive-born manatees (Trictechus =anarus to nacural-born
manatles Of the same age class, was made to assess the ability of captive-born
a=ials to acclilate to a contained natural environment. This stzdy vas
oamducted in anticipation of the release of the captive-born ani-als i-to the
natural environment. A catalogue of 27 behavioral uni:s were dEfineo based on
general observacioni of anate*es. A behavioral unit consists of a core move-
an accompanied by typical but dispensable accessory v\-ements. FrTO the
;aralogus a ciecxshaar of thd bhavlors wjs designed. ObsarvatlonS wVre
recorded by a single observer in the water using norkel.lLng gear. Behavior of
a focal uaimal was recorded &a 30-second intervals during 30-minutf observation
periods. An Inter-Observer liability Test demonstrated 89% agreement between
do observers making simultaneous recordings on a focal. animal. following 79
hours of observation, no significant difference was found between captive- and
zatural-born maajntee in percent rime spear in various activitrjs. The data
c;llected establishes a baseline for future quantitative behavioral studies of
manactsi. Following the radio-tagging and release of the captive-borr juvenile
tall study will be Important in assessing the progress of acclimatisation of
these animals to the natural environment.
nMTALITY PA77ERI i4 MANATZIS FnO rFaRDA. .K. n ., T.J. O'.Lee. U. 5. r1st
en4 Wildlille service. Denver Wildlife Research Center, Gainesville. Florida. USA
32609 Aen D.K. Odell. loseansiel School of Mrtne and Atmospherc Sciences.
UniiVtiLy of HMiai. flet. florida, USA 33149.
a total of 613 Meat Indian manatees (Trtchechue manatu) wee recovered and
examined at nacroepy in Flortda from Jnutpry 197S through December (9$*. Prrbeol4
cause of death wve recorded and each case was placed into one of six major death
casegorils. The total numbre tof spectlen in each of the sil categories were:
callscion with boat or barge, 1823 (22.5Z)I crushed or drowned in a flood Ca or
isnal lock, 11 (6.3Z); other humn-relatod causes, 29 (3.6l); dependent celvee,
132 (16.2Z); natural. 95 (11.71); and ndeermnlled, 323 (39.7%). During the tno
vears that these date were clleatted several major treandl have became apparent.
li ty-e*ven percent of all mandate deaths aLrtbuted to entrapeont in tlood
control structures came from Dade County. HMre than 6S percent of Lhe deaths due
to col1eLona witch boats or barges occurred along the heavily human populated
resc coast of Florida. Due to very cold temperature. the tocal number of deethe
reported for che winters of 1977, 1981, and 1984 w"ce much higher than other
winters, and predominately affected younger, subadult mantee theti are more
susceptible to cold exposure and perhaps lack the experience to avoid cold *pells
iv seeking shelter in warm wateer refugiLs. Aid finally, the first recorded die-qit
of manatees involving exposure to red tide organisms occurred in Let County in
,-t --- .--- i-- -. -i f.k" ,.-. I ..t t7 aninals in le.. than three months.
DISTRIBUTION, STATUS AND CONSERVATION OF MANATEES IN MEXICO. L.C. Colmenero-R..
Department of Zoology, University of Mexico. Apdo. Postal 70-153, Cayoacan 04510,
Wear Indian manatees (Trichechus manatus) inhabit co*stal areas, estuaries and
associated rivers of southeastern Mexico, and the dicribuWtion is related to
cheLr need for warm water and the distribution of frmhwa ar and m uLierged
aquatic and marine food plants. Land survey and interviews were conducted CO
determine their status, distributton and conservation. Data wete collected from
March 1980 through November 1964. Illegal hunting is identified as the major
source of mortality and stricter enforcement of existing laws would help preserve
the remaining population. Manatees are protected in hexico under OffLciael Act ot
1981, &azett&d on October 30, 1981. There Is not one conser mtlon group of
consequence in Hexico in the actuality. The main Governmental Institution,
Socretarla de Demarrollo Urbano y EcoLogia (S.E.D.U.E.)., mould governmiuit
policies toward the envitronMent, and is behind manatc protection, and prepared
to do whatever it can to preserve the species. The most pressing immediate need
for manatee conservation is proper enforcement of the Officlal Act. An
environmental education campaign should make it possible to increase local
cooperation in enforcement.
THE SIRENIA9 PAST, PRESENT. AND THE FUTUIET Daryl P. Domning, Department of
Anatomy, Howard University, Washington, D.C. 20059 U.S.A.
The characteristics of the Sirenia aere established in much their present form by
some 40 Million year ago. They are strongly "K-adapted" and little able to
withstand heavy mortality from human or olher sources. Probably due to lack of
diversity in their food pLants, they have never become very diverse thwemseves,
and have remained anatomically and ecologically conservative. But they do not
lack evolutionary potential, as shown by the evolution of striking adaptive
novelties within the last 10 million years by each of the 3 Recent genera. Each
bkl ha a unique history vith unique implications for management. We researchers
must learn as much as possible about strlnians while there is ac1ll time, and
also msmk greater efforts to explore the relevance of strenian phenomena co the
teac of biology. At the same time, we bear the majot responsibility for
preventing their extinction, which could occur in our lifetimes. Human
population Irowth end habitat destruction must be stopped, for out own good and
thaC of other specLes. Natural systems must be permitted to function
iadependencly of human manipulation. Management Ctrategies mast be consciously
designed to preserve them not just for the next century but for thousands of
years to come. This is a moral Lmperative, but also necessary for both our
pfyLoatl survival eam our matal and spiritual health.
