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Sirenian Conservation

Issues and Strategies in Developing Countries

Ellen Hines

Publication Year: 2012

This important scientific volume comprehensively explores the biology and ecological status of manatees and dugongs in all of the geographic regions where they can be found today, from the Caribbean to Eastern Africa, from Arabia to the Amazon, and from Japan through the South Pacific to Australia.

Many of these dwindling populations are situated in developing countries--locales that have previously received little attention in the scientific literature.

In these areas, people occupying rivers or coastlines still capture sirenians for food and other uses (oil, bones for carving, leather). In addition, disruption, erosion, or complete loss of sirenian habitat occurs because of dredge and fill, coastal run-off, chemical pollution, and damage from boat propellers.

Sirenian Conservation features contributions from an international group of scientists who are working to address the many challenges to manatee and dugong food supply, environment, reproduction, and survival. They share stories of programs that rescue, rehabilitate, release, and monitor these animals; offer reports on practical, replicable, and cost-effective management techniques; and summarize current research strategies.

Published by: University Press of Florida


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pp. vii-viii

List of Illustrations

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pp. ix-x

List of Tables

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pp. xi-xii

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pp. xiii-xiv

When I started studying dugongs in the early 1970s, much sirenian research was limited to the study of the natural history of animals that were dead or in captivity and in the United States or Australia. There are obvious limitations to each of the dimensions of this approach, and this book is testament to the modern, global, cross-disciplinary approaches ...

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pp. 1-3

In October of 2003 I sent an e-mail to the sirenian scientific community to gauge interest in an edited volume on manatees and dugongs specifically in developing countries. This book as I envisioned it would emphasize conservation and management issues, research strategies, and the role of scientists in integrating their research into conservation. ...

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1. The Role of Sirenians in Aquatic Ecosystems

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pp. 4-11

The role of sirenians in aquatic ecosystems is largely a function of their feeding ecology. Sirenians are large herbivorous aquatic mammals that often congregate and, being mammals, have high energetic requirements relative to other marine herbivores. An adult dugong can weigh from 250 to 600 kg1, ...

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2. Vulnerability of Sirenians

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pp. 12-20

Sirenians represent one of the three living orders of mammals that include marine representatives. The other marine mammals are included in the Order Carnivora (walruses, seals, sea lions, sea and marine otters, and polar bears) and the Order Cetacea (whales, dolphins, and porpoises). ...

Section I: Regional Issues in Sirenian Conservation

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3. Florida Manatee Status and Conservation Issues: A Primer

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pp. 23-35

Manatees make headlines and television news stories on a regular basis in Florida, whether it involves the rescue of an orphan or injured animal from a backyard canal or impassioned protests at public hearings regarding proposed speed zones. The public’s fascination with this charismatic aquatic mammal generates strong support for its conservation and protection. ...

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4. West Indian Manatees (Trichechus manatus) in the Wider Caribbean Region

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pp. 36-46

The Antillean or Caribbean subspecies (Trichechus manatus) of the West Indian manatee is classified as endangered on the IUCN Red List because the current population is thought to be fewer than 2,500 mature individuals and is predicted to undergo a decline of more than 20% over the next two generations unless effective conservation actions are taken1. ...

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5. The Amazonian Manatee

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pp. 47-53

Among the sirenians, the Amazonian manatee (Trichechus inunguis) is the only endemic species in the Amazon Basin and the only sirenian restricted to freshwater systems. Indigenous groups living in areas where the Amazonian manatee occurs have their own names for the species ...

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6. The West African Manatee

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pp. 54-57

The West African manatee (Trichechus senegalensis) is a slow-moving, herbivorous aquatic mammal found in shallow coastal waters, rivers, estuaries, and lagoons. Until fairly recently the West African manatee was among the “forgotten” marine mammals, the sirenian about which the least was known. ...

