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/ j Aenews.Ys
S Newsletter of the IUCN girenia specialist Group 1
OCTOBER 2007 Funded by the Ug Marine Mammal Commision NUMBER 48
IN T[I 1e.9U UE:
VOTE TO DOWNLIgT FLORIDA MANATEE FROM THREATENED TO ENDANGERED
POgTPONED (pg.2)
//RENAEW9 MOVING TO ELECTRONIC VERSION AFTER 20+ YEARS (pg. 2)
RISING TO THE CHALLENGE OF SCALE MISMATCH IN DUGONG CONSERVATION
In a recent paper in Ecology and Society, Cumming et al. (2006) points out the dangers of what they
refer to as scale mismatches in social-ecological systems. They hypothesize that many of the problems
encountered by societies in managing natural resources arise because of the mismatch between the scale of
management and the scale(s) of the ecological processes being managed.
The dugong has a huge range. Its extent of occurrence is some 140,000 km of coastline across 48
countries and includes tropical and subtropical coastal and island waters from east Africa to Vanuatu, between
about 26 and 270 north and south of the equator. Studies of dugong movements in Australia (Shepperd et al.
2006) indicate that individual dugongs can move hundreds of kilometers in a few days. The genetic evidence
(McDonald 2005) also indicates that the appropriate biological scale for dugong management is hundreds of
kilometers. Thus the potential for scale mismatch in dugong management is considerable and can only be
prevented by international collaboration.
The development of a Memorandum of Understanding (MoU) for the conservation of dugongs under the
auspices of the Convention on the Conservation of Migratory Species of Wild Animals (CMS), was agreed by a
recommendation adopted at the seventh CMS Conference of the Parties in 2002, and confirmed at the eighth
CMS Conference of the Parties in 2005. Two meetings in Bangkok in 2005 and 2006 developed and considered
a draft text of the MoU. The final draft proposal of the MoU and associated Conservation and Management Plan
were endorsed at the second meeting in Bangkok in May 2006. CMS circulated the adopted MoU and
Conservation and Management Plan to the range states for final comments and notification of intention to sign.
The comments received in response indicate that there were no major objections to the final draft. The texts are
now finalised and have been translated into French, Arabic and Chinese (see
http://www.cms.int/bodies/meetings/regional/dugong/pdf/docs_mtg3/Doc_04 Note of the Secretariat.pdf).
The MoU is a non-binding legal instrument that helps to protect and conserve dugongs. The associated
UNION INTERNATIONAL POUR LA CONSERVATION DE LA NATURE ET DE SES RESOURCES
I* SSCI INTERNATIONAL UNION FOR CONSERVATION OF NATURE AND NATURAL RESOURCES
Spc..i Sr,1,W.I Commi.sion Commission de la sauvegarde des especes-Species Survival Commission
Sirenews (ISSN 1017-3439) appears twice a year in April and October and is edited by
Cynthia R. Taylor and James A. Powell, Wildlife Trust, 1601 3rd Street S., Suite F, St. Petersburg, FL 33701 USA.
Sirenews is available online at www.sirenian.org and www.marinemammalogy.org.
Conservation and Management Plan is divided into nine objectives and an annex containing a list of examples
of specific activities that could be undertaken with a view to achieving these goals. Objectives relate to the
protection and conservation of the dugong and its habitat and the promotion of the implementation of the MoU.
The objectives also refer to improving awareness and education, the legal framework, as well as international
cooperation.
The MoU on the Conservation and Management of Dugongs and their Habitats throughout their Range
is scheduled to be signed in Abu Dhabi in the United Arab Emirates on October 31 2007. The signing will be
preceded by two concurrent workshops concerning the implementation of the Dugong Conservation and
Management Plan in: (i) East Indian Ocean and the Pacific Ocean and (ii) West Indian Ocean sub-regions. It is
intended that the outcomes of the two workshops and their integration will facilitate the implementation of the
MoU and the Conservation and Management Plan with support from the range states and other stakeholders,
such as the United Nations Environment Programme (UNEP) and various NGOs and IGOs dealing with dugong
conservation. Another advantage of these initiatives will be to identify research and implementing projects,
including financial support from governments and other international institutions.
I look forward to the MoU heralding a new era in dugong conservation, an era that recognizes the
dugongs do not recognize lines on maps and in which management and research are coordinated at scales
relevant to the dugong's biology. -Helene Marsh
References
Cumming, G. S., D. H. M. Cumming, and C. L. Redman. 2006. Scale mismatches in social-ecological systems:
causes, consequences, and solutions. Ecology and Society 11(1): 14. [online] URL:
http://www.ecologyandsociety.org/voll l/issl/artl4/
McDonald, B. 2005. Population genetics of dugongs around Australia: implications of gene flow and migration.
http://eprints.jcu.edu.au.elibrary.jcu.edu.au/1327/
Sheppard, J., Preen, A.R., Marsh, H, Lawler, I.R., Whiting, S., and Jones, R.E. 2006. Movement heterogeneity
of dugongs, Dugong dugon (Miller) over large spatial scales. Journal of Experimental Marine Biology
and Ecology 334 (2006) 64-83.
FLORIDA MANATEE VOTE POSTPONED
Following a request by Governor Charlie Crist, the Florida Fish and Wildlife Conservation Commission
postponed a vote to reclassify Florida manatees from "endangered" to "threatened" status. At their September
12th meeting the commissioners voted to defer the decision until at least December, when their next meeting
will take place in Key Largo, FL. The letter from Governor Crist, dated September 10th, urged the Commission
to postpone the decision to allow "the new members of the Commission more time to evaluate this complex
issue and ensure that they, along with the rest of the Commission, are fully prepared to vote on an item of such
gravity." Governor Crist referred to the manatee as "one of our state's most beloved natural resources", and
applauded the Commission for diligently working to resolve the status issues of the species. The final version
of the FWC Manatee Management Plan can be accessed at http://myfwc.com/imperiledspecies/plans/Manatee-
Mgmt-Plan.pdf. -CRT
BIBLIOGRAPHY AVAILABLE
Domning's 1996 Bibliography andIndex of the Sirenia and Desmostylia is now accessible online as part
of the Smithsonian Contributions to Paleobiology series at
http://www.sil.si.edu/SmithsonianContributions/Paleobiology/sc RecordSingle.cfm?filename= SCtP-0080.
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October 2007
It can be viewed in both PDF and full-text modes.
Efforts are continuing to make available online the underlying database, with post-1994 updates. It is
hoped that this will be accomplished in the next few months, thanks to the help of Caryn Self-Sullivan and a
volunteer programmer. -D. Domning
Sirenian Population Genetics
Conference
*USGS
SIRENIAN POPULATION GENETICS CONFERENCE
20-21 APRIL 2008, ORLANDO, FLORIDA
The US Geological Survey will be holding a Sirenian Population Genetics Conference in Orlando,
Florida on 20-21 April 2008. This meeting will be held just before the third triennial Florida Marine Mammal
Health Conference (http://conference.ifas.ufl.edu/marinemammal/index.htm) which will be convened at
Marineland (near St. Augustine), Florida between 22-25 April.
If you are interested in attending The Sirenian Population Genetics Conference please send me your
email address and I will add your name to a notification list. Registration details to follow shortly; early
registration before 17 March 2008 will be free, late registration after 17 March may be assessed a small fee.
The format of the genetics conference will include one day of detailed instruction by invited speakers on the
utility of genetic tools for determining population structure, and a second day consisting of 15 minute
presentations on sirenian genetics. Please contact me also if you are interested in submitting an oral
presentation or a poster. I would like a tentative title and a sentence about the importance to conservation of
your contribution. The final submission deadline for presentations will be 17 March. Transportation following
the conference on 22 April from Orlando to Marineland will be provided at a nominal rate. This venue will
afford a great opportunity for field biologists, researchers, managers, and clinicians to get together to discuss
issues related to sirenian conservation genetics and population management. -Bob Bonde (rbonde@usgs.gov)
FUTURE FORMAT OF SIRENEWS
We have received very little feedback following our request for comments in the previous edition of Sirenews
regarding the preferred format of the newsletter (electronic or hardcopy). Therefore, we are moving to an
electronic version of the newsletter as of this edition to save on printing and postage costs. We will continue to
print a small number of newsletters for libraries, etc. If the electronic version does not meet your needs please
contact the editors. -CRT
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October 2007
CONSERVATION PROSPECTS FOR THE WEST AFRICAN MANATEE
"Trichechus senegalensis"
Phase I of the West African Manatee Conservation Project will come to an end in December 2007.
