NUMBER 37 APRIL 2002
IN
THIS ISSUE: - REHABILITATED CALVES RELEASED IN
AND
-
DUGONG STUDIES IN THE
(pp.
11, 12)
-
ABSTRACTS FROM
MANATEE POPULATION ECOLOGY AND
MANAGEMENT
WORKSHOP HELD IN
The Manatee Population
Ecology and Management Workshop was held in
Ø To review progress in manatee population research, and demonstrate the value of current approaches.
Ø To improve data analyses and population models for future population assessments, e.g., the planned status reviews by the U.S. Fish and Wildlife Service (FWS) and Florida Fish and Wildlife Conservation Commission (FWCC) in 2003.
Ø To promote peer review of current population research by a panel of wildlife population experts outside of the manatee research community.
Ø To make recommendations and promote collaborations for future population research.
Ø To synthesize current results in a technical report that will be made available to the public, scientific community, managers, and policy-makers.
Ø To achieve a balanced approach to manatee conservation.
New data analyses were
presented at the workshop, and a group of 8 scientists with expertise in
wildlife population assessment (Solange Brault, Daniel Goodman, Aleta Hohn,
Fred Johnson, Gil McRae, Helene Marsh, Jim Nichols, Ken Pollock) reviewed the
current techniques used to assess manatee population status.
Approximately 100 people
participated in the 2002 workshop. The
last time biologists convened a formal meeting to review and discuss manatee
population biology was in 1992. That
meeting did not include managers, while the attendance at the 2002 workshop was
a mixture of research and management biologists, and representatives from
boating and conservation groups. A few
reporters also attended.
The workshop sponsors
were: The U.S. Geological Survey (USGS),
U.S. Fish and Wildlife Service, Marine Mammal Commission, Florida Fish and
Wildlife Conservation Commission, Ocean Conservancy, Florida Power & Light
Co., Pegasus Foundation, Mote Marine Laboratory, and Wildlife Trust.
John Reynolds gave the first
of 14 presentations, briefly reviewing the history of manatee population
research and its application to manatee recovery efforts. He emphasized that we have more and better
quality data on manatees than on any other marine mammal. He also pointed out that long-term manatee
data sets, some of which date back to the late 1960’s, increase in value over
time. The quantitative population criteria that appear in the third revision of
the Florida Manatee Recovery Plan were based on analyses of long-term life
history data, published in the proceedings that resulted from the 1992
Technical Workshop on Manatee Population Biology (Population Biology of the
Five management and 8
research presentations followed. Among other research findings, biologists
reported new information on the age structure of dead manatees, adult survival
rates, reproductive rates, and use of models to determine population growth
rates. Although the workshop did not
attempt to incorporate habitat and carrying capacity issues, the need to
integrate population and habitat data was voiced by both researchers and
managers. Some of the highlights were the following.
Meghan Pitchford (FWCC)
reported finding that of the female manatee carcasses that have been aged, 73%
did not live long enough to produce more than one calf, and only 20% lived long
enough to produce more than 2 calves.
Excluding the 0-1 year age class, the average age of recovered carcasses
is 7.7 yr. Only 1% of the manatees aged (n=2026) were 30 or more years old. She also found that one can “read between the
lines” that form growth-layer-groups in manatee ear bones, i.e., changes in
growth rate (determined from growth-layer measurements) may indicate the onset
of sexual maturity.
`However, the above findings
based on carcass data differ from those based on photo-id data. Resightings of living adult females,
particularly at Crystal River in the Northwest region and Blue Spring in the
Upper St. Johns region, indicate that many individuals live well beyond 20
years, and several of those who were first documented over 30 years ago
continue to be resighted. Most of these
females also produce calves every 2-3 years.
Several reviewers recommended comparison and integration of the carcass
recovery and photo-id data in order to better our understanding of the manatee
population’s age structure.
Bill Kendall and Cathy
Langtimm (USGS) presented new estimates of manatee reproduction and survival
based on resightings of live manatees, which were incorporated into a
stage-based model presented by Mike Runge, also with the USGS. The Runge et al. estimated population growth
rates for the Northwest,
The reviewers were unanimous
in their rejection of the synoptic survey data as a means to determine
population trend. However, several
managers felt that having some idea of the minimum population size was
useful. Use of aerial surveys to
determine manatee distribution and habitat was strongly supported by both
researchers and managers.
