NUMBER  37                                                                                                     APRIL 2002

 

 

IN THIS ISSUE:     -  REHABILITATED CALVES RELEASED IN AUSTRALIA

    AND COLOMBIA  (pp. 6, 8)

 

        -   DUGONG STUDIES IN THE PHILIPPINES AND VIETNAM

     (pp. 11, 12)

 

        -   ABSTRACTS FROM VANCOUVER CONFERENCE  (p. 15)

 

 

MANATEE POPULATION ECOLOGY AND MANAGEMENT

WORKSHOP HELD IN FLORIDA

 

The Manatee Population Ecology and Management Workshop was held in Gainesville, Florida, 1-4 April 2002.  The goal of the workshop was to better understand and integrate the roles of research and management in achieving recovery of the Florida manatee.  The specific workshop objectives were:

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 Florida Manatee.  1995.  O’Shea, Ackerman, and Percival, eds.  Copies available from USGS or FWCC).

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, Upper St. Johns River, and Atlantic Coast manatee populations yield results very similar to those obtained by Eberhardt and O’Shea (1995): the Northwest and Upper St. Johns River groups are increasing, while the Atlantic group could be increasing at a somewhat lower rate, or possibly even declining.  Runge modeled the latter group under optimistic and pessimistic scenarios.  In the optimistic scenario, he assumed that adult survival, reproduction, and annual variation in these and other model parameters were moderate, i.e., that they matched the current estimates of survival and reproduction for this region.  In the pessimistic scenario, he used a lower survival rate, moderate reproduction, and higher variability in model parameters.  Runge emphasized that many of the manatee’s life history parameters are still poorly known, particularly for the Atlantic Coast population, and even the best estimates (e.g., of adult survival) have sizeable sampling error.  Given the uncertainties, the take-home message seems to be that although there are hopeful signs of manatee recovery in at least some regions, they aren’t out of the woods yet!

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 Florida's human population (projected to double in the next 30 years) cannot be overlooked in development of a manatee PVA.

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 5 November 2002.  They plan to review manatee status in early 2003.  The FWCC will be reviewing the State’s designation of manatee status even sooner.  Both agencies will undoubtedly draw upon information presented at the April workshop, and may use some of the same scientists to assist them in their review processes.  -  Lynn Lefebvre (Sirenia Project, U.S. Geological Survey, Florida Caribbean Science Center)

 

 

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 Vietnam, by Nick Cox; see report in this issue) in 2001; we expect to fund two projects in 2002; typical awards are US $500 - $1,000. 

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 <caryn@sirenian.org>) to determine current availability of funds and status of the review process, which is semi-annual and roughly correlated with Sirenews publication dates of April and October.

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:

 

  • Involvement of recognized representatives of host countries (e. g. governmental agencies, NGOs, academic institutions, local students) in the planning, implementation and/or evaluation of the proposed project.
  • Inclusion of local people/communities in project design, implementation, data collection, and/or data reduction.
  • Sound project design, meeting the standards of peer review.
  • Demonstrated effectiveness at presenting results to popular and technical audiences.
  • Intent to publish findings at scientific meetings, in peer-reviewed journals and/or through the public media (e.g., popular magazines, newsletters, radio, TV, Internet).
  • Plan for information outreach prior to, during, and/or after the conclusion of the project (e.g. newsletter articles, local presentations).

 

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:

 

  • Cover letter, briefly outlining your request for funds (1-2 pages).
  • A concise proposal (5-10 pages) that includes:

·         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;

  • resume or CV (1-2 pages) for each investigator listed;
  • detailed budget (1-2 pages), including matching funds, if necessary to complete project and whether matching funds are applied for or already secured.
  • Two (min) to three (max) letters of recommendation (1-2 pages), complete with your reference's contact information (e-mail addresses and phone numbers preferred).  If you are a student, one letter should be from your academic advisor; if you are working within an organization, one letter should be from your supervisor or executive director.

 

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 <caryn@sirenian.org>.  For more information, please visit our website at <http://www.sirenian.org> or contact Caryn Self Sullivan (snail mail: 200 Stonewall Drive, Fredericksburg, VA 22401 USA; e-mail: <caryn@sirenian.org>).  All applications will be sent for review to our Scientific Advisory Council (SAC); grants will be awarded by our Board of Directors (BOD) based on recommendations from the SAC and the availability of funds.  Sirenian International, Inc. is a non-profit, tax-exempt 501(c)(3) corporation.