MAUATEE RMPOVSE TO A POWER PLANT SWUT-DOWN IN SOiUTRWSTEUII FLORIDA,
R. Kipp Frohllch, De~avr Wildlife Research Cancer, Cainesville, Florida, U.S.A.
32601. JMa M. Packard, Florida Cooperative Fish and Ptldlife Research Unit.
Universit Ga Florida, Geineeville, Florida, U.S.A. 32611.
Dependmace of arnatae (Trichechus mMantu) on artificial sources of warm water
durif l winter has been of cronc in areas where natural sources of warm water
have not been identified, such asu outhwetern Florida. The abundance and
distribution of manatees in Lee County wve monitored one year prior to and
during the temporary shut-down of a powrt plant. Aerial surveys were conducted
twice a *amth during the year and for 3 to 5 successive days following each
winter cold franc. Movents of 13 manatees wart monicord by radio telemecry
during the change in power plant operation. Manatees were found in the
Calooeahatchee River system throughout the year. although numbers increased and
distributlou shifted toward the power plant in the winter months. There was
no significant difference in manatee counts between the two winters (t 1.09;
24 d. f.; p 0.28). During the first part0of the second winter, manaees
aggregated in areas that were naturally 1-2 C wrmer han the unheated power
plant canal. The manatee returned to the plant as temperatures at the new
aggregation sites dropped to 160C and concurrently the power plant resumed
operation. Although maoatees found alternative temporary warm-water sites,
they were still dependence on the therml effluent during. Che coldest part of
ASUALSI5 O( 5TOHACN CONTWrS Op WST INDIAN MANAATE CA CASSES SALVAGED PFOM
IMAMG ANO DUVAL COUNTIfS, FLORIDA. L.A. Hurst, Florida Cooperative riskh nd
Vlldilfe Relearch Unit, Univerltty tr Florida, Olaneeville, Frlrida, UlA 0ll11
Wmd C.E. Cethiun, U. 5. Fteh ind Wildtlif Service, Dnver Wildlife research
Center, Gtineeville, Florlda USA 32609.
Frequency Occurrenae sod percent compoStit *if feed items in West Indian
aetee (TrtehechSh menatul) stomachs froee revard and Duval Counties. Florida,
were documented. Haatee itenmahe collected free salvaged carcasecs were
lwy4Sd MelnIg a mo6Lfted esterospe point teehnlque. Fragments of marine and
froehueter m erophytes were Itetitled mteroecopically to lenes, while algse,
rhiasmes, end grassee were recorded so separate categories. Results of this
study will be discussed in term of conetrvwtion iaplicatiano Li the two
ENTRYY OF OBSERVATIONS OF SIRENIAN BRAINS. .. I. Jorns:.,Anatcry
-.partment, Michigan State University, East Lansing, Micn-.gar.,
5. A. 48824; R. L. Peep, Department of Physiological Sciences,
-*.;versity of Florida, Gainesville, Florida, U. S. A. 326:C; and
:. Welker,Department of Neurophysiology,University of Wiscons:n,
adasc., Wisconsin, U. S. A. 53706,
~re actual number of observations, in the past 120 years, of
strer.afn brains, is few enough that we can present virtually all of
t.nen -%ere. The earliest illustrations were the sketches of manatee
trains shown by Murie (1872), Chapman (1875) and Garrod i1877(.
~K1io0no-Maicay (1805) showed the first sketches of a dugong brain.
wur;e in 1885 published beautiful drawings of a manatee train,
snowlnq morphology and vasculature. More sketches appeared, of M.
.nun js by Bedderd (1897), of T.manatus by Elliott Smit. 119021,
n of dugong by Hill 11945) Kodern standards are met i. studies
f duqong: spinal cord by Dexler and qer (1911), and brain by
:exler: 1913), with excellent photographs, and photomicrograpns of
stained sections. Photomicrographs of sections from mar.atees were
snow my Jelgersma (1934); these were improved by Verhear: (19721.
r:.ar.t (1954) shows a photograph of a brain of K. inunq;.s. The
nexti studies are ours, and we present casts and photograp,-s of
::.e ::aLn of Trichechus manatus, and photomicrographs of sect::=r.s
:f special Interest. [Supported my NSF grant BRS 850368-.
THE STOMACH OF TRICHECHcUS A..SA S5 A COMPARISON WITH OTHER .MA'kLALIAN HERBIVORES.
Peter Langer, jns:ztt f. n .r!e & Zytobiologie, Jusrus-iiebig-Unlvecsicrc,
Aul.we 123, D-6300 Ziessen. Fed. Rep. of 3ermany.