Cathy Langtimm, Ken Pollock,
Jim Nichols, Fred Johnson, and others recommended that future studies be
designed to better understand causal relationships between management actions
and population response, rather than simply being retrospective. Examples would be development of an adaptive
management model to evaluate the potential impacts of changes in warm water
availability on manatees, and determining efficacy of management actions to
reduce deaths caused by manatee/watercraft collision.
Dan Goodman emphasized that
managers will need to trust complex models that integrate information from
different data sets in order to make sound decisions. The influence of habitat quality and
nutrition on reproductive rates must also be incorporated.
Solange Brault and Aleta
Hohn expressed concern about the lack of information on manatee reproduction in
the Southwest region. They cautioned
against extrapolating parameter estimates from other regions to the Southwest,
and suggested that genetic markers and other tools need to be further developed
to understand potential differences among regional groups.
The reviewers and many other
participants believed that Population Viability Analysis (PVA) would be the
best way to integrate available data sets and estimates to develop a
forward-looking projection of manatee status.
The impact of growth of
The
strongest recommendation to come out of the workshop that is important to
manatee status re-evaluation is that status needs to be projected forward in
time. Any status re-evaluation must, therefore, also include assessment of
potential changes in manatee habitat, particularly in light of human population
growth and coastal development.
The reviewers unanimously
called for better communication among managers, researchers, and other
stakeholders concerned with manatee recovery issues. This workshop was a huge step in the right
direction, but renewed commitments to improve communication must be acted upon
immediately to keep the momentum going.
The FWS plans to follow up
quickly with a smaller meeting to specifically address negligible impact under
the Marine Mammal Protection Act, as their draft rule for manatees is due by
MARINE MAMMAL CONFERENCE IN MEXICO
La Sociedad
Mexicana de Mastozoología Marina, A.C.
Anuncia/Announce the
XXVII Reunión Internacional para el Estudio de los Mamíferos Marinos
XXVII International Annual Meeting for the Study of Marine Mammals
Mayo 12-15, 2002/May 12-15, 2002
Hotel Villa del Mar/ Villa
del Mar Hotel and Acuario de Veracruz/Veracruz Aquarium
City of Veracruz, Veracruz, México.
Información más detallada en la página de internet de la SOMEMMA
More information at the web page of the SOMEMMA, <http://somemma.ens.uabc.mx>
También puedes contactar al Comité Organizador de la XXVII reunión
Or contact the Conference Committee:
Presidente Académico: Dr. Luis Medrano G., <lmg@hp.fciencias.unam.mx>
Presidenta Ejecutiva: Biol. Blanca Cortina, <corblan@hotmail.com>
CALL FOR PROPOSALS
Sirenian
International is a grassroots organization dedicated to worldwide manatee and
dugong conservation through research and education. We are interested in sponsoring research,
conservation, and education projects involving manatees and/or dugongs around
the world, with priority given to projects in developing nations where funding
is traditionally difficult to secure. We
funded one project (on dugongs in
There is no
deadline for application; proposals are accepted year-round. HOWEVER, grants are awarded subject to review
by our Scientific Advisory Council and the availability of funds. Please send a preliminary email to Sirenian
International Grant Proposals (c/o <
In keeping with our mission of sirenian conservation through inter-cultural collaboration, we encourage networking, community outreach, and student development components in all proposals. We will use the following criteria to evaluate grant proposals:
Sirenian International believes that the benefits of projects meeting the above criteria reach far beyond research and academia, to facilitate sharing of knowledge with local communities, students, governmental agencies, non-governmental agencies, and other conservation groups. Although our focus is on manatees and dugongs, SI hopes that our grant applicants will better understand the complexity of conservation issues, and the compelling need for partnerships among all parties involved, in both developing and industrialized nations.
Each grant recipient agrees to register with Sirenian International as a Participating Member and to submit information about their project to SI for use on our website and in our newsletter. To apply for a small grant, please submit the following:
· relevance of study and appropriate background information, including a literature review;
· clearly stated objectives and how the anticipated results of the project relate to the stated goals of any appropriate manatee or dugong conservation efforts within your host country or at the regional level if your host country has no conservation program;
· clearly stated methods, estimated duration of the project, and plans for follow-up, application of results, and/or future work;
IMPORTANT: Electronic submissions are preferred. DO combine the cover letter, proposal, CV,
budget, etc., in ONE file and send as attachment to e-mail [MSWord document
(.doc) or Rich Text Format (.rtf)]. DO
NOT use fancy formatting; DO NOT include images or photos in the document; DO
have your reference letters sent in the same manner. Submit to <
THE
EMILY B. SHANE AWARD
The Emily B. Shane Award supports
conservation-oriented, non-harmful field research on free-ranging odontocetes
and sirenians. ("Non-harmful research" is that which poses a minimal
risk to the health and life of an individual animal and to other species within
the ecosystem. Research that entails
capture or invasive techniques is acceptable only if carried out by competent,
experienced personnel and provides clear benefits in terms of conservation and
scientific knowledge. Applicant must
document previous experience and outcomes.)
