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Abundance and Trends in Size <strong>of</strong> <strong>the</strong> Indo-Pacific Humpback DolphinPopulation in <strong>the</strong> Pearl River Estuary, P.R. ChinaJefferson, Thomas A. 1,2 ; Hung, Samuel K. 2 ; Qiu, Yong-Song 3(1) Southwest Fisheries Science Center, NOAA, NMFS, P.O. Box 271, La Jolla, CA 92038 USA(2) Hong Kong Cetacean Research Project, P.O. Box 28598, Gloucester Road Post Office,Wanchai, Hong Kong(3) South China Sea Fisheries Institute, CAFS, Guangzhou 510300, P.R. ChinaLine transect surveys using 12-15 m vessels have been conducted since late 1995 to estimate <strong>the</strong>abundance and population trends <strong>of</strong> Indo-Pacific humpback dolphins (Sousa chinensis) in HongKong and adjacent waters <strong>of</strong> China’s Pearl River Estuary (an area <strong>of</strong> 3,856 km2). Distributionpatterns, as well as data from photo-identification and molecular genetic studies, indicate thata single population inhabits this area. We used 43,376 km <strong>of</strong> sighting effort collected duringconditions <strong>of</strong> Beaufort 3 or lower, along with 1,673 on-effort sightings, to estimate abundance innine survey areas in which dolphins were sighted. All <strong>of</strong> <strong>the</strong> areas with dolphin sightings wereinfluenced to varying degrees by freshwater discharge from <strong>the</strong> Pearl River. Four o<strong>the</strong>r areasin Hong Kong’s eastern waters with little or no influence from <strong>the</strong> Pearl River had no dolphinsightings. There were seasonal fluctuations in <strong>the</strong> densities <strong>of</strong> dolphins in different areas. Thehighest total <strong>of</strong> <strong>the</strong> estimates for any one season was 1,383 dolphins in winter. This represents aminimum estimate <strong>of</strong> total population size. Mark-recapture analysis <strong>of</strong> photo-identification dataprovided an alternative population size estimate <strong>of</strong> 753 dolphins, but we believe that this is anunderestimate. We also examined trends in abundance in North Lantau. Line transect estimateswere made for 12 6-month periods, and <strong>the</strong> resulting pattern was for a decline from <strong>the</strong> start <strong>of</strong><strong>the</strong> study until summer/autumn 1998, and an increasing trend since <strong>the</strong>n. The apparent reversalin <strong>the</strong> trend occurred at about <strong>the</strong> time <strong>of</strong> <strong>the</strong> opening <strong>of</strong> Hong Kong’s new international airport.The trends analysis could suggest that <strong>the</strong> population is increasing, or at least stable, but <strong>the</strong>reis uncertainty due to <strong>the</strong> potential for animals to have moved into and out <strong>of</strong> <strong>the</strong> trends studyarea.<strong>Second</strong> <strong>Workshop</strong> on <strong>the</strong> Biology and Conservation <strong>of</strong> Small Cetaceans and Dugongs <strong>of</strong> SE Asia 143
Indonesia’s Cetacean Migration Corridors: Management Implications <strong>of</strong> Long-Term Visual and Acoustic Cetacean Surveys in Komodo National Park andAlor, Indonesia.Kahn, Benjamin 1 ; Pet, Jos 2 ; James-Kahn, Yvonne 3(1) Director, APEX Environmental, Indonesia Cetacean Program, PO Box 59 Clifton Beach - Cairns, 4879Qld, Australia; e-mail: bkahn@attglobal.net(2) Deputy Director, Coastal and Marine Program Indonesia, The Nature Conservancy, Coastal and MarineConservation Center, Jl. Pengembak 2, Sanur, Bali, Indonesia; e-mail: jpet@attglobal.net(3) ICP Program Manager, APEX Environmental, PO Box 59 Clifton Beach - Cairns4879 Qld, AustraliaIn <strong>the</strong> May 1999 – April 2001 survey periods a total <strong>of</strong> 18 cetacean species were identifiedduring 207 survey hours over 71 field days during five intermonsoon field seasons. The surveyscovered an estimated 4706 nautical miles. The species encountered were predominantly oceanicodontocetes, but also included a several balaenopterid species. An estimated total <strong>of</strong> 7082individual cetaceans were sighted during 299 encounters. Acoustic contact with cetaceans wasrecorded during 38.1% <strong>of</strong> <strong>the</strong> 217 listening stations. Temporal and spatial patterns are apparenton <strong>the</strong> species level. Major species-specific results include relative abundance indices, sitepreferences and calving rates. A regionally distinct baleen whale, <strong>the</strong> pygmy Bryde’s whaleBalaenoptera edeni, was positively identified with genetic pr<strong>of</strong>iling techniques. The Alor surveyswere initiated in 2001. Preliminary results indicate this region is one <strong>of</strong> <strong>the</strong> prime cetacean habitatsin Indonesia. Critical habitats, including regional migration corridors, have been identified.Major environmental impacts observed include reef bombing (acoustic habitat degradation) ando<strong>the</strong>r fisheries interactions. Cetacean watching potential has increased due to <strong>the</strong> survey results.However, this may not be an appropriate tourism activity without strict controls and enforcementin place first.Significant extensions to KNP’s legislative boundaries have been designed to include preferredhabitats <strong>of</strong> <strong>the</strong> Park’s cetaceans. These extensions are incorporated in <strong>the</strong> 25-year managementplan and will increase <strong>the</strong> protective status <strong>of</strong> cetaceans in KNP. The long-term surveys havealso shown that cetaceans should be an important component <strong>of</strong> resource management plans,conservation measures and alternative livelihood options for Marine Protected Areas in easternIndonesia.An Indonesian Whale Sanctuary will be crucial, as for migratory whales and dolphins <strong>the</strong>degrading forces on <strong>the</strong>ir ecology <strong>of</strong>ten occur outside <strong>the</strong> current areas <strong>of</strong> protection. Such asanctuary would complement <strong>the</strong> Indian Ocean Sanctuary and protect <strong>the</strong> tropical Indo-Pacificcetacean migration corridors.144 CMS Technical Series Publication Nº 9 - 2005