The stomach of T:I'checus ti-aa:us, the Caribbean manatee, is an organ with an
off-set gland that has proper gast:Ic gland mucosa. The stomach is very muscular
and has a massive pylorus, wh2ch La followed aborally by a voluminous duodenal
stpulla of approxi-ately the sae size as the stomach proper. Two diverticula
branch off from thoe uodenal aspulla. In semisch Eatic illustrations the
different steps of gastcri digestion in the manatee are compared with those of
pig, ruminant, and hippopotamus. In the manatee salivary anylolysis and
proteolysis take place one after the other. The voluminous duodenal ampulla
gives sufficient volue to allow removal of contents from the stomach and a start
of another feedlin bout after a period of non-feeding activity.
coUICZDfNCE BfTWEWf THE SEASONAL ZPATERNS OF SEACRAS3 CGuoW DEWTIZYAL GROfW
LATER DEPOSITION, AND CALVING IN THE DLUGONG. J. Canyon Departments of Zoology,
masot University, Melbourne, and James Cook University, Townsville, AuctralLa,
amd H. Marsh, Department of Zoology, James Cook University, Townmville,
In the 4ugong, dentinal Growth Layer Groups (GLGa) consist of a vide zone af
latereTisLte optical density containing numerous faint accessory layers followed
by a relatively narrow zone in which the layering is enhanced. Study of the
seasonal pattern of deposition of these GL=e in the tusks of 106 dugongs from the
Townsville and Mornington Island artes of Worth Queensland Lndicates that one GL0
to deposeted each year, formacion of the narrow zone generally occurring from
July to October inclusive. Photographic and coring techniques have been employed
to monitor changes I seagrass blosaes, density, speciLe composition, and
nutrient levels along permanent transects at three study sites where dugongs feed
la the Towmnville area. Results to date indicate a significant drop In btomage
through the winter months, with regrowth at the oneet of spring in Septesber.
These results suggest that the pattern of GIG deposition may reflect nutritional
status. SeagrTss. regeneration also coincides with the onset of calving, most
births occurring from August-September through December.
IMPIOVYIG DUGONG AERIAL SURVEY TECOiQUE. H. Marsh, Department of Zoology. Jaes
Cook University, Townsville, Australia.
Dug@Wa occur along sae 15,000 im of coastline in northern Australia. Aerial
surveys, based on the technique developed by Caughley to census kangaroos, are
being used in an effort to obtain precise indices of the relative density of
dugangs in different resas as a basis for monitoring population trends., Survey
design is being Laproved by comparing the precision of the population estimates
obtained with diftferet lev*L. of survey intensity. Analysis of variance is
being used to compare densities of dlugongs observe under different experimental
combinations of survey height and transjct width, and with difference incnsittes
of glare off the surface of the water. The counts of Lndependent tandem
observers sitting behind each other on the seam side of the aircraft are being
compared to develop factors to correct for the number of 4ugons groups visible on
the transec line which are missed by an observer. Vertical -aerial
photogrammtry of dugong groups in clear watte is being used to develop
confidence intervals for the proportion of dugonga which are below the surface,
The results of this work to dats will be presented.
OCCURRENCE OF DUGONGS IN OFFSHORE WATERS. H. Marsh, Department of Zoology, Jeass
Cook Unive4w ity, Townsville, Aust.alia.
Recent serial surveys in northern Australia indicate that dugongs nay use
offshore habitats Much more than had been Supposed. During a survey of the
Tortes Strait area in I ovembel 1983 along a settls of parallel xauecta, only
about 20% of sightings were within about two a= of Islands or reefs. In November
1984, the water of the Great carrier Reef lagoon between 14* 10'S and 15* 15'S
were surveyed aloga a series of esat-west transects (approximately perpendicular
to the coast). Dugongs (Including calves) vwre sightae up to 55 i ftrom the
coast, and using surface sighLtings a an Lndex of relative density, it was
estimated that more than 601 of dugongs in the arta were greater than 20 kn from
the coast at the CiLe of the survey. Dugongs were sighted in inter-reftal areas
in waters up to 20 to 30 a deep. Although dugongs may eheliter offIshore during
daylight hours as a behavioural response to hunting pressure In the 'Tortes Strait
area, this is an iplausibli explanation for their observed distribution in Great
Barrier het wa s.
POrULATI0 BIOLOGY OF S$ItiIAu IfMLICATIONS FOR CONSERVATION N. Harsh and L..H.
Harsh, Departaents of Zooloey and Mathematics, James Cook Univert .y, Townaiwrtl,
Informatioa on the life history of the West d41ian HMantee obtained by direct
observtion In Florida indicates that females can become sexually-asture as early
as four years old anad that Mature males glve births every two or three years.
Gestation period is 12 to 16 months, and the usual litter size one. Twins are
occasionally seen In contrast, information on the life history of the dugong
obtained from careast analysis is northern Australia, uggescts that females to
not become sexually-maturl before they are noin years old (and sometlien not
until age 15-17) and that nature females give birth every three co seven years.
The gestation period and litter size are similar to cthoe of the West Indian
mates. There are no reliable age-specifie mortality or fecundity data
available for either speclei, although aMbers of both my live for 50-60 years.
A series of simple population models will be developed for a range of
prt-reproductive periods, calving intervals and hypothetical mortality schedules.
The implications of the results of these moels for conservation will be
a iScLuITE-atlOHED uSAD ThG fiACKS TtE OVTStv s or A MAOItZ 1S TLOuIDiA.