Between November 2004 and that date, much will have been achieved. For the first time in the species' history,
regional action has been carried out in favour of its conservation, making it possible to improve knowledge of
the West African manatee. Thanks to the surveys conducted in the six PRCM countries (Mauritania, Senegal,
The Gambia, Guinea, Guinea Bissau and Sierra Leone) and the compilation of national reports in the other
African countries, a good database now exists on the status of the species, in particular its distribution,
populations, socioeconomic value, legal status and the recommendations for its conservation. Communication
tools have been developed for the general public (T-shirts, folders, posters, website), for experts (scientific
booklet under development) and for young people (school book under development). The development of a
communication strategy has made it possible to identify relevant actions for better sensitisation on the
importance of the species. Lastly, this phase will have allowed all the PRCM national partners to carry out field
work sensitisationn) and exchange visits.
Given the significant results achieved, a Project Phase II is being developed by Wetlands International.
This will be about implementing the regional strategy for the conservation of the manatee in the PRCM
countries, in particular by improving the legislation, developing research, communication and education, and
conducting practical actions. Furthermore, the launch of the West African Marine and Coastal Biodiversity
Network BIOMAC is planned in order to consolidate the achievements of the PRCM in the field of species
and habitat conservation. In recognizing that resources are transboundary, that key habitats and species face
similar challenges and that the same players are involved in their protection, the PRCM has agreed upon the
establishment of a West African Marine and Coastal Biodiversity Network to ensure the consistency of
interventions and promote experience exchanges. BIOMAC will make it possible to institute practical field
actions while building the capacity of local players who have to take responsibility for the future of their region.
-Dr. Mame Dagou DIOP (Wetlands International: dagouwet@gmail.com), and Ms. Emma Greatrix (Project
Development Officer, Wetlands International: emmawet@gmail.com)
CONSERVATION OF THE WEST AFRICAN MANATEE Trichechus senegalensis: WETLANDS
INTERNATIONAL SUPPORTS SCIENTIFIC RESEARCH
Still the least known living Sirenian, the West African Manatee is one of the "forgotten" mammals.
Presently, only a handful of scientists are conducting research on the distribution and biology of the species. It
is true that there is well-established relative knowledge about how the species is used, especially its socio-
ethnologic and economic values. In contrast, there is very little information about its biology (reproduction),
population, and distribution, posing major problems for monitoring the species. There is also plenty of
speculation about its reproduction and diet ("the manatee eats fish"). In order to overcome these shortcomings,
Wetlands International is supporting research on the species through partnership protocols with institutions in
the West African coastal sub-region and in Europe.
This is how a doctoral student at Ecole Inter-Etats de Sciences et Medecine Veterinaires (EISMV) in
Dakar has been conducting research on the bio-ecology of Trichechus senegalensis since January 2007. Her
work is focused on the comparison of two main types of manatee habitat and the gene characterisation of the
animals living in each of these. The investigation sites are the River Senegal Delta (a freshwater ecosystem) and
the Saloum Delta (a brackish water ecosystem). At the end of this work, we will have a better knowledge and
understanding of the biology of the species, as well as knowledge of the gene map of these populations.
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October 2007
To improve scientific communications on the species, Wetlands International is developing a booklet on
its biology. This document is being developed by a Masters level intern from the University of Groningen in
Germany. The booklet deals with issues pertaining to the systematics, morphology, dentition, diet, habitat and
distribution, reproduction and conservation status of the West African Manatee.
Finally, a manatee website is under development which will provide information on the species and the
project (http://www.tsenegalensis.org). -Dr. Mame Dagou DIOP (Wetlands International
dagouwet@gmail.com) and Ms. Prisca Ndour (EISMV, caprisnd@yahoo.fr)
BYCATCH OF NON-TARGETED MARINE SPECIES IN THE WESTERN INDIAN OCEAN:
PROBLEMS AND MITIGATION MEASURES.
From 13 to 15 November 2006, representatives from Western Indian Ocean (WIO) countries and from
other regions (USA, Australia, Sri Lanka) participated in a workshop to collate available information and assess
the potential impact of bycatch on non-targeted marine species in the WIO, with a focus on marine mammals
and turtles. This workshop was organized by the NGO Sea Sense, based in Tanzania, and by the University of
La Rochelle, France. The three-day workshop was held on the island of Mayotte (France) at H6tel Sakouli and
was funded by the Western Indian Ocean Marine Science Association through a MASMA (Marine Science for
Management) grant. The aims of the workshop were to: 1. bring together relevant marine mammal and turtle
scientists, fishery biologists, conservationists and managers in the region to share ideas and exchange
information on bycatch of non-targeted marine species in the WIO; 2. review the level of threat from fisheries,
both coastal and pelagic, in the WIO region; 3. discuss and resolve common issues relating to bycatch; 4.
discuss and resolve common issues relating to data collection and analysis, survey techniques, and specific
threats (other than by-catch) such as eco-tourism, pollution, habitat destruction/disturbance and boat collisions;
and 5. produce recommendations for research and management, fund-raising and future regional and
international collaboration. Presentations were given on the regional status and conservation of turtles and
marine mammals, in the context of fishery-related mortality. The workshop agreed that the coastal gillnet
fishery poses a serious threat to turtles, dugongs and cetaceans in the WIO region. There are currently no
measures to reduce bycatch in this fishery. Prawn trawling also poses a threat, particularly to turtles. It was
acknowledged that while turtles, dugongs, cetaceans and sharks are all impacted by fishing activities in the WIO
region, the highest priority is the dugong which is severely threatened from gillnetting and habitat disturbance.
The establishment of a regional dugong research and conservation programme has been identified as a high
priority. A rapid regional assessment of gillnet and prawn trawl fisheries was also considered a high priority to
assess the level of threat from these gears on non-targeted marine species. Practical ways to reduce bycatch
were identified, including convincing decision-makers of the importance of reducing bycatch due to the high
tourism value placed on marine mammals and turtles. Jeremy KISZKA1,2 & Catharine MUIR3
(Convenors) (1 CRELA (Centre de Recherche sur les Ecosystemes Littoraux Anthropis6s), UMR 6217, CNRS-
IFREMER-Universit6 de La Rochelle, Avenue Michel Cr6peau, F-17071, La Rochelle, France. Email :
jeremy.kiszka(wanadoo.fr; 2 Direction de l'Environnement et du D6veloppement Durable, Collectivit6 D6partementale
de Mayotte. BP 101 F-97600 Mamoudzou, Mayotte; Sea Sense, P 0 Box 105044, Dar es Salaam, Tanzania)
girenews No. 48
October 2007
LOCAL NEWS
DOMINICAN REPUBLIC
Antillean Manatees in Cafio Estero Hondo, Dominican Republic. There have been few scientific
studies on manatees in the Dominican Republic (Belitsky & Belitsky, 1980; Ottenwalder, 1995; Pugibet &
Vega, 2000). Nevertheless, manatees are found around the country, especially along the north coast. Cafio
Estero Hondo is a coastal saltwater lagoon, located in the northwest coast. It is connected via a narrow entry
channel to a shallow bay protected by a reef, included within the Marine Mammal Sanctuary of Estero Hondo,
created in 2004. With the aim of gathering information on the actual status of manatees in the Sanctuary, and
contributing to the knowledge and management of the species, a preliminary study was started in January 2007
by the Centro de Investigaciones de Biologia Marina (CIBIMA) of the Universidad Aut6noma de Santo
Domingo (UASD). The study is based on interviews with locals, habitat sampling for baseline environmental
variables, and manatee boat surveys using a non-invasive 30 minute point-scan methodology in selected
stations, following Self-Sullivan et al. (2003).