 

 

 

 

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 Monday, 10 June 2002.  Proposals must be submitted via e-mail as .rtf or .pdf files to <EBSA2002@bellsouth.net> and should not exceed 200 KB.  Do not include figures or photographs in the proposal.  Applicants unable to submit an application by e-mail may request permission to send three printed copies; requests must be submitted to the e-mail address above.  Award recipient(s) will be announced by 2 September 2002.

     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

 


AUSTRALIA

 

Hand-Raised Dugong Calf Rehabilitated and Released. - On Tuesday, 12 March 2002, a hand-raised male dugong aged 3 years 3.5 months was returned to the wild in a joint operation by Sea World Enterprises (Gold Coast, Australia) and the Queensland Parks and Wildlife Service (QPWS). This is the same individual that was featured in Sirenews No. 31 (April 1999) and No. 33 (April 2000), who arrived at Sea World on 28 November 1998 at 109.1cm / 19.7kg and upon release was 219.7cm / 197.5kg. To the best of our knowledge he may be the first neonatal dugong to have been hand-raised to independence and the only hand-raised dugong to have been released, although I would welcome being corrected if this is a misconception (in Sirenews No. 33, staff of Toba Aquarium, Japan mentioned "an infant" when describing the rehabilitation and release of accidentally-caught dugongs at Palawan Island, Philippines).

The Queensland dugong, known by those closest to him simply as "the pig", was released into Moreton Bay in southeastern Queensland complete with a peduncle belt, 3m tether and PTT/VHF transmitter, the latter generously loaned to us by Prof. Helene Marsh and Dr. Ivan Lawler of James Cook University, Townsville. Prior to final release the dugong was staged for 4 months in a large, naturally-formed saltwater lagoon on Moreton Island. In this lagoon, which contained abundant seagrass, the pig gained 5kg in weight, grew about 5cm in length, and demonstrated a remarkable capacity to evade people, boats and nets during numerous unsuccessful attempts to recapture him. Unfortunately (for us, but probably not the animal), his entire tracking harness was recovered from the southern end of Moreton Island on Friday, 15 March, 2.75 days after release into the Bay. The harness had broken through the deliberate weak link within the peduncle belt, and the transmitter pod bore numerous unmistakable shark teeth marks.

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 Pacific Ocean). He has two forms of permanent identification - freeze brands on the shoulder region, and two titanium turtle tags in the trailing edge of his fluke - although neither will be obvious to the casual and/or distant observer. Local residents from Moreton Island and dugong researchers from the University of Queensland are keeping an eye out for him, and so far we have received two reports from fishermen of sightings of a solitary dugong of the appropriate size, in the vicinity of where his transmitter was found. We will be revisiting the release area as weather permits to search systematically in that locality.  -  Wendy Blanshard (Sea World Enterprises, P. O. Box 190, Surfers Paradise, Queensland 4217 Australia; tel.: 61-7-5588-2222; fax: 61-7-5588-2266; e-mail: <wendyb@seaworld.com.au>)

 

BRAZIL

 

            A New Baby Amazonian Manatee. – The team of the Aquatic Mammal Lab of INPA, Manaus, are proud to announce the third birth of an Amazonian manatee conceived and born in captivity. This is the second successful birth, this time from a female called Tukano, kept in captivity since 1984. Intense courtship and copulation behavior were observed in February 2001. In April, due to the constant harassment of the males, Tukano was separated and maintained in a different pool with Boo and her two adopted calves (see Sirenews No. 36, 2001). Once the pregnancy was suspected, she was kept alone.