Mace3. et. Hatfield Marine Science Center, Oregon Scstate University. Nevport,
o*eg:= 97365 and G.5. Rathbun, U.S. Fish and Wildlife Service, Denver Wildlife
Research Canter, P.0. Box 70, San Simon, California 93452
In February 1985 a West Indian manatee (Trichechus ma Aul) was radio-tagged
wit- a 401.650 HHf cransmitter monitored by Argeo Data Collection Systems
on beard polar-orbiting NAA satellites. The radio floated in a cylinder
andac was attached by a 2s tether to a belt aroucJ the peduncle. Locations of
the manatee were calculated from doppler shifts resulting from the satellite
aoveat. The cranaicter's temperature and Suemaries of its attitude were
sct: once each aiauce. During the first two webos, the nnatee was captive
12 a 4 acre area and locations were consistently within 500m. A* aeny ms b
locations have been acquired in a single day. At this wrLtini the radio
h4s provided movement and teleaItered information for 43 days froze both fresh-
and salt-water areas.
ESTIMATING AGE OF YOUNG $EST INDIAN MANATEES. TRIECHUS KA'NLTUS,
FROM DENTAL LAYERS. A.C, Myrik, Jr., NMFST 2/1, La
Jolla, California, U.S A"
Despite the problem that the teeth of manatees are continuously
replaced by newly formed teeth erupting from the rear of the jaw,
dentinal and cenvntal growth layer groups (GLGs) continue to
accumulate until a tooth is lost anteriorly. All teeth formed
Ana being formed at the time of birth exhibit a neonatal line in
the dentine, but a neonatal line is Absent in teeth formed after
parturltion. The number of dentinal GLGs in any tooth with a
neonatal tine will represent the age of the animal from whicn it
was taken. A count of iLGs from a tooth containing no neonatal
line will represent the age of the tooth and a minimum age of the
animal from which it was taken. Maximum ages of older animals may
be estimated using GLG counts from periotic bones. These
observations are based oo material from 12 specimens inludrn; a
twice tetracycline-labeled animal.
BRAIN-BODY WEIGHT RELATIONSHIPS IN SEA COWS
Thomas J. 0'Shea and Roger L. BRee U.S. Fish and Wildlife Service, SireUia
Project, 412 NE 16th Ave., Gainesville, FL 32609 and Departent of Physiological
Sciences, College of Veterinary Medicine, J-144, JHMIHC, University of Florida,
Gainesville, TL 32610.
Much recent work has centered on the topic of relative brain size in ma-mals.
Comparative studies to data have typically not included the Sirueat, however
sireniaus are an interesting outlying group in terms of eacephalizetion, with
brain sizes auch smaller than would be predicted on the basis of body size
using the average samalian plot. We have directly determined brain and body
weights for over 30 West Indian manatees. E.Q:a range from about 0.03 to 0.08
In the 10 adults from our sample (1 0.06 1 0.01). some of the lowest values
of all living mammals. We calculated E.Q. values of about 0.07 for dugaongs.
using data published by Japanese investigators. Stcller's sea cows were also
characterized by low E.Q.'s. In addition to these recant forms, fossil sirnilane
also had small brain. Unlike the Proboscideana, which have evolved relatively
large brains, the ireniane have retained the small-sized brains typical of
their basal anceators. We discuss the possible importance of metabolic rate
and other physiological. developmental, behavioral and lila history character-
istice of the StreaU in relation to brain sle.
FrGL.E MPRING0 UMAVIOR IN VEST NDOIAN IMNATZS. T.J. O'Shea. U. S. Fish and
Wildlife Service. Denver Wildlife Sesearch Center, Geonesvlle. Florida, USA
3260a and S.H. Shame, Caster for Martne Studies, University of Californi. Se, nt
Crus, Ctlifornia 950,6
Nether-younf pairs ef mantees (fTrtchechus enatus) were observed at Blue Spring
sun an the centiguous St. Johnbe lver, Florida. Techniques included
lansIaceInes6e sampling of behavior of II pe*ts at the clear spring over winter
0eeon. ratletrcking of fIeaesI with calves or tbetr Independent offepring
during waer sesmens, and underwater sound recording. Fairs usually keep within
Is part, and nursing bouts of 3 *ta durettae occur every *f2 main. The period
of a tritlonal dependency varies free 1 to 2 years, but correlates of chts
variation are unknown. Calves range from 210 to 260 cm total length as weantis.
Individual recognition occurs between cows and calves, probably based aon
vocalsations. and a variety Of evidence euUgestA that recognttion persiste
beyond weaning. Young of both gases occupy the maternal range when Independent,
and dieper6al from the study area has not occurred In offspring as old sa 7 yr.
N al phslopatry, long Lerm kin recognition, and tradition my be of importance
tn ameliorating winter mortality.
ST&ATECIES FOR PROTECTION OF I4ON-EXPLOITED SIRENIA POPULATIONS. Jane M. Packard,
Department of Wildlife and Fisheries Sciences, Texas A & M University, College
Station, Texas, U.S.A. 77843. Patrick M. Rose, Florida Department of Natursl
Resources, St. Petersburg, Florida, U.S.A. 33701.
In protection of Sirenia populations that are not traditionally exploited, the
major issues include (a) reduction of human-related mortality, (b) reduction
of harassment indirectly affecting the population, (c) alteration of habitat
and (d) the difficulties involved in monitoring population changes. After
briefly reviewing the relative importance of these issues world-vide. we will
focus on the strategy used in protection of che West Indian manatee (Trichechus
manatus) in Florida. Although federal and state laws provide Legal protection
and som funding, the implementation of protective measures on a local basis
has been difficult. Development of non-legislative programs has been
instrumental in raising state funding, public awareness and local support for
measures such as slow boat speed zones, sanctuaries at warm-wacer refuges, and
redirection of water-front development. These non-legislative solutions have
included public education, clubs, volunteer patrols, industrial funding.
land-use planning, statewide and site-specific research/management plans. This
strategy is briefly compared with strategies used in other nations for
protection of Slrenia.
eS% STATUS OF THE WEST AFRICAN MANATEE IN THE GAMBIA, WEST ASRICA
/ ?well. James A.