Locals are knowledgeable about manatees. Of 138 interviews carried out in six communities near the
lagoon, 95% of respondents identified manatees correctly and 86% have seen them personally. A total of 173
manatee sightings were reported by interviewees in the past. Analysis of the death cases reported show that at
least 11 to 12 manatees died in the study area between 1996 and 2007, from both natural causes and illegal
hunting. Excluding the death cases and reports from people who did not see the manatees personally or did not
remember the exact place where the sighting occurred, 61% of 119 reports have occurred in Cafio Estero
Hondo. According to 67% of respondents, manatees are present during all months of the year, and 76% believe
that they travel daily in and out of this coastal lagoon. All respondents are aware of the status of the manatee as
a protected species, and 70% believe that the manatee population has increased in the last 10 years. Of the
respondents who stated the reason for the increase, the most popular answers were: due to an increase in
protection efforts (45%), and due to reproduction (23%).
In terms of habitat characterization, surface water temperature averages 30.4 C and the average depth is
1.91 m. Salinity can vary from 9 to 37 %o due to rains and naturally occurring freshwater effluents, of which six
have been identified. The dominant seagrass species are Thalassia testudinum and Syringodiumfiliforme, but
Halodule wrightii and Halophila decipiens are also present.
During 2007, 147 hours of effort have resulted in 49 sightings (18 within the point-scan sampling design
and 31 opportunistic). Of the latter, 12 were from fixed point land surveys. The maximum number of manatees
seen simultaneously during one sighting was nine, including at least three and possibly four calves. Manatees
were most often observed at either end of the entry channel to the lagoon, where seagrass was more abundant.
Manatees were frequently observed in a resting hole identified in the west arm of the lagoon. Although illusive
and evasive, manatees have been observed feeding, resting, traveling, socializing and milling within the Cafio
Estero Hondo. Manatees were observed during each month from March to August 2007. More information on
distribution and habitat use will be available as field work is completed by the end of this year.
To answer questions regarding individuals and their movements, we would like to start a manatee
tagging and tracking project. We are seeking training opportunities and partnership with experts in order to
achieve it. This preliminary study was made possible with the support from the Secretaria de Estado de
Educaci6n Superior Ciencia y Tecnologia (SEESCyT) and the Fundaci6n Brugal. We are grateful to Dr. Caryn
Self-Sullivan for training in the use of the point-scan methodology, expert advice on our research design and
field work, and her continuous support of the project. -Hayd6e M. Dominguez Tejo (Centro de Investigaciones
de Biologia Marina CIBIMA. Universidad Aut6noma de Santo Domingo. Aristides F. Cabral, esquina Ortega
Frier. Ciudad Universitaria. Santo Domingo. Tel. 809-686-3250. E-mail: hdominguezt@gmail.com)
girenews No. 48
October 2007
References
Belitsky, D. W. & C. L. Belitsky. 1980. Distribution and abundance of manatees Trichechus manatus in the
Dominican Republic. Biological Conservation. 17:313-319.
Ottenwalder, J. A. 1995. Situaci6n del manati en la Republica Dominicana. Dominican Business (3a Etapa)
mayo-junio 1995. 32:41-44.
Pugibet, E. & M. Vega. 2000. Informe sobre el Manati Antillano (Trichechus manatus) en la Republica
Dominicana. Informe presentado al Secretario de Estado de Medio Ambiente y Recursos Naturales Dr.
Frank Moya Pons. Santo Domingo, R. D. 37 p.
Self-Sullivan, C., G.W. Smith, J.M. Packard & K.S. LaCommare. 2003. Seasonal occurrence of male Antillean
manatees (Trichechus manatus manatus) on the Belize Barrier Reef. Aquatic Mammals 29:342-354.
EAST AFRICA
Dugongs in eastern Africa: balancing on the brink. The dugong (Dugong dugon) is the only
herbivorous mammal that is strictly marine, and the only member of the family Dugongidae. This is the most
abundant sirenian, and it occurs in at least 48 countries and territories of the tropical and subtropical Indo-
Pacific region, from east Africa to Vanuatu, covering a coastline of approximately 140,000 km (Marsh et al.,
2002). Of the four extant sirenians, dugongs have the largest range and population size. However, due to the
coastal habitat of dugongs, they face many threats including hunting, bycatch in fishing nets (especially
gillnets), habitat degradation and pollution of coastal ecosystems. At the global scale, the dugong is currently
classified as Vulnerable by IUCN. However, its conservation status is highly variable throughout its range with
the largest populations occurring in Australia, south-east Asia and in the Arabian Gulf (Marsh et al., 2002).
The eastern Africa coast marks the western-most boundary of the dugong's global range. This
geographical area has a mainland coast of over 11,000 km and is home to some of the world's most important
coastal and marine environments and resources providing important feeding and calving grounds for dugongs as
well as other endangered marine species. Two marine ecoregions have been identified in the region representing
globally outstanding examples of marine and coastal biodiversity: the Eastern Africa Marine Ecoregion and the
Western Indian Ocean Marine Ecoregion (WWF EAME, 2004). The region has a coastal population of over 30
million people who are among some of the poorest in the world and whose livelihoods are largely dependent on
marine and coastal resources such as inshore fisheries and mangroves.
Historical records indicate that dugongs were abundant in the coastal waters throughout eastern Africa.
However, recent investigations show that dugongs have declined dramatically in recent decades, especially
during the 1970s and 1980s. In 2001, in recognition of the need for effective management of dugongs in the
western Indian Ocean, Decision CP.3/4 of the third Conference of Parties of the Nairobi Convention, requested
regional and international organizations to facilitate the development of a regional initiative to protect the
dugong. Consequently, UNEP through the Nairobi Convention, with assistance from WWF and IUCN,
provided support for countries of the region, i.e. Kenya, Tanzania, Mozambique, Seychelles, Mayotte, Comoros
and Madagascar, to carry out a rapid assessment of the status, distribution and threats to dugongs.
Methods included reviews of existing literature, questionnaire interview surveys, opportunistic sightings
and dedicated sighting surveys. Consultation with researchers, conservation practitioners and other relevant
contacts in each country was undertaken. Interviews were conducted with fishers, government personnel, diving
and aircraft operators in each country of the region. These interview surveys were conducted from June to
December 2003. Dedicated aerial surveys were only conducted in Mozambique, especially in Maputo Bay
(between 1992 and 2001), Bazaruto Bay and neighboring areas (1990, 1992, 1995, 1999, 2001 and 2002) and
Inhambane Bay (October 1994) and more recently, dedicated aerial surveys have been conducted around the
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October 2007
island of Mayotte from July to November 2005 and in Tanzania in early 2006 (WWF EAME, 2004; Kiszka et
al., 2007).
Results indicate that dugongs still occur, but in very low numbers which may not be viable. The most
important population seems to be around the Bazaruto archipelago in Mozambique, with a population of at least
100 animals. Dugongs also occur in Tanzania (especially in the Rufiji Delta area), Kenya, Madagascar (along
the west and north-east coasts), Moheli Island (Comoros), in the lagoon of Mayotte (< 10 individuals) and in the
Aldabra atoll, Seychelles (at least 4 individuals). Several observations suggest that breeding still occurs, such as
in Tanzania (3 calves caught in gillnets in the Rufiji /Mafia area since 2004) and Mayotte (live mother-calf pairs
observed during aerial surveys in 2005; Kiszka et al., 2007).
In the past when dugongs were more abundant in the region, they were often deliberately hunted for
their meat (a prized source of protein), oil and bones. Today, with populations severely depleted, captures are
mostly incidental, although the value of the meat remains an incentive to kill a live dugong caught in a net.