The award honors Emily B. Shane (1924-1995), a fine amateur
naturalist and dedicated conservationist.
Funds are awarded to projects with clear conservation priorities for an
odontocete or sirenian species, population, or habitat critical to the
species. Research that also impacts a
local human community in terms of increased public awareness, capacity
building, or education may be given special consideration. The award, given annually, will total
approximately US$10,000. The award
committee may opt to divide the award
among two or more applicants. Although
awards will be made for no more than one year at a time, applicants may apply
more than once for the same project.
Applications are due by
Evaluation Criteria: The application
must include the following materials:
·
A proposal, not exceeding
three pages in length (Times font, 12 point type, single space, 2 cm
margins). Briefly outline the proposed
research, objectives of the study, methods, role of the proposed work in
conservation, the time period for the research, person(s) conducting the field
research and role of each, and literature cited.
·
A budget, including
other funding applied for, or already held, for the proposed research. Applicants with reasonable budgets who
demonstrate the greatest financial need will be given special attention. Funding
requests should be for direct field research expenses only.
·
A current C.V./resume
of the applicant, up to three pages in length.
·
Three references with
e-mail address, phone number, and relationship to applicant.
Eligibility: The award is
available to students and other researchers who meet the evaluation
criteria. The application should be
submitted by the person conducting the research. A student’s professor should send a cover
letter of support, if his/her involvement in the project is essential to the
completion of the project. Applicants
must have obtained any necessary permits or authorizations for conducting the
proposed research before the award funds are disbursed.
LOCAL NEWS
Hand-Raised Dugong Calf
Rehabilitated and Released. - On
The
Detachment of the tracking
device thwarts our intention to monitor the dugong's progress, but should not
significantly alter his survivability (unless he does something completely
inappropriate like head out into the
A New Baby Amazonian Manatee. – The
team of the Aquatic Mammal Lab of INPA,
The pregnancy was confirmed visually about 10 weeks prior to the birth
when it was observed that the vulva was swollen and extended. An ultrasound
examination was performed on 19 January, to confirm the pregnancy and to try to
estimate the size of the fetus. From late January until 3 weeks after the
birth, Tukano and her calf's behavior were monitored by underwater TV and
recorded on videotape. On 21 February, after
Milk collection, diving frequency, behavior and vocalization are being
recorded. - Vera
M. F. da Silva
Amazonian Manatee
Rehabili-tated and Released. - On
Airuwe was examined by
Marcia Picanco, a Brazilian veterinarian, before release and found to be in
good health. He was fitted with a belt-mounted transmitter donated by the
Instituto Mamirauá (
We would like to thank all
the people who have helped us with the difficult but satisfying task of
bringing up and reintroducing an Amazonian manatee, in particular veterinarians
Greg Bossart and Marcia Picanco, Miriam Marmontel of the Instituto Mamirauá,
Jim Reid and Bob Bonde of the Sirenia Project, Salud Colpatria, the Columbus
Zoo, Save the Manatee Club, Corpoamazonia (Leticia), Fauna and Flora
International, the British Embassy Bogotá, Jim Valade, Antonio Mignucci, Ruby
Montoya, Timothy Ross, Elizabeth Kendall, and numerous fishermen in the Puerto
Nariño area. - (Source: SIRENIAN Listserv)
New Antillean Manatee
Exhibit in
The four apparently arrived
in good shape. I haven't been there yet but in the TV feature their aquarium
within the new South America Complex appears very spacious and attractive both
for animals and visitors. The Zoo hopes the animals will breed. The Zoo of
Nuernberg, where Henriette came from, claims that they raised 14 manatees and
are the most successful zoo at breeding Antillean manatees in captivity.