University of Washington, Seattle, WA
There is lictle available information on the status or biology of the West
African manacte (Trichechus senetalensis). This study was conducted in
Senegal and The Gambia to obtain data on chair distribution, general
biology and habits, and to assess the potential impact of a proposed series
of dams on the Gambia River. This investigation concluded that West African
=anatees, like West Indian mandates, are found along the coast, in estuaries
ani iar up rivers. They require calm waters, access to freshwater, and
adequate food. In estuaries they frequent sources of freshwater and feed
extensively on mangrove. The recent Sahalien drought has reduced freshwater
ru-.~ff which has resulted in a dilback of mangroves in ar.y rivers. Manatees
'ave disappeared from many of the rivers affected by the drourhL. The
;prpoaed dams will further reduce freshueter flow and w.il Limit the manatees
a:sesa to :ood during draew-downs. Even though they are protected they continue
:: be hunted by harpoon and nets. The cocoination of reaced root, limited
i:asht.ater and continued hunting may have a signilciant .npact on their
.- __ ^- - ?'.. J_.4- -- A 4_j4 1 4f Af ^ .r ., anr M p* rzr fltric t o I ^> t Fhei\r
DISTRIBUTION OF MANATEES IN fPUUTO RICO. C.A. ahbbun. T. Carr. and N.H. Carr,
florida State Museum, University of Florida, GaiLneMvlle, Florida. USA 32611.
The distribution of -enatees (Trachchus smnatue) around the Carlbbe*n island of
Puerto Rica was determined by flylng 19 serial surveys in a Cessna 172 airplane
from March through July 198t. Four of the surveys were of the entire island,
whale 15 were restricted to Viequee Island and Loosevelt loads Naval Station
(RiNS) in southeastern Puerto Rico. A total of 377 menatee sightings was made,
17 of which were calves (4.1). Over 41Z of the Sightings made during the four
entire-tland survey were found in the region of RANS. On the LRNS/Vlsques
sandd surveys, about 1/4 of the sightingse wre 0a the north side of Vilques and
2/1 at the elghtlngs were in the coves along the southern shore of the naval
station. The manet*ee feed on the rich *eagrass beds in the coves and drink
freshwater from a nearby sever plant f fluent. In Puerto lcoe, the naval
station erves as a de facto sanctuary for manatees, which to reflected by Eheir
ZMAVIOSAL ECOLOGY OF IIAWUIANE. GAs. tathbun an" T.J. O'Shea. U. S. Fish and
wildlife Service, Denver Wildlife Research Center. Gainevillle. florid, USA
A cofparleon of the Dugongitde and Trichachidee reveal that any aspects of
their behavioral ecology are similar, such 6 their low reproductive ratL. 1aek
of a rigid socal sEtructure, absence of territoriality, eLt. Many of Lhese
features can be related to the quality nM distribution ofe their food resrOce
(aqutiec plants), a lw reproductive output, and a low potential for maleI
parencal Investment. However, several aspects of their behavioral ecology ar*
d&etacttlvei Ouftnge form large herde, exhibit sexual damorphima, sad perform
me distinctive mating display. Mansates normally form Imall fluid groups,
are not sexually dlmerphi, and do not exhibit any diLtinctive mating displays.
These, and other differences are d4icuseed in term of morphology. phyesielgy,
habitat preference, amd predation pressure ih the two groups. The feature of
the behavioral ecology of firnIa that make thee vulnerable to extinction are
CATALOGING WEST INDIAN MANATEES IN FLORIDA. G.I. Rathbun and J.P. Reid. U. S.
Fish and Wildlife Service, Denver Wildlife research Center, Gainesville,
Florida. USA 32609.
Since 19*2. photographs of distinctively scarred manatees (Trichechue emutus)
Ln Florida have been compiled annually in a state-wide manatee identafcat&on
catalog, which now totals 746 individels. Aesightings of known individuals at
winter aggregation iates (mostly warm water discharges and natural spring$) have
provided Information on the movements and site fidelity of uanate*e in Florida.
Sit* fidelity has been documented for 80 individuals, including nine anmils
known to have ueed the same site on four or more years. Thirteen manatees.
however, chnad vinater aggregation *alt** between winter season and chree
changed within a single seeson. A total of 36 manatees have been resa ged at
different agregatio1n mites with the greateet movemenLa, both in number and
distance* occurtring n the east ceast. Three indlivduals are known to have
traveled nearly 600 kb between Jacksonville and Fort Everglades, indicating hate
10ft distance movements are nIt uncommon. Seasonal movements from outh to
north have been documented for nine manatess. The catalog has demonstrated thst
anatees can move frequently and great distances, which has important
mtplicatione in developing effective conservation strategee.
RADIOTAC ATTACH ENTS FOR SIRENIA. J.P. Reld, G.. kathbun, and J. Boura.a.,
U.S. Frih and Wildlife Service. Denver MWldlfe Research Center, Gaineeville,
Florida, USA 32604.