Entanglement in legal inshore artisanal set or drift gillnets currently poses the greatest threat to dugongs in the
region. Large mesh nets of 12-18 inches are the most threatening fishing gear. In all countries, the decline in
dugong populations appears to be related to the introduction and increased use of nylon filament gillnets (WWF
EAME, 2004). The shallow, near-shore habitat requirements of dugongs and their slow rate of reproduction
render them particularly vulnerable to human activities, including artisanal inshore fishing, habitat disturbance
and hunting, and general pressures from a rapidly growing coastal population. Reducing mortality levels is a
major challenge, particularly in low income nations and in areas where populations are so small and
fragmented. Seagrasses, which comprise the main diet of dugongs, are sensitive plants, prone to human impacts
both directly (trawling, mining) and indirectly (inland and coastal clearing inducing erosion and sedimentation,
and pollution by heavy metals and organic pollutants). On the Zanzibar Island of Unguja in Tanzania, rapid and
unplanned coastal development, primarily for resorts, is causing severe erosion which in turn can have a serious
impact on seagrass beds. Near-shore licensed prawn trawling in Kenya, Tanzania and Mozambique in areas
where dugongs are most commonly seen is impacting seagrass beds and therefore their foraging areas. Seagrass
is also susceptible to large-scale impacts by natural physical processes such as cyclones which occur seasonally
in Mozambique and Madagascar. Although dugongs are protected by national legislation in all the east African
countries, enforcement of these laws is wanting. The capacity of mandated government agencies responsible for
enforcement of such laws is often lacking, with efforts hampered by limited personnel and lack of resources.
Dugong populations are now small and isolated from one another. Several dugong initiatives have since
been undertaken in some countries in eastern Africa including aerial surveys in Mozambique, Tanzania and
Mayotte and comprehensive interview surveys in Tanzania and the Comoros archipelago (especially in Moheli).
A regional Indian Ocean South-East Asia dugong Memorandum of Understanding on their conservation has
also been drawn up and in November 2006, a regional workshop was convened in Mayotte on Incidental
Catches of Non Targeted Marine Species in the Western Indian Ocean highlighting ways to mitigate the threat
to endangered marine species, including dugongs, from incidental net captures (Kiszka & Muir, 2007).
The most effective short-term conservation measure will be reducing the threat from incidental net captures
through restriction or banning of threatening fishing gear (particularly gillnets) and the provision of alternative
gear or livelihoods. In the medium to long-term, education, training of local communities and relevant
government bodies and the establishment of community-managed dugong sanctuaries will also play a valuable
role. Regional cooperation is imperative to coordinate efforts, target resources and encourage the development
of a more robust scientific approach. Furthermore, collaborative scientific investigations are needed to provide
accurate data on the status, distribution, abundance and ecology of dugongs in the region. In the western Indian
Ocean region, very few dedicated surveys have provided accurate estimates of dugong abundance. In many
areas, dugong habitats need to be identified. As an example, along the west coast of Madagascar, large seagrass
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October 2007
areas have never been explored and may represent key areas for dugongs in the region. Regional projects are
now under consideration to contribute to the recovery of dugongs in eastern Africa. -Catharine Muir' and
Jeremy Kiszka2'3, (1 Sea Sense, P 0 Box 105044, Dar es Salaam, Tanzania; 2 CRELA (Centre de Recherche
sur les Ecosystemes Littoraux Anthropises), UMR 6217, CNRS-IFREMER-Universite de La Rochelle, Avenue
Michel Crepeau, F-17071, La Rochelle, France. Email: jeremy.kiszka@wanadoo.fr;3 Direction de
l'Environnement et du Developpement Durable, Collectivite Departementale de Mayotte. BP 101 F-97600
Mamoudzou, Mayotte)
References
Kiszka, J. & Muir, C. (Eds.) (2007) Incidental catches of non-targeted marine species in the Western Indian
Ocean: problems and mitigation measures. Workshop proceeding. 13-15th November 2006, Mayotte,
France. Western Indian Ocean Marine Science Association (WIOMSA). 111 p.
Kiszka, J., Muir, C. & Jamon, A. (2007) Status of a marginal dugong (Dugong dugon) population in the lagoon
of Mayotte (Mozambique Channel), in the western Indian Ocean. Western Indian Ocean Journal of
Marine Science, 6, 111-116.
Marsh, H., Penrose, H., Eros, C. & Hughes, J. (2002) Dugong: status report and action plans for countries and
territories. Early Warning and Assessment Report Series. UNEP.
WWF Eastern African Marine Ecoregion (2004) Towards a Western Indian Ocean Dugong Conservation
Strategy: The Status of Dugongs in the Western Indian Ocean Region and Priority Conservation
Actions. Dar es Salam, Tanzania.
INDONESIA
New initiative to develop a National Dugong Conservation Strategy and Action Plan for Indonesia.
Recently a new initiative was announced to develop a National Dugong Conservation Strategy and Action Plan
for Indonesia. After the publication of the Global Status Report and Action Plans for countries and territories in
its range (Marsh et al, 2002), several initiatives have been taken to develop more detailed National Dugong
Conservation Strategies. The best known example to date in SE Asia is the Strategy document produced by
WWF Philippines during a three-day seminar and workshop held in Davao City from 6-8 November 1998
which marked a pivotal phase in the history of dugong conservation in the Philippines.
In Indonesia little scientific information is available on the abundance, distribution and behaviour of
dugongs. The size of dugong populations is unknown (Marsh et al., 2002). In the 1970s the dugong population
was estimated to be around 10,000. In 1994, the population was estimated to be around 1,000. Both population
estimates are guesses and should not be considered as evidence for a decline in the intervening period, although
studies have indicated a dramatic decline in numbers in specific areas such as the Am Islands (De Iongh, 1996;
De Iongh et al, in press). Dugongs have been reported from Balikpapan Bay and suitable dugong habitats have
been identified in other parts of the East Kalimantan coastal area (Marsh et al., 2002).
The main objective of this programme is to use the available scientific data on dugong distribution and
ecology in Indonesia to draft a National Dugong Conservation Strategy and Action Plan for the remaining
dugong populations in Indonesia and to initiate its implementation. The programme will have a high degree of
stakeholder participation and the expected output (the strategy) is considered as important as the process to
reach this output. This programme is proposed for implementation under the umbrella of the UNEP Regional
Seas Programme and the UNEP Convention on Migratory Species (CMS) with Indonesian-Dutch collaboration.
For the development of the strategy a phased approach will be followed, covering at least 2007 and 2008.
Additional objectives of the proposed programme are defined as follows:
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October 2007
1) Identification of the most recent conservation status of dugong populations in Indonesia, including an
update of the main dugong distribution and population size.
2) Identification of available seagrass habitat and associated dugong grazing swards, to estimate maximum
sustained population size.
3) Identification of the main threats to dugong survival.
4) Definition of strategic objectives and priority actions for dugong conservation and management.
The Global Status report and Action Plans for countries and territories in the dugongs range as published by
Marsh et al. (2002) will be used as a background document. Linkages will be made with other initiatives in the
region, notably the Australian sponsored initiative to develop a Memorandum of Understanding under CMS on
the conservation and management of dugongs and their habitats throughout their range and an associated
conservation and management plan. Consistency and cross-referencing with the provisions of this instrument,
currently in its final stage of negotiation, will be searched to the fullest extent possible. Other National Dugong
Conservation Strategies (e.g. Philippines) will also be considered. The dugong is considered to be a flagship
species for coastal conservation efforts in the region, including environmental education and raising awareness.
Coastal areas throughout Asia are threatened by habitat destruction through unsustainable fishing practices
(dynamiting, the use of cyanide), while inshore seagrass meadows are impacted by land based activities
resulting in excessive sedimentation. The Research Centre of Oceanography in Jakarta and the Institute of
Environmental Sciences in Leiden have signed a Memorandum of Understanding (MOU) for the development
of the National Dugong Conservation Strategy and Action Plan for Indonesia.