Two Web pages, <http://www. dr.dk/fyn/manatus/>
and <http://www.
odensezoo.dk/aktuelt/aktuelt.htm>, give more details in Danish, of which
I speak zero - now at least I know that søko means seacow and søkøer is the
plural. - Gisela
& Hans Rothauscher <http://rothauscher.bei.t-online.de/
>
To
Downlist or Not to Downlist? - On
In the
end, FWS still did not completely accept the recommendations of its own experts
on the Manatee Population Status Working Group (MPSWG). The most important
remaining differences in the critical numbers adopted were: average annual
adult survival rate of at least 90% (as opposed to at least 94%, with
statistical confidence that it is not less than 90%); and average annual rate
of population growth of zero or greater (as opposed to at least 4%, with
statistical confidence that it is not less than zero). (A 95% confidence level
applies throughout both the MPSWG and FWS versions.) Although the final numbers
were an improvement over the earlier drafts, nonetheless the inescapable
conclusion is that FWS has lowered the bar to downlisting. Whereas the two
smallest Florida subpopulations (Northwest and Upper St. Johns River) already
meet either set of criteria, the much larger Atlantic Coast subpopulation meets
only the less stringent FWS criteria for potential downlisting (data from the
Southwest area are incomplete).
In 2001, at
least 325 manatees died from various natural and human-related causes; at least
81 of these deaths were caused by watercraft. Both total deaths and
watercraft-caused deaths increased from the year before. Since these figures
represent only known manatee deaths, the actual numbers of both total deaths
and watercraft-caused mortalities are likely considerably greater. Even using
these figures, however, the total number of manatee deaths is 10% of the 3,276
manatees counted during the winter synoptic aerial surveys conducted in January
2001 -- which was the highest number of manatees ever recorded in such a survey.
The
situation thus far this year is even more bleak. According to the Florida
Marine Research Institute, as of
Thus, the
manatee is currently confronting precisely the situation which the FWS has
declared (in its Biological Opinion on the CSLNG Development Project,
Stomach Contents of Dugongs
from
Dugong Mitochondrial Genome Sequences Obtained. - Modern molecular techniques are currently being used
to answer some interesting questions about dugong evolution and population
structure. The complete mitochondrial genomes from two dugongs have recently
been sequenced, one by a group of researchers at Massey University, New Zealand
and the other by the Lund University research group in Sweden. These sequences
will be used to help resolve ancestral relationships amongst mammals.
Mitochondria are the
powerhouses of cells. Their main functon is respiration and they exist in many
copies per cell. Vertebrate mitochondrial (mt) DNA is about 17,000 base pairs
in length, and codes for 20 transfer RNAs and 13 proteins that are involved in
processes common to all living things. Complete mt genomes have proven to be
useful for phylogeny reconstruction, particularly for mammalian evolution.
Latest results in this field are showing a high congruence between trees
constructed using mt data and those from nuclear markers. One of the problems
with earlier trees was that the branch leading to the elephant was very long,
and this can mislead tree reconstruction methods (this is the problem of “
Mitochondrial DNA also contains a small, extremely
variable region known as the D-loop/control region. This region is useful for
addressing ecological questions about existing dugong populations. An initial
analysis of this region in the two recently sequenced dugongs, by researchers
from
Dugongs at Hinatuan, Surigao
del Sur,
When I first arrived I was
told of the presence of dugongs and up to 5 species of endangered turtles in
the area, and was given pictures to prove it -- quite a surprise, as I found
out afterwards when I reported it to the National Government; they were unaware
that the population existed!
Modern records support the
presence of dugongs (Dugong dugon) in
Hinatuan as far back as 1950, but they most likely inhabited the area even
before this date. Over the past several decades, dugong numbers have
slowly decreased due to (1) illegal fishing techniques such as
dynamite and cyanide fishing; (2) the extensive uncontrolled use of fish
corrals and illegal mesh size fishing in protected areas; and (3) illegal
over-expansion of fish ponds.
For decades, the DENR
(Department for Environment and Natural Resources) assumed the
population was extinct in Surigao. As a result, no new endeavors were
initiated to protect or preserve this endangered species in the Surigao del Sur
region. My initial research indicates that, in the Surigao region, dugongs can
only be found in Hinatuan. They appear to be extinct in the
surrounding areas of Surigao del Sur, with unconfirmed recent reports at
In April 2001, a baby dugong
was killed in a fish corral, and after interviewing local people, I found
that two other baby dugongs had been killed in the last 6 months. I
contacted national governmental agencies and the World Wide Fund for
Nature (WWF), who acknowledged that they were unaware of the presence of
dugongs in the Hinatuan area, and stated that they had terminated recent
surveys 200 km south of there, thus missing the whole area.