A major obetacle in studying the movements and life history of Sirania that
Occupy saltwater habitats has been a safe method of attaching radio-frequency
transitters that would overcome the problem of saltwater attenuatlon. After
nearly five years of cautious development, we have achieved such an actachment
for konatees and designed a prototype for dugongs. The assembly is composed of
a peduncle belt with a quick-fit buckle, a two meter long nylon-rod tsther, and
a floating polypropylene cylinder housing a L64 megahertz transmitter. This
arrangement has been successfully used to radio-track manatees (Trichechus
manatus) in altwater habitats in Florlda vith no ill effect to the animals.
MANAGING AND CONSERVING SIRENIAN POPULATIONS SUBJECT TO TRADITIONAL
IPLOITATION. 4. Sa th, Sir George Fleher Centre, James Cook
university Qld. Australia; B.E.T. Hudson, Dept. Biol. Sct., JCU;
J. A. P9well, Uni. of Washington, Seattle, USA.
All extent Sirenians Ire under severe threat.
complex issues such as: 'traditional rights': their being no
guarantee that Sirenian population decline can be reversed;
conflicts with other users: make sustained management difficult.
Sirenians are long-lived, slow reproducing animals that are totally
unsuited to commercial exploitation. Rapid change in hunting
technology and increase in human populations have precluded the
formation of self-regulatory laws being made by users; management
agencies are often unused to dealing with traditional cultures;
forces for exploitative development often outveight sustained
ianagesent agencies may decide to let problems resolve themselves;
all Sirenian killing can be banned; co-operative management can be
undertaken. Case studies from Papus Now Cuinea, Australia, Africa
and America are discussed. A better understanding of the needs of
Sirenians and the human cultures that impinge on then is required
to formulate and implement sustained management of Sireniana and
for the societies which exploit thaee.
THE MANATEE CECUK. R.L. Snips, Insticut fur Anatomic und Zytobiolog e, Justus
Liebig Ualverstrla, AtulVe 123. 6300 Glessen, east Germany.
The large intestine of the WMest Indian uanatee, Tlrchechus manatus, endemic to
the oast0al freshuatera of Florida, most probably represents not only & vast
fermetatlon vat but alo a meeost econoai organ for conservation of water. The
ecua is in relation to the enormous length and circumference of the colon
Relatively small. Its for is reminiscent of the ceca in many avian forms,
namely, it possesses two born. The ileum enters the cecal corpus from which the
horns project. The corpus open into Lbs ampulla cecl via a wide communicaclio
with indications On the bordering valls at folds possibly for directing flow of
4diests. The eacrance into the colon proper is at the base of the ampulla. The
entire internal Muco s of the cecum is lined by stvacified keratiniting quaiuau
*plthelium, an unusual feature in ceca and apparently in unique sranian
ULTRASThUCTURAL PROPERTIES OF THE EPIDERMIS IN THE MANTEE (TJlCHJECHUW
ThICHECHUS) AND THE DBOTTL-NOSED DOLPHIN (TURSIOPS TRLUNCATUS) AS ADAPTATIONS TO
VARIED SALINITY. V.E. Sokolov and L.V. Stepanova, Institute of Evolutionary
Animal Morphology and Ecology, CSSA Acddemy of Sciences, Moscow 117071 USSR.
The skin of marine aalets has undergone considerable adaptation to aquatic life.
The epidermis of Tinjchcua trichechus, which lives in the littoral zone and is
exposed to a wide ranfte of salinity, and Tursiops truncatus, which lives in the
open sea. La relatively constant salinity, both have a thick stratus corneum with
many Odlad granules. The latter are the sources of the lipid material of the
intercellular cement of stratut corneum. Epidermal corneacytes of the manage
have, in addition, a crosaa-lnked envelope that functions as an oanotic membrane
and permits the animals to sustain oastic stresses and thus occupy a range of
salinity that includes freshlater. Dolphin epidermal cells are not fully
keratinized and the creas-ILnked envelope is absent, which explains why
iraversible changes occ w in them after long exposuI to freshwater (Harrison
and Tarley. 1974).
DUGONG (DCONG DUGON) IN HEW-CALEDONIA. J.P. fylvestra, S.E.C.T.T.
4, allee de la forget, 92360 Meudon a ort. France and B. Richer ve Forgs.
Orstom, I.P. AS, Noumea-Cedex, Nouvelle-Caledofie,
Information concerning the population of augong in New-Caledonia is fragmentary'.
These animals are relatively abundant in the New-Caledonia lagoon but they are
difficult to approach and to observe. They are protected and cmeti.mes, the
tribes have per=Lta to catch few Individuals in the occasion of a ftatival, Fron
the account-book of the Gendarmerie Nationale of 16 dugongs caught during these
Occasions between 1975 and 19654, 7 were males, 8 were females and another,
unlawfully caught, was of unknown sex; 9 of them were harpooned and the other 7
were caught by nees. The lengths of chose dugongs were between 1.2 and 2.9 n.
The majority of them were solitary, however one male was accompanied by a female
and a juvenile, and a female was 4acoapanied by another individual of
undetermined sex, Among the females, milk was present in the udder of one
individual (Caught in April or May 1983). The first months of the year would
probably be the breeding season for that population.
WATER MOVISNT PATTRIIS AID POPULATION STRUCTURE Or THI WEST INDIAN
MANATEE, TRICHECHUS manatus, IN BOIOSASSA SPRINGS, FLO3RIDA. Nina N. Thumwar and
lahn G. rria. Florida Institute of Technology.