Under this MOU a Joint Steering Committee has been established, which gives guidance and technical
advice to the coordinators of the project. The Director of the Research Centre of Oceanography in Jakarta
chairs the Steering Committee and members have been selected during the first months of the project, based on
expertise in a relevant field, for development of the National Dugong Conservation Strategy and Action Plan.
Expatriate (CML Leiden, The Netherlands) and Indonesian researchers (i.e. Research Centre for
Oceanography in Jakarta), institutions (i.e. Ministry of Marine Affairs and Ministry of Environment in Jakarta),
students (i.e. UNMUL in Samarinda, UNHAS in Makassar), and national and local NGO's will work together
to develop the National Dugong Conservation Strategy and Action Plan for Indonesia during 2007 and 2008.
The anticipated outputs at the end of 2008 will be a first draft of the plan, including an identification of major
gaps in information. It is also the intention to implement additional aerial and/or ground surveys to update our
knowledge of dugong distribution during 2007 and 2008, if additional funds are found. In addition, stakeholder
workshops will be organised and a communication plan will be set in place if additional fundraising is
successful.
Ground surveys, aerial surveys and interviews with local fishermen conducted during 1990 to 2005 have
already revealed the presence of dugongs in the coastal waters of Maluku Province, Java island, Bali island,
lesser Sunda islands, Sulawesi, East Kalimantan and West Papua. Dugongs in Indonesia depend to a large
degree on intertidal seagrass meadows situated on the narrow coastal shelf. Most of these meadows were
situated in front of coastal villages. Field observations, the use of satellite telemetry and interviews with local
villagers showed that most of the dugongs investigated consistently foraged on a limited number of two to three
"core areas" (De Iongh et. al., 1998; De Iongh et al., in press). Rotational grazing in grazing swards is a
common phenomenon by small feeding assemblages and individual dugongs returned to the same feeding plots
at regular intervals of time. These feeding strategies will have to be taken into account when designing
protected areas and community based conservation schemes for the remaining dugong populations in Indonesia
(Harkes, 1998). The coordinators hope to report on a regular basis in SIRENEWS on the progress of this
important initiative. -Hans de longh and Wawan Kiswara (Delongh@cs.com)
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October 2007
References
De Iongh, H.H., W. Kiswara and W. Kustiawan (in press). A review of fifteen years research on the interaction
between dugongs (Dugong dugon Muller 1776) and intertidal seagrass beds in Indonesia,
HYDROBIOLOGIA.
De Iongh, H.H.,P. Langeveld, and M. van der Wal. 1998. Movement and home ranges of
dugongs around the Lease islands, East Indonesia. Marine Ecology, 19 (3):179-193.
De Iongh, H.H. 1996. Current status of dugongs in Indonesia, In: The Aru Archipelago:
plants, animals, people and conservation, H.P. Nooteboom (Ed.). Amsterdam: Nederlandse
Commissie voor Internationale Natuurbescherming, pp. 75-85.
Harkes, I. 1998. Institutional resilience of Sasi Laout, a local management system in
Ambon, Indonesia. Seminar proceedings IIAS/NIAS Seminar on Co-Management of Natural
resources in Asia: A comparative perspective, 16-18 September 1998, Isabela State Unversity,
Cabagan, Philippines.
Marsh, H., Penrose, H., Eros, C. and Hugues, J. 2002. The dugong (Dugong dugon) status report and action
plans for countries and territories in its range. UNEP Early warning and assessment report series 1: pp
162.
MEXICO
Manatees at freshwater systems in Southeastern Mexico. Research: Manatees in Mexico had been
mostly studied along the Caribbean coasts of the country, within estuarine systems (Morales-Vela and Olivera-
G6mez, 1997; Morales-Vela et al., 2000). This is because it is relatively easy to conduct aerial or boat surveys
and to capture manatees for radio tagging, health assessments or genetic sampling. However, populations of
manatees at freshwater systems associated with major rivers flowing into the Gulf of Mexico, for example
Usumacinta and Grijalva (whose joint runoff is more than 30% of the total in Mexico), in the Mexican states of
Tabasco, Chiapas and Campeche, seems to be larger than those of the Caribbean coasts (Colmenero and Hoz,
1986). Previous studies (Alvarez, et al., 1986; Colmenero and Hoz, 1986; Arriaga-Weiss and Contreras-
Sanchez, 1993) showed that manatees are frequently sighted all along the waterways and lake systems
connected with the Usumacinta and Grijalva rivers, which serve as main dispersal corridors for manatees.
A research program was initiated in 2005 in the Mexican state of Tabasco to provide a technical base for
studying and managing the manatee populations in the region, motivated by threats like stranding and mortality
of free ranging and captive manatees, cases of orphaned calves, illegal hunting and general habitat deterioration.
Interviews with local people and fishermen, as well as navigation along rivers, channels and lakes, showed that
manatees are well distributed throughout the region, including the areas with extended lake systems where
manatees are most frequently sighted. Almost all local people interviewed correctly identified and described
manatees and had experienced encounters with them. In addition to visual examination of water courses in
search of manatees, we tested and evaluated a side scan sonar system, which had been proven to detect
manatees as far as 70 feet from each side of the boat.
In 2006 we made the first attempt to capture and radio tag manatees within freshwater systems of
Mexico. After some trials we developed a successful method for capturing manatees in this habitat. We
encircled manatees in large nets and waited until the manatees tried to escape by pushing the net with their
head. At that point the bottom of the net was pulled up, entangling the manatees in the net. The manatees were
then restrained at one side of the boat for a few minutes until field personnel were prepared to pull the animal
into the boat. The manatees suffered some superficial scrapes, however the entire procedure only lasted
approximately 10 minutes with minimal struggling from the animal. We used VHF tags similar to those
developed by Sirenia Project in Florida, USA, and implanted AVID pit tags for identification. Blood samples
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October 2007
were taken from each animal at the brachial vascular bundle (Dierauf and Gulland, 2001). Before releasing the
manatees back into the water a fluke skin sample was gathered for genetic analyses.
With this procedure, from April 2006 to August 2007 we captured and radio tagged 13 manatees in the
region. Eight were tagged in "Laguna de Las Ilusiones", an isolated urban lake in the urban area of the capital
city of the state of Tabasco, and five at the southeastern zone of the state, four in the lake of "La Barbona" in
the lake system of Leona Vicario and one at Arroyo San Pedro, a stream which drains to the Usumacinta river.
Results from blood samples show that the manatees were healthy when captured. We are evaluating their
movements.
Conservation
Hunting is rare in the region, but when caught in nets manatees are sometimes killed and used for meat.
However, other factors are causing more concern, such as natural or artificial closing of lake systems where
manatees become isolated and where interbreeding, temporal food deprivation and high temperatures result in
health problems within these isolated populations. Opening areas for agriculture and poultry changed more than
85 % of the original landscape in the last 50 years in the region and has caused sedimentation, eutrophication,
and pollution in the lake and river systems.
In addition to these problems, part of the region is one of the most important land areas for oil and gas
extraction in Mexico, and their daily and temporal activities could cause injuries to animals, such as
transportation of personnel (in fast boats) and machines and products (in large cargo boats). There is also a
latent danger for manatees in the case of explosions or spills of gas and oil pipes. Manatees in captivity is
another concern. There are two parks with captive manatees kept in freshwater ponds where the only
management procedure is feeding, except when the animals get sick. Besides these two parks, there are other
areas were isolated manatees are kept and were management procedures should be implemented.
In late 2006 and early 2007, six workshops were conducted with children in the first and second grade of
the primary school in communities located north of the study area, within a protected natural area (The
Biosphere Reserve of Pantanos de Centla). The aim of these workshops was to evaluate if children recognize
the manatee and to teach them basic facts about manatees, their importance, and activities that threaten manatee
conservation in the area. Interchange of information with the children was very useful, for example, some kids
said they had eaten manatee meat recently!