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 2:20 hours of intense labor, a male calf weighing 18 kg and 101 cm long was born. From the rupture of the placenta and the exposition of the tail there was an interval of 1:10 hours before birth. The calf went straight to the surface to breathe; records of the sounds revealed that mother and calf were vocalizing all the time. Differently from the other mother manatee Boo (Sirenews No. 30, 1998), Tukano wasn’t very cooperative in nursing her calf. After 48 hours without letting him feed we decide to intervene. The mother was restrained in shallow water while we raised her flipper, directing the calf to the teat. For 8 days, every hour or every time we noticed the baby wanted to feed, a team of 3 people held the mother and helped the calf nurse. Although the calf wasn’t losing weight, when we had almost given up to start an artificial diet, Tukano finally decided to let her calf nurse, slowing down, waiting for him and stretching her flipper. After two weeks nursing from his mother, the calf gained 2 kg.

Milk collection, diving frequency, behavior and vocalization are being recorded.  -  Vera M. F. da Silva

 

COLOMBIA

 

Amazonian Manatee Rehabili-tated and Released. - On 8 February 2002, Airuwe, an Amazonian manatee aged 3 years 8 months, was returned to the wild by the Omacha Foundation of Leticia and the community of Puerto Nariño. Airuwe was released in the Tarapoto lake system in the Colombian Amazon, close to well-established manatee feeding areas. He was captured in a net near Puerto Nariño in mid-1998 and wounded by fishermen, then transferred to the Omacha Foundation. The Foundation fed, cared for and rehabilitated Airuwe with a view to reintroduction, and he became the focus of a manatee conservation campaign in the region.

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 (Brazil) and is being tracked by a team of local fishermen and former manatee hunters. During the first ten days after release he moved back and forth through channels in the flooded forest to nearby lakes, returning close to the release point. Freshly chewed aquatic grasses and plants were found near his main resting place.

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)

 

DENMARK

 

New Antillean Manatee Exhibit in Denmark. - The Zoo of Odense, Denmark, has just imported four Antillean Manatees from Georgetown, Guyana to accompany the solitary Henriette which, I understand, was born in the Nuernberg Zoo in Germany.

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/ >

 

FLORIDA

 

            To Downlist or Not to Downlist? - On 30 Oct. 2001, the U.S. Fish and Wildlife Service (FWS) approved the Third Revision of the Florida Manatee Recovery Plan, following public review of two prior drafts. These drafts updated the Second Revision of the plan, issued in 1996. As reported in recent issues of Sirenews, the main points of contention in the Third Revision involved the proposed population benchmarks that have to be achieved before downlisting (from Endangered to Threatened status) or delisting of manatees can be considered.

            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 March 22, 38 manatees have been killed by boats since the beginning of the year.  This figure compares to 12 watercraft mortalities at the end of March 2001.

Thus, the manatee is currently confronting precisely the situation which the FWS has declared (in its Biological Opinion on the CSLNG Development Project, Aug. 17, 1998, p. 7) to be a "critical threshold for the survival and recovery" of the species: an overall mortality rate at or exceeding 10% of the population. Under these circumstances, the FWS has declared (ibid., p. 6) that avoiding jeopardy to the species "depends on reducing" -- not merely avoiding further increases in -- manatee mortality. In turn, any serious effort to reduce overall manatee mortalities depends on reducing the number of manatees killed by boats, since "[t]he most significant problem faced by manatees in Florida is death or serious injury from boat strikes" (Recovery Plan, p. 23). Indeed, the FWS has declared (Recovery Plan, pp. 116, 121) that "[m]inimiz[ing] collisions between manatees and watercraft" is an "action that must be taken to prevent extinction" of the species. Until this is done, talk of downlisting seems premature.

 

JAPAN

 