Observarions wre made the winters of 1904 and 1985 on the manfies which
congregated in the Blue Water Rua (ABR), headvacers of the Homosessa River.
Manatee were identified by their scar patterns ustaing aerial and underwater
photographs. In addition to photographic records, che sex, approximate length,
behavior, cla of day, and air and water temperatures were recorded for each
encouncer with a manatee. Sixcy-two animals were identified over Cth course of
cha study, indicating that che MBM i used by aore manacae than previously
thought. Mana eas were also found to have a dltcinct preference for a specific
area within the BSK, but the area preferred differed between the two years. It
appears that he current slow ep*ed zone should be extended farther down the
river. No manacess were found to reside within the BWR for the entire winter;
however, the considerable variatton in h percentage of cime individual manateea
were sighted within the run can be used to aettate the relative home ranges.
Of the sixty-Cwo animals identified at BWR, 40Z had been sighted in Crystal
River by the U.S. Fish and Wildlife Service and 29Z were recorded in both
refugia during a single water.
AGE DETERMINATION IN THE WEST INDIA.N HMAATEE BASED ON THORACIC FLIPPER
RADIOGRAPHS. Alascair C. Watson, Nancv K. He sen. College ot Vetarinary Medlcine,
University of Florida, Gatnesvilll, FL USA 32610
Plain file radiography was used to analyze the developmental sequence of bones in
the thoracic flipper, as a technique for age determination in salvaged carcases
from a Florida population of Wear Indian manatees, Trichechus manaeus.
tadlographs of the acapula, humerus, radius and ulne, carpus and manus were
examined from 125 manactes ranging in tcoal length from 103 ca newborns to 355 cs
adults. Individuals wvre assigned to particular developmental stages based upon
the radiographic indications of osaficatlon events initial appearance or
fusion. Newborns had 22 ossification centers: dlsphyses of scapula, humerus,
radius, ulna, 5 aesccarpals and 13 phalanges (phalangeal formula 220.127.116.11.2).
The remaining developmental stages were defined by a sequence of appearance of 40
epiphyseel oseification centers and their subsequent fusion co cheir respective
d1aphyses. In addition 8 ossification centers were detected in the carpus and
resulted In 6 carpel bones (2 rove of 3 each); there being 2 or 3 separace
centers contributing to the distomedlal ('cara 1+2") carpel bone of the adult.
All metacarpals and most phalanges had separate proximal and distal epiphyseal
ssificaticlon centers. The chronology of these events may be established by
comparng these data with radiographs frost known-age, known-length manatees.
Supported by USFWS PO" 83981205.
RESEARCH PROGRAM IN INFORWPTION PROCESSING AND SOCIAL. BEHAVIOR IN CAPTIVE WEST
INDIAJN MANATEES. HD. Woj-.ard Department of Psychology, University of Windsor,
Windsor, Ontario, Canada %98 3P4.
Information processing in best lnd:an Manatees (Trihechus Manatus7 was investi-
gated in series of discrimination problem experiments involving captive manatees
at 4arineland near St. Augustine, Florida and at Miami Seaquarium. With controls
to rule out echolocation, odor taste cues, and other alternative explanations it
has been demonstrated that manatees can visually discriminate underwater targets
on the basis of differences in brigntness, size, shape, aorizontal/vertical move-
sent, colour, and horizontal/vertc:al orientation of stripes. Although most of
the prior speculation in the literature suggested poor vision in manatees these
results indicate an ability to mase use of a variety of visual information. These
findings are consistent with results from some recent anatomical research on
manatee eyes. The lack of clear evidence for cones make the successful colour
discrimination particularly interesting. Ability to solve relatively complex
problems was demonstrated by successful development of learning sets on size
reversal discrimination problems an. by success with a variety of visual matching
to sample problems. Long term recall! was demonstrated on visual siLe Jiscri mn-
ations involving durations up to ." months. Place learning experiments results
indicated some manatee! relied on left-right discrimination while others learned
to locate a place. Observations :-, social behaviour in the same settings suggest
some hypotheses about nursing, sex-al and agonistic behaviours and individual
differences that aight be useful :.. guiding research on free roaming manatees.
Anonymous. 1985. The permit system for traditional hunting of
dugong: Hope Vale. Reeflections (Great Barrier Reef MArine
Park Authority, Townsville, Qld., Australia) Free Issue No.
Anderson, P.K. 1984. Migration, dietary quality, and winter
movements in a subtropical dugong population. Bull. Ecol.
Soc. Amer. 65(2): 158.
k-Knderson, P.K. 1984. Observations on the behavior and ecology of
dugongs on the coast of Queensland. Nat. Geogr. Soc. Res.
Repts. 16: 37-42.
>Anderson, P.K., and R.I.T. Prince. 1985. Predation on dugongs:
attacks by killer whales. J. Mammalogy 66(3): 554-556.
Baldwin, C. 1985. Management of dugong: an endangered marine
species of traditional significance. The need for user
involvement in an integrated program of research,
management, and education. Great Barrier Reef Marine Park
Authority (Townsville, Qld., Australia) Technical Report
Begley, S., J. Carey, and J. Callcott. 1983. Death of the Persian
Gulf. Newsweek 102(4): 79. July 25, 1983. [Brief account of
dugong mortality caused by the Nowruz oil spill.]