The area is an important hotspot for conservation of Antillean manatees due to their extent and numbers,
so research and environmental education must continue in order to ensure the survival of this species in the long
term. Le6n David Olivera-G6mez (Divisi6n Academica de Ciencias Biol6gicas, Universidad Juarez
Aut6noma de Tabasco. carretera Villahermosa-Cardenas Km. 0.5, S/N, C.P. 86150. Villahermosa, Tabasco,
Mexico. E-mail: leon.olivera@dacbiol.ujat.mx)
References
Alvarez C., A. L. Aguayo and J. Mujica. 1988. Observaciones sobre el manati Trichechus manatus, en la region
media del Usumacinta, Tabasco. En Ecologia y conservaci6n del Delta de los Rios Usumacinta y
Grijalva. Memorias. Institute national sobre Recursos Bi6ticos (INIREB)-Divisi6n Regional Tabasco.
Mexico. p. 617-624.
Arriaga W. y S. Contreras. 1993. El manati (Trichechus manatus) en Tabasco. Informe Tecnico Universidad
Juarez Aut6noma de Tabasco. Division Academica de Ciencias Biol6gicas. Villahermosa Tabasco,
Mexico. 73p.
Colmenero R., L.C. y E. Hoz Z. 1986. Distribuci6n de los manaties, situaci6n y su conservaci6n en Mexico.
Anales Inst. Biol. Univ. Nac. Aut6n. Mexico. Ser. Zool. (1985) 56(3): 955-1020.
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October 2007
Morales-Vela, B. y L. D. Olivera-G6mez. 1997. Estado actual de la poblaci6n de manaties en la costa norte y
centro-norte del estado de Q. Roo, Mexico. Anales Inst. Biol. Univ. Nac. Aut6n. Mexico. Ser. Zool.
68(1): 153-164.
Morales-Vela, B., D. Olivera-G6mez and J. E. Reynolds. 2000. Distribution and habitat use by manatees
(Trichechus manatus manatus) in Belize and Chetumal Bay, Mexico. Biological Conservation 95: 67-
75.
SIERRA LEONE
The distribution and exploitation of manatees in Sierra Leone: survey report. The following text is
the summary of a report contributed to the management plan for West African Manatee (Trichechus
senegalensis) population conservation. For the entire report (in French), please contact the authors.
From 3-22 October 2006, we gathered information about the manatee's population from fishing
communities situated along the littoral coast of Sierra Leone and its three main estuaries. As a continuation of
the survey methodology used by Reeves in 1986 (Reeves et al, 1988), information was collected regarding 1)
the presence and distribution of manatees along the littoral coast, 2) the ecology, biology and manatee
behaviour, 3) the local perception about manatees and 4) the types of exploitation. Based on 20 interviews
discussing the local knowledge of manatees in the 18 villages investigated, we determined that:
1. The manatee appears to be widely distributed in the major rivers and estuaries of Sierra Leone.
2. Some villagers know precisely the ecological and/or biological behaviour of the manatee.
3. Manatees are mostly considered by the local villagers as a food resource and a destructive animal.
4. Manatees are killed by occasional captures using classic fishing methods and by specific captures
using specially-designed traps and in a special large-mesh net set.
In order to contribute to the management plan for West African manatee population conservation in Sierra
Leone currently coordinated by Wetlands International, our recommendations following this preliminary study
are divided in three main categories:
1. The need for improvement of scientific knowledge of the West African manatee and additional
information on the types of exploitation in Sierra Leone.
2. Educating the authorities and the local communities on the value of the manatee and the need to
protect the manatee.
3. The creation of sanctuaries and protected areas.
This project was carried out in partnership by Noe conservation, FIBA and the Ministry of Fisheries of Sierra
Leone and received financial support from the Fondation TOTAL pour la biodiversity et la Mer. -Antoine Cadi
and Jean-Marie Ballouard (Nod Conservation Association, tel : 00 33 615 77 511 67,
www.noeconservation.org, acadi@noeconservation.org, jeanmarieballouard@hotmail.com)
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October 2007
ABSTRACTS
THE SPATIAL ECOLOGY OF DUGONGS: APPLICATIONS TO CONSERVATION MANAGEMENT
PhD Thesis submitted by James Sheppard
ABSTRACT
Dugongs are large primary consumers of seagrass communities, and thereby shape the diversity, structure, and dynamics of
these extensive ecosystems. The dugong is listed as vulnerable to extinction at a global scale. Because dugongs are seagrass
specialists, understanding the interaction between dugongs and their seagrass habitats is crucial to their conservation. Habitat use by
dugongs is beginning to receive greater attention by managers and ecologists, but a spatially-explicit model capable of predicting
usage by dugongs based on attributes of those habitats is lacking. Studying the interaction between dugongs and their seagrass food
requires knowledge of the movements and diving behaviour of dugongs at scales relevant to both dugongs and managers. Information
is needed on dugong spatial patterns, including movement behaviours and habitat use, across domains of scale. Multi-scale approaches
to dugong research have not been possible in the past because of the difficulties in observing dugongs directly and the low resolution
of telemetric equipment.
My project capitalised on recent technology incorporating accurate GPS technology into tracking equipment to monitor the
habitat use of wild animals at very high resolution (<10 m). Advances in geographic information systems (GIS) and spatial modeling
enabled habitat selection by satellite-tracked dugongs to be analysed in a high-resolution, spatially explicit manner. I used hierarchical
scales of spatial analyses to assess the relative importance of different seagrass meadows and parts of meadows to dugongs at scales
that are suitable for informing policy concerning the management of human activities. My central research hypotheses were that: (1)
dugongs forage like terrestrial mammalian grazers in that they prefer habitats where their foraging efficiency is greatest and (2)
patterns of dugong movements and habitat use across spatial scales are intimately linked to the availability and distribution of quality
seagrass forage.
I investigated the mechanisms that produce the large-scale distribution and movement patterns of dugongs by reanalysing the
results of historical aerial surveys and satellite tracking conducted by earlier researchers in combination with new data from my GPS
telemetry of 20 dugongs in sub-tropical and tropical waters of Queensland and the Northern Territory, Australia. The mean patch size
supporting high relative density (> 0.1 dugongs/km2) of dugongs over 20 years along the urban coast of Queensland was 77 km2 ( 4
s.e.). Hence, at regional and landscape scales (> 100 kinm2) dugongs select habitat at the level of individual bays along the coast. The
tracked dugongs were followed for periods ranging from 15 to 551 days and exhibited a large range of individualistic movement
behaviours; 26 individuals were relatively sedentary (moving < 15 km) while 44 made large-scale movements (> 15 km) of up to 560
km from their capture sites. Male and female animals, including cows with calves, undertook large-scale movements (LSM; > 15 km).
At least some of these movements were return movements to the capture location, suggesting that such movements were
ranging rather than dispersal movements. Large-scale movements included macro-scale regional movements (> 100 km) and meso-
scale inter-patch local movements (15 < 100 km) and were qualitatively different from tidally-driven micro-scale commuting
movements between and within seagrass beds (< 15 km). Large-scale movements were rapid and apparently directed. Tracked
dugongs rarely traveled far from the coast (mean max distance = 12.8 s.e. 1.3 km). Dive profiles from the time-depth recorders
suggest that dugongs make repeated deep dives while traveling rather than remaining at the surface. Some animals caught in the high
latitude limits of the dugongs' range on the Australian east coast in winter apparently undertook long distance movements in response
to low water temperatures, similar to the seasonal movements of Florida manatees.
A 24 km2 seagrass meadow in Hervey Bay, Queensland, Australia was confirmed as important dugong habitat on the basis of
the tracking data. Marine videography, Near-infrared Spectroscopy (NIRS) and Geographic Information Systems (GIS) were used to
survey, analyse and map seagrass species composition, nutrient profile and patch structure of the meadow at high resolution (200 m).