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7. Dugongs in Asia

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pp. 58-76

Since World War II, increased exploitation of primary resources has been the policy of many Asian countries1. Especially since the 1960s, there have been high birth rates and accelerated population growth in coastal areas. The population in Asia grows by 22.5% every ten years, with 60 to 70% of people living within 50 km of the coast. ...

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8. Dugongs in Japan

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pp. 77-83

The dugongs of Japan are in dire straits. Many thought they had already been extirpated when, in the 1990s after plans for a U.S. military base threatened seagrass beds in Henoko Bay, an investigation confirmed the continuing presence of dugongs around Okinawa Island. There are critical obstructions to dugong and seagrass research in Japan. ...

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9. Eastern African Dugongs

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pp. 84-90

The eastern coast of Africa marks the westernmost boundary of the dugongs’ global range. They are known to occur in the waters off Somalia, Kenya, Tanzania, and Mozambique (map 9.1). Their range also extends farther east off the islands of the Seychelles, Comoros, Mayotte, and Madagascar1. ...

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10. Dugongs in Arabia

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pp. 91-98

In the Arabian region dugongs occur in the Red Sea and the Arabian (Persian) Gulf (map 10.1). They are known locally by a variety of names: bugarah al bahr (cow of the sea: Bahrain, Qatar, and UAE); arus al bahr (bride of the sea: Gulf and central Red Sea coasts of Saudi Arabia, and Bahrain); taweelah (southern Red Sea coasts of Saudi Arabia and Yemen); ...

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11. Dugongs in Australia and the Pacific

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pp. 99-106

In the Pacific region, dugongs occur in the coastal waters of Australia, New Caledonia, Palau, Papua New Guinea, the Solomon Islands, and Vanuatu, with occasional sightings in Guam and Yap1 (map 11.1). This region presents a diverse array of cultures, social and government systems, conservation and threat abatement approaches, and biological habitats ...

Section II: Research Strategies for Sirenians

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12. Using Interviews in Sirenian Research

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pp. 109-115

A crucial step in any research on endangered species is to obtain baseline information about their geographic range, present population status, and relevant conservation issues. As sirenians are routinely found in coastal, riverine, and lagoon systems, they are often in such close proximity to human settlements that their lives and behavior are significantly affected by human activities. ...

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13. Tagging and Movement of Sirenians

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pp. 116-125

Sirenians occur in waters that range from crystal clear to chocolate-milk brown. They can live anywhere from inland small channels covered with overhanging vegetation to offshore marine waters. They may spend several months in one location or make long migrations or movements at a relatively fast pace of 20 to 50 km per day. ...

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14. Techniques for Determining the Food Habits of Sirenians

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pp. 126-132

Sirenians, the only fully aquatic mammalian herbivores, are efficient hindgut-digesters1, with a broadly diverse diet. Diet determination can be accomplished by various techniques, but here we offer three methods that can be employed with minimal effort and nominal expense. ...

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15. Individual Identification of Sirenians

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pp. 133-138

The ability to identify an individual in a population of outwardly identical sirenians is often an important aspect of population research. Identification and monitoring of individuals can provide insights into questions of reproductive success, longevity, intraspecific social behaviors, determination of seasonal site fidelity, ...

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16. Health Assessment of Captive and Wild-Caught West Indian Manatees (Trichechus manatus)

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pp. 139-147

As human populations increase along coastlines and waterways, their various activities impact the health of sirenians in these fragile environments. Medically examining these animals in their natural habitats and gauging how both individual and overall population health alter as the environment changes serves as a tool ...

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17. Sirenian Pathology and Mortality Assessment

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pp. 148-156

Previous chapters in this book have discussed how rapid technological development in recent history has accelerated human impact on sirenians. Determining the causes of the numerous threats to manatees, especially those that result in mortality or disease (tables 17.1 and 17.2) will enable implementation of appropriate protection measures. ...