Best, R.C. 1984. The aquatic mammals and reptiles of the Amazon.
In: H. Sioli (ed.), The Amazon. Limnology and Landscape
Ecology of a Mighty Tropical River and its Basin. Dordrecht,
Dr. W. Junk: 371-412.
Buergelt, C.D., R.K. Bonde, C.A. Beck, and T,J. O'Shea. 1984.
Pathologic findings in manatees in Florida. J. Amer. Vet.
Med. Assoc. 185(11): 1331-1334.
Eisentraut, M. 1984. Das Gaumenfaltenmuster bei Schliefern,
Elefanten und Sirenen. Bonn. Zool. Beitr. 35(1-3): 29-37.
[In German; English summary.1
Etheridge, K., G.B. Rathbun, J.A. Powell, and H.I. Kochman. 1985.
Consumption of aquatic plants by the West Indian manatee. J.
Aquat. Plant Manage. 23: 21-25.
Galantsev, V.P., and L.M. Mukhametov. 1985. Functional-structural
adaptations of the cardiovascular system in the manatee
\ TriQhhgbus mZnaLua. Jour. of Evolutionary Biochem. and
Physiol. (Consultants Bureau, Jan. 1985): 201-205.
[Translation of Russian article in Zh. Evol. Biokh. Fiziol.
20(3): 288-293, 1984.1
Gallo R., J.P. 1983. Notas sobre la distribucidn del manati
(Trli.hchbu maaatua) en las costas de Quintana Roo. An.
Inst. Biol. Univ. Nac. Aut6n. Mdxico 53(1); 443-448.
Inuzuka, N. 1984. [Restoration of EsStyi.U~.] Tokyo, Kaimeisha:
1-146. [In Japanese.]
Inuzuka, N. 1984. Skeletal restoration of the desmostylians:
herpetiform mammals. Mem. Fac. Sci. Kyoto Univ., Ser. Biol.
Kendall, B. 1985. Sea cows. Swara (Magazine of the East African
Wildlife Society) 8(1): 32-33.
Kinnaird, M.F. 1985. Aerial census of manatees in northeastern
Florida. Biol. Conserv. 32(1): 59-79.
Lewis, R.R., III, J.M. Carlton, and R. Lombardo. 1984. Algal
consumption by the manatee (Tri~h~buz naaAua L.) in Tampa
Bay, Florida. Florida Sci. 47(3): 189-191.
Lomolino, M.V., and K.C. Ewel. 1984. Digestive efficiencies of
the West Indian manatee (Trichauba manatug). Florida Sci.
Marsh, H. 1985. Results of the aerial survey for dugongs
conducted in the Cape Bedford to Cape Melville area in
November 1984. Report to the Great Barrier Reef Marine Park
Authority (Townsville, Qld., Australia), April 1985: 1-67.
Packard, J.M. 1984. Impact of manatees Eijchichu nat.Ug on
seagrass communities in eastern Florida. Acta Zool. Fennica
Packard, J.M., Summers, R.C., and Barnes, L.B. 1985. Variation of
visibility bias during aerial surveys of manatees. J. Wildl.
Manage. 49(2): 347-351.
Rainey, W.E., J.M. Lowenstein, V.M. Sarich, and D.M. Magor. 1984.
Sirenian molecular systematics including the extinct
Steller's sea cow (lydZodA.mlia SiASa). Naturwiss. 71(11):
Reynolds, J.E., III, and J.C. Ferguson. 1984. Implications of the
presence of manatees (T.Jichhhua mAnatul) near the Dry
Tortugas Islands. Florida Sci. 47(3): 187-189.
Said, R.J. 1985. Sea cow stories. Swara (Magazine of the East
African Wildlife Society) 8(1): 34. [Two traditional stories
of the origin of sea cows, from the Digo and Giriama of
coastal Kenya, respectively.]
Shane, S.H. 1984. Manatee use of power plant effluents in Brevard
County, Florida. Florida Sci. 47(3): 180-187.
Walters, M.J. 1985. Marvelous, magnificent manatees. Reader's
Digest 127(760): 171-172, 175-176. August 1985.
Welsby, T. 1967. The collected works of Thomas Welsby (A.K.
Thomson, ed.). Brisbane, Jacaranda Press: 2 vols. [Vol. 1,
pp. 102-110, and Vol. 2, pp. 233-257, contain very detailed
accounts of dugong habits and hunting in Moreton Bay,
[EDITOR'S NOTE: Beginning with this issue I will be
including in the "Recent Literature" department citations dealing
with the Order Desmostylia, extinct herbivorous marine mammals of
the North Pacific region. Once considered sirenians and now
viewed as near relations of the latter, they have enough history,
ancestry, and ecology in common with sirenians to merit an
honorary place in these pages.]
CHANGES OF ADDRESS
Lic. Alberto R. Estrada, Apartado Postal 5152, La Habana 5, Cuba
Dr. R. E. Johannes, CSIRO Marine Laboratories, GPO Box 1538,
Hobart, Tasmania 7001, Australia
Dr. Alastair G. Watson, Orthopaedic Research Laboratory, Shriners
Hospital for Crippled Children, MDC-64, 12901 North 30th
St., Tampa, Florida 33612 USA
I[Sir.nwa thanks Helene Marsh for its new dugong logo, which
will alternate with our manatee in future issues.]
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