Five species of seagrass covered 91 % of the total habitat area. The total above and below-ground seagrass biomass was estimated to
be 222.7 s.e. 19.6 t dry-weight. Halodule uninervis dominated the pasture (81.8 %, 162.2 t), followed by Halophila ovalis (35.3 %,
16.5 t), Zostera capricorni (15.9 %, 22.2 t), Halophila spinulosa (14.5 %, 21.9 t), and traces of Halodule pinifolia. Because the
distributions of the various seagrass species overlapped, their combined percentage totaled > 100 % of the survey area. The seagrass
formed a continuous meadow of varying density.
For all seagrass species, the above-ground component (shoots and leaves) possessed greater total nitrogen than the below-
ground component (roots and rhizomes), which possessed greater total starch. Because of the relatively low intraspecific variation in
nutrient composition, nutrients were concentrated according to seagrass biomass density. H. uninervis was the most nutritious seagrass
species because of its higher whole-plant nitrogen (1.28 s.e. 0.05 % DW) and starch (6.42 s.e. 0.50 DW %) content. H. uninervis
formed large, clustered patches of dense biomass across the pasture and thus nitrogen and starch were concentrated where H. uninervis
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October 2007
was prevalent. These survey and analytical techniques enabled me to rapidly, economically and accurately quantify and characterise
seagrass habitat at scales relevant to a large forager.
I used GIS and spatial statistics to identify the role of physical environmental characteristics in determining the activity
patterns and fine-scale space-use of dugongs tracked in coastal and deepwater seagrass habitats using GPS telemetry. A seagrass
meadow was defined as a core dugong habitat if more than 10 days of satellite location fixes were obtained from an individual animal
occupying an area <100 km2. Habitats were categorised as inshore/intertidal or offshore/subtidal depending on their distance to the
shore and the water depth. Inshore/intertidal habitats had a shallow component that was exposed at low-tide. Offshore/subtidal habitats
were at least 5 km from the nearest mainland and were at least 3 m deep at mean low water spring tide (MLWS). Location fixes
acquired from dugongs tracked in coastal habitats exhibited significant circadian rhythms, with fewer locations during the morning
than during late afternoon/night. GPS location fixes could only be acquired when the transmitter was at the surface. Such periods are
typically brief, as when the animal surfaces to breathe. More GPS locations were acquired from inshore/intertidal dugongs that were
foraging in the intertidal zone than from animals in the subtidal zone. This telemetric artefact provided an indication of when the
animals were moving across shallow intertidal waters. More locations were received at night when the animals were generally closest
to the shore and in shallow water and fewer locations were received during the day when animals were further subtidal in deeper
waters. Hence, the average depth of water experienced by dugongs and their distances from the shore may have been significantly
underestimated, especially when fix success was low, since animals that were in shallower water were more likely to be sampled.
Consequently, my estimates of the diel patterns of dugong space use were more conservative than the actual situation and probably
underestimated the strength of the tidal patterns.
Dugongs were in deeper water more often during the morning than during late afternoon/night. There was no effect of tide
height on the actual depths in which dugongs occurred. Dugongs in coastal habitats were furthest from the shore between 6:00am and
12:00pm and closest between 3:00pm and 12:00am. Dugongs were closer to the shore during high tide than during low tide. Physical
environment variables had little or no effect on the spatial patterns of dugongs tracked in deep water. The movement speeds of the
coastal and deepwater dugongs increased marginally between 9:00am and 3:00pm, from an average of 200 to 300 m/hr.
Seven dugongs were GPS tracked at a fine spatial scale (< 10m) within the Burrum seagrass habitat in winter. Resource
selection within the habitat was modelled by comparing the dugongs' use of space with the distribution of their seagrass food
resources within an area defined using the combined space-use of the tracked animals. The association of dugongs with seagrass
quantity (biomass) and quality (nutrients) was analysed within six time/tide combinations to examine the influences of tidal
periodicity and the diel cycle on resource selection. I used resource utilisation functions (RUFs) to relate a probabilistic measure of
each individual dugong's space-use in each time/tide combination in a utilisation distribution (UD) (dependent variable) to the spatial
landscapes of the resource variables (independent variables) using multiple regression.
The RUF models indicated that dugong space-use was consistently centred over seagrass patches with high nitrogen
concentrations, except during the day at low tides when their space-use was centred over high seagrass biomass and away from
seagrass with high starch concentration. Dugong association with seagrass high in starch was positive during both day and night high
tides when dugongs could access intertidal areas where the seagrass biomass was generally low. Patterns of association with seagrass
species were less definite. Estimates of the intensity of dugong space-use in relation to available seagrass resources may be
confounded by the differentiation of fix probability by depth and speed. Because my estimates of dugong space-use in relation to
subtidal seagrass may have been more conservative than the data suggested, the positive association of dugongs with patches of high
biomass seagrass and avoidance of patches containing H. spinulosa and Z. capricorni in the subtidal zone may have been over-
estimated by this sampling bias.
I posit that dugong habitat selection and resource use occur hierarchically, across (at least) three different domains of scale:
(1)at a regional-scale (> 10 000 km2) dugongs select habitat at the level of individual bays along the Queensland coast; (2) at a
landscape-scale (< 10 000 km2), dugongs select seagrass pastures within bays along the Queensland coast comprised of nutritious
plant species; (3) at a local-scale (< 10 km2) within seagrass pastures that are within bays along the Queensland coast, dugongs select
seagrass patches on the basis of their nutrient concentrations. I recommend that the appropriate scales at which to manage dugong
populations and their seagrass habitats be co-ordinated within and across the hierarchical scales of habitat use indicated by my
analysis.
My finding that dugongs frequently undertake large-scale moves has implications for management at a range of scales, and
strengthens the aerial survey and genetic evidence for management and monitoring at ecological scales that cross jurisdictions. The
capacity of large-scale monitoring programs to detect trends in dugong numbers at scales of even thousands of km2 is confounded by
the dugongs' tendency to undertake large-scale moves. With movement between bays a common occurrence, estimates of population
size and trends can only be meaningfully made at regional scales.
The tendency for dugongs to track the bottom on large-scale movements may increase their vulnerability to incidental capture
in bottom set gill nets. In addition, if dugongs transfer their spatial knowledge of the location of quality food resource patches to their
offspring, then local depletions will lead to loss of this knowledge. Areas of high quality seagrass may thus become unknown to
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October 2007
dugongs. In the absence of grazing pressure such areas may become less valuable as dugong habitat if the early seral stage species of
seagrass preferred by dugongs convert to more fibrous species.
My research suggests that dugongs actively select seagrass habitats comprised primarily of H. ovalis and H. uninervis, based
on the high starch and nitrogen content of these species. Bays containing these quality food resources comprise an interlinked network
of core habitats between which dugongs frequently move. Accordingly, bays along the Queensland coast with seagrass meadows
dominated by H. ovalis and H. uninervis should be afforded a high level of protection as potential quality dugong habitat. Bays with
extensive intertidal meadows of H. uninervis should also receive enhanced protection, even if the seagrass biomass is low. Even
though they have low seagrass biomass, thermoregulatory habitats play an important role in maintaining dugong populations and
should be included in dugong habitat protection strategies.
CONFLICT TO CO-MANAGEMENT: EATING OUR WORDS TOWARDS SOCIALLY JUST CONSERVATION OF
GREEN TURTLES AND DUGONGS IN THE GREAT BARRIER REEF, AUSTRALIA
PhD Thesis Submitted by Melissa Nursey-Bray
ABSTRACT
Indigenous communities worldwide face multiple challenges to maintain their unique cultural identity and value systems. In
the natural resource management arena, these challenges include the imposition of western solutions to environmental management
and biodiversity protection. This imposition has caused the dispossession or relocation of Indigenous peoples from their lands, a loss
of traditional ecological knowledge, social disempowerment and economic inequity.
Indigenous peoples are responding to these challenges by asserting their cultural identity, developing cultural re-vitalisation
programs, and actively participating in western political processes for ongoing involvement in the environmental and natural resource
management domain. Nonetheless, to date, many of these programs are faltering or have failed in their long-term implementation.