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18. Delineating and Assessing Habitats for Sirenians

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pp. 157-167

Habitat has been defined as the physiographic conditions and resources (e.g., shelter, food, water, temperature) present in an area that allow the occupancy, survival, and reproduction of a given organism1. The physiographic conditions and resources of a habitat delimit the distribution and abundance of the various organisms within it. ...

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19. Sirenian Genetics and Demography

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pp. 168-178

As previous chapters in this book make clear, the longterm survival of the four extant species of Sirenia is in peril due to many confounding factors, the majority of which are caused, directly or indirectly, by human activity. One of the most critical effects, along with habitat fragmentation and a reduction in manatee and dugong numbers, is a possible loss of genetic diversity. ...

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20. Boat- and Land-Based Surveys for Sirenians

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pp. 179-185

Observers taking part in boat and land-based surveys of cetaceans and sirenians scan and collect data from a particular vantage point. They study the distribution, abundance, behavior, feeding ecology, and migration of a wide variety of species, including dolphins1, sperm whales2 and dugongs3. ...

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21. Utility and Design of Aerial Surveys for Sirenians

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pp. 186-195

Aerial surveys have been used as a tool to assess aspects of sirenian biology for three decades. Although aerial surveys can be a useful method of assessing sirenian population distribution and abundance, they can be logistically difficult and expensive and may not always be the appropriate method. ...

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22. Organic Contaminants and Sirenians

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pp. 196-203

Most programs that have assessed the status of marine mammals have used two primary approaches: counting individuals or estimating population size, and documenting mortality. A more complete approach1 involves at least two additional factors: health of individuals and populations, and demography of the population. ...

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23. Manatee Rescue, Rehabilitation, and Release Efforts as a Tool for Species Conservation

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pp. 204-218

Wildlife rehabilitation programs have been used on numerous species to augment conservation and management efforts. The rescue, rehabilitation, and release of injured or sick animals have become a widespread practice among wildlife management programs1. These programs can make a significant contribution, especially to threatened and endangered species ...

Section III: Strategies for Conservation-Oriented Science

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24. Working with Communities for Sirenian Conservation

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pp. 221-227

If manatees and dugongs are to survive, people living in communities where sirenian populations still thrive need to be involved in protecting them. However, among these communities are some of the poorest and most marginalized members of society. And some have traditional, exploitive links to sirenians: ...

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25. Guidelines for Developing Protected Areas for Sirenians

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pp. 228-234

The range of sirenians spans almost 90 subtropical and tropical countries and territories on five continents. Most of these countries are classified as less developed. The purpose of this chapter is to assist managers and scientists with their responsibilities in these countries to work with stakeholders to design protected areas that will reverse the declines in sirenian populations. ...

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26. The Role of Law in Protecting Sirenians and Their Habitat in Developing Nations

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pp. 235-242

As seen throughout this book, challenges to sirenian conservation are formidable and complex. Unfortunately, legal regimes have not kept pace with the increasing need to conserve and protect marine ecosystems. Since developing nations have within their jurisdiction over 90% of the coastal waters that lie within international 200-nautical-mile exclusive economic zones (EEZs), ...

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27. The Role of Scientists in Sirenian Conservation in Developing Countries

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pp. 243-245

Based on the increasing impact of humans on a species’ habitat and that species’ small and/or decreasing population, at a certain point in scientific research, a project has to shift its priorities from biological assessment to conservation. While research to establish baseline information about a species is rarely complete, ...

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28. A Framework for Sirenian Conservation in Developing Countries

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pp. 246-254

Sirenians are in danger of extinction because of factors common not only to other marine mammals but to endangered species worldwide: habitat degradation and destruction, and directed or incidental killing. Specific circumstances may change, but the results are the same. ...


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pp. 255-272


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pp. 273-312

List of Contributors

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pp. 313-318


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pp. 319-326

E-ISBN-13: 9780813042701
Print-ISBN-13: 9780813037615

Page Count: 348
Publication Year: 2012