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CMS Technical Series Publication N
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Published by the U
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TABLE OF CONTENTSpage1. Preliminari
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AppendicesAppendix 1 - List <strong
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8 CMS Technical Series Publication
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10 CMS Technical Series Publication
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The cetacean species reviewed inclu
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Table 1. Major commercial Commonwea
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(2) State Legislation.In state wate
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(2) Identification of</stro
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Coastal speciesThe most frequently
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Coastal speciesThere are currently
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and Guangxi Provinces (Yang et al.
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Table 3. Records of</strong
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can be viewed as the</stron
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Workshop participa
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ioaccumulation have not yet been ex
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of fishermen who h
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are supplied to scholars and organi
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threats. Many marine mammal populat
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waters or recognize important inter
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James Cook University (Queensland,
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the last ten years
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proactive in engaging more staff an
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of SE Asia. Two sp
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San Francisco (Negros Oriental); Li
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Legal status and present management
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within 15 kilometers from t
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US, has actively participated in ce
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the project was su
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Recently, the camp
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Mekong River downstream of<
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porpoises in tropical waters <stron
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species in the Ind
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Population/stock structureNo new in
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Needs for additional researchStock
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waters of SE Asia,
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caused mortality is certainly large
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Needs for additional researchProper
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from SE Asia, it is known to occur
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3.1.7 AustraliaDugongs occur all al
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Table 8. Conservation objectives id
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3) Monitoring and assessment <stron
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Table 10. Outline of</stron
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Page 95 and 96: 6. SUMMARY AND CONCLUSIONSThe works
Page 97 and 98: 96 CMS Technical Series Publication
Page 99 and 100: Bank, E. 1931. A popular account <s
Page 101 and 102: Dalebout, M. L., J. G. Mead, C. Sco
Page 103 and 104: Jaaman, S. A., E. Tangon, I. Isnain
Page 105 and 106: Lin, Y.-J. 1997. Mitochondrial DNA
Page 107 and 108: Smith, B.D., T. A. Jefferson, D. Ho
Page 109 and 110: Yang, W.-C. 2000. Morbillivirus inf
Page 111 and 112: CHOU Lien-SiangDepartment o
Page 113 and 114: Brian D. SMITHWildlife Conservation
Page 115 and 116: APPENDIX 3Agenda1. Preliminaries2.
Page 117 and 118: Doc. 22 Dugong conservation activit
Page 119 and 120: AreaDatesSurveyTypeEffortSpeciesNo.
Page 125 and 126: Phase ofActionPlan
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Page 129 and 130: f) recognizing that by-catch in fis
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Page 133 and 134: APPENDIX 9Abstracts of</str
Page 135 and 136: The (IUCN Critically Endangered) Du
Page 137 and 138: Status of
Page 139 and 140: Cetacean Habitats in the</s
Page 141 and 142: Conservation of <s
Page 143: Summary of Current
Page 147 and 148: Conservation Effort to Protect <str
Page 149 and 150: The Status of <str
Page 151 and 152: Can the Developing
Page 153 and 154: Status and Conservation of<
Page 155 and 156: Legal Hunting of C
Page 157 and 158: Indo-Pacific Bottlenose Dolphins (T
Page 159 and 160: Feasibility Study of</stron
Page 161 and 162: Songs of a Humpbac
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