From October 2000 to October
2001, five baby dugongs were killed, and one tagged and released by
fishermen, all in Hinatuan municipal waters. This is strong evidence
that either the population did not go extinct, or that the area has been
re-populated in recent years. But, with five infants killed in
the past year, and increasing fishing intensity, is there hope for
continued recovery? At present the outlook is bleak. The
dugong's plight here is very serious and will require equipment, funding,
support and enforcement. I am publicizing these data to raise the profile of
dugongs in the
There is massive opportunity
here for scientific research, not to mention Ph.D. possibilities. If anyone has
suggestions I would be delighted to hear from you. - Rowan
Byrne (Centre for Empowerment & Resource Development Inc. (CERD) and Voluntary
Service Overseas, Philippines (VSOP); dugongresearch@yahoo.com)
Dugong Death at
It had fish net markings and
scars all over its dorsal surface (back) that looked like coral cuts, and up to
6 slashes behind its head and upper dorsal region that appeared not to be from
netting; they could be described as man-made. These slashes were 1 to 2 inches
deep, cutting deep into flesh, and blood flow could be seen 3-4 inches behind
the left eye. In one of the photos there appear to be remains of blood flow
from the right nostril. It appears that the dugong was caught in a net, and as
the net was being pulled in the dugong was found alive, so the net owners tried
unsuccessfully to kill the animal with some sort of knife or machete, and the
dugong somehow managed to get free and swim for safety. It began to approach or
return to the area inshore that may serve as a safe haven for dugongs in
Hinatuan Bay, and somehow it may have been disturbed and began to return to the
open sea when it entered a fish corral and later died from the incisions and
cuts it received. The dugong also appeared severely bloated, so there is a
possibility of poisoning, maybe due to dynamite or cyanide fishing. -
Compiled by Rowan Byrne;
field details taken by Gary Cacho.
Observations of the Dugong
in
The study area consisted of
a number of small sheltered bays within the Con Dao archipelago, located
approximately 85 km southeast of mainland
Dugongs were observed during
November 2001–January 2002 from a number of elevated hillside vantage
points. Observations were made with
unaided and aided sight, using 10x50 binoculars mounted on a tripod for
long-range observations. On spotting
dugongs at the water surface, notes were taken on the period of time the animal
spent at the surface, the time spent submerged between successive surfacings,
and also on the behavior of the dugong at the surface including the number of
breaths taken. If the dugong was in
shallow water, notes were also made on behavior under the water surface Free-ranging dugongs were observed on 13
separate days in November 2001, 7 days in December 2001 and 9 days in January
2002, out of a total of 37 days spent observing. Transect surveys were conducted at two sites
in order to assess seagrass species composition and density of dugong feeding
trails.
Thirty-three free-ranging
dugongs were observed between November 2001 and January 2002. Dugongs were seen during morning and
afternoon observation periods and at both high and low tide. Dugongs were observed feeding in seagrass
beds ranging from 3-10m in depth. On
several occasions, mothers and calves were seen together and in each case the
behavior of the juvenile dugong was observed rather than the adult. On one occasion 3 dugongs were seen together.
Insufficient data were
recorded to enable comparison between sub-mergence times of dugongs feeding in
deep water (up to 12m) and submergence times in shallower water (1-4m),
although there may be other factors involved, such as seagrass cover. However, there appears to be an effect of
tides on submergence times, with dugongs appearing to surface more frequently
at low tide than at high tide.
The mean submergence time of
4.2 minutes compares favorably with observations recorded in Indonesia by De
Iongh et al. (1997) of 4.6 minutes, surveys that were also done in deeper water
up to 9m depth, compared to observations made in shallow water up to 3m in
Australia by Anderson and Birtles (1978) who recorded an average submergence
time of 1.2 minutes. This supports the
suggestion by De Iongh et al. that submergence time correlates with the depth
of the seagrass bed.
Recommendations
for further research:
1. Long-term study of the
dugong population in Con Dao in association with seasonal changes in seagrass
composition and abundance. Construct
portable viewing platforms for erection in subtidal seagrass beds in Lo Voi and
on Lo Voi Cape. This would be an ideal
study for a Vietnamese Masters or Ph.D. student with support from an
institution such as the NTIO.
2. Research into the
possibility of stabilizing slopes adjacent to Con Dao’s roads in an attempt to
reduce soil erosion during heavy rains.
3. Surveys in other known
seagrass habitats in
4. Local community interviews
in other Vietnamese coastal provinces.
5. Collaboration with Cambodian
and perhaps Thai authorities on transboundary dugong conservation initiatives.
References
Anderson, P K., and Birtles, A.
1978. Behaviour and ecology of
the Dugong, Dugong dugon (Sirenia): Observations in
Shoalwater and