Using a case study approach, my thesis examines this issue through an examination of Indigenous hunting of threatened
species in a protected area. My research is based on the contention that language matters, as it is an enabling tool which reveals the
knowledge and power relations in natural resource management. To this end, I compare perspectives held by Indigenous people on the
one hand and government Management Agencies on the other, about traditional hunting, planning and the management of Green
turtles (Chelonia mydas) and Dugongs (Dugon dugon) in Australia's Great Barrier Reef World Heritage Area (GBRWHA). To
compare these perspectives I used a combination of discourse analysis, historical analysis and participant observation to analyse the
development, implementation and subsequent failure of the Hope Vale Turtle and Dugong Hunting Management Plan, 'Guugu
Yimmithirr Bama Wii: Ngawiya and Girrbithi'.
My research yielded four key findings: (i) that significant differences exist between Management Agencies and Hope Vale
Community about hunting, planning and management (Management Agency discourse for example prioritised biodiversity protection,
while Indigenous discourse was primarily about ensuring cultural survival); (ii) that language in resource management does matter
because different linguistic interpretations within such programs have a direct impact on their efficacy (iii) that social justice
dimensions must be incorporated within management regimes in order to achieve both cultural survival and biodiversity protection
objectives; and (iv) that resource management initiatives can never be divorced from the impact of external events, actors and power
regimes.
I thus confirm my thesis or argument that the use and understandings of language in resource management reflect power and
knowledge relations, which in turn influence and impact upon the effectiveness of natural resource management programs.
Through the integration of these findings my thesis concludes with the presentation of a socially just conservation
methodology to guide future collaborations between Indigenous peoples and Management Agencies when addressing the ongoing
cultural harvest of wildlife (such as Green turtles and Dugongs) in protected areas.
LONG-DISTANCE OCEANIC MOVEMENT OF A SOLITARY DUGONG (Dugong dugon) to the COCOS (KEELING)
ISLANDS.
Hobbs, J-P.A.*, A.J. Frisch, J. Hender, and J.J. Gilligan. 2007. Aquatic Mammals 33(2):175-178. *Australian Research Council
Centre of Excellence for Coral Reef Studies, and School of Marine and Tropical Biology, James Cook University, Townsville,
Queensland, 4811, Australia; E-mail: Jean-Paul.Hobbs@jcu.edu.au
In this paper, we report on the arrival of a small (2 m long) male dugong (Dugong dugon) to the Cocos (Keeling) Islands (120
12' S, 960 54' E), Indian Ocean. The dugong arrived in June 2002 after traveling more than 1,000 km across deep open ocean, during
which time it would have been vulnerable to predation and presumably unable to feed. This is the longest recorded dugong movement
and demonstrates that dugongs have the capacity to make long-distance oceanic movements to colonise distant, unoccupied locations.
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October 2007
The solitary dugong has remained at the Cocos Islands for at least four years and exhibits unusual habitat use and behaviour; it
frequently occupies deep water on the edge of the coral reef and interacts with SCUBA divers.
RECENT LITERATURE
Adulyanukosol, K., S. Thongsukdee, T. Hara, N. Arai, and M. Tsuchiya. 2007. Observations of dugong
reproductive behavior in Trang Province, Thailand: Further evidence of intraspecific variation in dugong
behavior. Marine Biology 151(5):1887-1891.
Chapla, M.E., D.P. Nowacek, S.A. Rommel, and V.M. Sadler. 2007. CT scans and 3D reconstructions of
Florida manatee (Trichechus manatus latirostris) heads and ear bones. Hearing Research 228(1-2): 123-135.
Clementz, M.T., P.L. Koch, and C.A. Beck. 2007. Diet induced differences in carbon isotope fractionation
between sirenians and terrestrial ungulates. Marine Biology 151(5): 1773-1784.
De Iongh, H.H., and D. Bal. 2007. As we see it: harmonization of Red Lists in Europe: some lessons learned
in the Netherlands when applying the new IUCN Red List Categories and Criteria version 3.1. Endangered
Species Research 3:53-60.
Domning, D. P., J. Thomason, and D. G. Corbett. 2007. Steller's sea cow in the Aleutian Islands. Marine
Mammal Science 23(4):976-983.
De Iongh, H.H., W. Kiswara, W. Kustiawan, and P.E. Loth. 2007. A review of research on the interactions
between dugongs (Dugong dugon Muller 1776) and intertidal seagrass beds in Indonesia. Hydrobiologia
591:73-83.
Edwards, H.H., K.H. Pollock, B.B. Ackerman, J.E. Reynolds III and J.A. Powell. 2007. Estimation of
detection probability in manatee aerial surveys at a winter aggregation site. Journal of Wildlife Management
71(6):2052-2060.
Gur, B.M. and C. Niezrecki. 2007. Autocorrelation based denoising of manatee vocalizations using the
undecimated discrete wavelet transform. The Journal of the Acoustical Society ofAmerica 122(1): 188.
Harino, H., M. Ohji, G. Wattayakorn, K. Adulyanukosol, T. Arai, and N. Miyazaki. 2007. Concentrations of
organotin compounds in tissues and organs of dugongs from Thai coastal waters. Archives of Environmental
Contamination and Toxicology 53(3):495-502.
Hodgson, A.J., H. Marsh, S. Delean, and L. Marcus. 2007. Is attempting to change marine mammal behaviour
a generic solution to the bycatch problem? A dugong case study. Animal Conservation 10(2):263-273.
Kojeszewski, T. and F. E. Fish. 2007. Swimming kinematics of the Florida manatee (Trichechus manatus
latirostris): Hydrodynamic analysis of an undulatory mammalian swimmer. Journal of Experimental Biology.
210(14):2411-2418.
Marshall, C.D., S.D. Vaughn, D.K. Sarko, and R.L. Reep. 2007. Topographical Organization of the Facial
Motor Nucleus in Florida Manatees (Trichechus manatus latirostris). Brain, Behaviour and Evolution 70(3):
164-173.
girenews No. 48
October 2007
Miksis-Olds, J.L., P.L. Donaghay, J.H. Miller, P.L. Tyack, and J.A. Nystuen. 2007. Noise level correlates with
manatee use of foraging habitats. Journal of the Acoustical Society of America 121(5):3011-3020.
Morris, J.K., S.K. Jacobson, and R.O. Flamm. 2007. Lessons from an evaluation of a boater outreach program
for manatee protection. Environmental Management 40(4):596-602.
Muanke, P.B. and C. Niezrecki. 2007. Manatee position estimation by passive acoustic localization. Journal
of the Acoustical Society ofAmerica. 121(4):2049-2059.
Sarko, D.K., R.L. Reep, J.E. Mazurkiewicz, and F.L. Rice. 2007. Adaptations in the structure and innervation
of follicle-sinus complexes to an aquatic environment as seen in the Florida manatee (Trichechus manatus
latirostris). Journal of Comparative Neurology 504(3):217-237.
Sarko, D.K., J.I. Johnson, R.C. Switzer III, W.I. Welker, and R.L. Reep. 2007. Somatosensory nuclei of the
manatee brainstem and thalamus. Anatomical Record. Advances in Integrative Anatomy and Evolutionary
Biology 290(9):1138-1165.
Sorbi, S. and S.C. Vaiani. 2007. New sirenian record from lower pliocene sediments of Tuscany (Italy).
Rivista Italiana di Paleontologia e Stratigrafia 113(2):299-3 04.
Walsh, C.J., J.E Stuckey, H. Cox, B. Smith, C. Funke, J. Stott, C. Colle, J. Gaspard, and C.A. Manire. 2007.
Production of nitric oxide by peripheral blood mononuclear cells from the Florida manatee, Trichechus manatus
latirostris. Veterinary Immunology and Immunopathology 118(3-4): 199-209.
Wirsing, A.J., M.R. Heithaus, and L.M. Dill. 2007. Living on the edge: dugongs prefer to forage in
microhabitats that allow escape from rather than avoidance of predators. Animal Behaviour 74(1): 93-101.
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October 2007
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