Stomach Contents of Dugongs from Okinawa, Southern Japan, from 1992 to 2000. - Quantitative analyses of the stomach contents from four mature dugongs, two females and two males, obtained at Okinawa Island (two from the western coast on January 1996 and August 2000 and two from the eastern coast on May 1992 and April 2000, respectively) due to stranding and by-catch, were conducted under a collaborative study program with Okinawa Expo Aquarium and Mie University. The stomach contents of the four animals consisted almost entirely of seagrasses; annelids, ascidians and algae were very minor components of the contents. Each stomach contained 4 to 6 species of seagrass, and a total of 7 species of seagrass, belonging to 5 genera in 2 families, were identified from stomach contents and are known to occur commonly in coastal waters of Okinawa Island: Cymodocea rotundata, C. serrulata, Halodule uninervis, H. pinifolia, Halophila ovalis, Syringodium isoetifolium, and Thalassia hemprichii. However, the number and relative abundances of seagrass species from the stomach contents differed among the specimens. Halophila ovalis occurred in any stomach; S. isoetifolium was abundant in the stomachs from the eastern coast of the island, while C. serrulata was on the western coast. This evidence may suggest that the dugongs in Okinawan waters show little food preference, or dominant seagrass distribution is different between the western and eastern coasts of Okinawa Island. We will continue our study to analyze stomach contents of the dugongs, as well as to survey distributions of feeding trenches of dugongs, and species composition and abundance of seagrass beds in the coastal waters of the Island.  -  Kana AKETA (Aquatic Ecology Laboratory, Faculty of Bioresources, Mie University, 1515 Kamihama, Tsu, Mie 514-8507, Japan (tel.: +81-59-232-1211 (ext.2510), +81-59-231-9649 (ext.2510); fax: +81-59-231-9538; e-mail: <oe31236@muse.cc.mie-u.ac.jp>

 

NEW ZEALAND

 

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 “long branch attraction”). Dugongs are thought to be one of the closest living relatives of elephants. Adding the dugong sequences to the data set appears to break up the long elephant branch, thereby improving both the stability and the reliability of the mammalian tree.

            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 James Cook University in Queensland, Australia, showed that the two dugongs came from different areas, one from the seas around Brisbane and the other from further north.  -  Trish McLenachan (Allan Wilson Centre for Molecular Ecology and Evolution, Massey University, Palmerston North, New Zealand)

PHILIPPINES

 

Dugongs at Hinatuan, Surigao del Sur, Mindanao, Philippines. - My name is Rowan Byrne and I am an Irish marine and freshwater biologist working in Mindanao, Philippines. I am based in Surigao del Sur, in a small place called Hinatuan. It has extensive seagrass beds that are in exceptionally good condition -- the main reason why a small population of dugongs reside there.

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 Sairgao Island, Surigao del Norte.

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 Philippines. I have done this already in national papers, magazines both national and international, and have national and international TV channels documenting my work here, such as National Geographic Channel Asia.

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 Hinatuan Bay, Surigao del Sur, Mindanao.  -  An approximately 200-300kg male dugong (total length 197cm) was killed in Hinatuan Bay, not far from Mahaba Island and near the Municipal Fish Sanctuary. It was found floating dead inside a fish corral, and its abdomen was severely bloated. It appeared to have been dead 2-4 hours when the fish corral owner arrived at about 8 AM on 14 December 2001. It was taken to Mahaba Island for examination and photographs, where it was then buried and not eaten, despite its being Christmas -- showing that the people are concerned about the species and its conservation.

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.

 

VIETNAM

 

Observations of the Dugong in Con Dao National Park, Vietnam, and Recommendations for Further Research. - The dugong is perhaps the most endangered sea mammal in Vietnam.  There are few scientific records available about the distribution, abundance and ecology of dugongs in Vietnam.  Con Dao archipelago in southern Vietnam is the only location in the country where dugongs are regularly seen.  Local fisher interviews conducted in October 2000 in Con Dao (Cox, unpublished) revealed that dugongs were seen much more regularly and in greater abundance 10-25 years ago than they are now.  Whilst it appears that dugongs were often hunted specifically for meat and medicinal purposes, dugongs caught now are caught accidentally, and mortality is presumably as a result of drowning in nets.  Nine dugong carcasses were recorded in Con Dao between 1997 and 2000.  The results of this study add important information about this species to the sparse information currently available; further research is required particularly for Vietnam and neighboring countries.

The study area consisted of a number of small sheltered bays within the Con Dao archipelago, located approximately 85 km southeast of mainland Vietnam in the South China Sea.  The group of 14 islands has a mountainous landscape, and is largely forested and fringed with coral reefs and small patches of mangrove forest.  Con Dao National Park protects 80% of the total land area, including 5,998 ha of forest, 14,000 ha of sea and an additional sea buffer zone of 20,000 ha.  The present study was undertaken in three sites in Con Son Bay, although predominantly in Dat Doc Bay.

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 Vietnam, including Phu Quoc island, and Nha Trang.

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 Cleveland Bays, Queensland.  Australian Wildlife Research 5: 1-23.