Report of the Second Workshop on The Biology and Conservation of ...

catch in fisheries should be addressed urgently,through research, monitoring, and management.2.2.2 Steno bredanensisDistributionNo new information.Population/stock structureNo new information.sampling should be attempted in areas where thisspecies is seen on a regular basis, such as <strong>the</strong>Babuyan Islands. There is a need for assessment<strong>of</strong> <strong>the</strong> effects <strong>of</strong> by-catch in longline fisheries,especially for waters between <strong>the</strong> Philippinesand Taiwan. In light <strong>of</strong> <strong>the</strong> paucity <strong>of</strong> specimenmaterial for <strong>the</strong> region, samples (skulls and genetictissues) should be collected whenever possible.2.2.3 Sousa chinensisPopulation statusNo new information.Habitat statusNo new information.Directed catchesSpecimens thought to have been harpooned havebeen found in Taiwan fishing ports (Doc. 6). Thespecimen from <strong>the</strong> Philippines mentioned in <strong>the</strong>1995 workshop report may have been taken in apurse seine. Stocks in SE Asia may be affected by<strong>the</strong> infrequent drive-fishery catches in Japanesewaters.By-catchesBy-catch occurs on longlines and in drift gillnetsin Taiwanese waters (Doc. 6). This specieshas a tendency to be associated with logs ando<strong>the</strong>r floating objects, and it may <strong>the</strong>refore bepredisposed to capture in longline and purse seinefisheries. In <strong>the</strong> Babuyan Islands, Philippines,some by-catch may occur on longlines. Twostranded specimens from Vietnam had evidence<strong>of</strong> gillnet markings, and were probably by-caught(Doc. 4).Needs for additional researchNo directed research on this species has beenconducted anywhere in SE Asia. Such studieswould be beneficial, especially in areas <strong>of</strong> highfishing effort in deep water. Opportunistic biopsyDistributionThe distribution <strong>of</strong> <strong>the</strong> Indo-Pacific humpbackdolphin is fragmented in many areas. Wang andHung reported that <strong>the</strong> distribution in Chinesewaters has recently been shown to extend to <strong>the</strong>west coast <strong>of</strong> <strong>the</strong> main island <strong>of</strong> Taiwan. Verifiablerecords from <strong>the</strong> coast <strong>of</strong> China suggest that eightor nine populations <strong>of</strong> humpback dolphins mayexist from <strong>the</strong> Vietnam border to <strong>the</strong> mouth <strong>of</strong> <strong>the</strong>Yangzi River, mostly centered around <strong>the</strong> mouths<strong>of</strong> large rivers (Jefferson 2000b). Humpbackdolphins appear to be common in <strong>the</strong> HonTre River area (Doc. 3). Dolar reported anunconfirmed stranding in <strong>the</strong> Turtle Islands area<strong>of</strong> <strong>the</strong> Philippines. [Editors’ note: <strong>the</strong> specimenhas now been confirmed to be an Indo-Pacifichumpback dolphin]. The species has now beenconfirmed from Cambodian waters (Doc. 34).Population/stock structureThe taxonomy <strong>of</strong> <strong>the</strong> genus Sousa remainsconfused in spite <strong>of</strong> considerable recent research(IWC in press). Although West African humpbackdolphins (Sousa teuszii) clearly constitute aseparate species, <strong>the</strong> taxonomy <strong>of</strong> animals in <strong>the</strong>Indo-Pacific must await <strong>the</strong> completion <strong>of</strong> ongoingstudies using molecular genetic and morphometrictechniques. Some preliminary evidence suggeststhat eastern (chinensis-type) and western IndianOcean (plumbea-type) forms may be distinct(Jefferson 2000c). At this point, though, it isprudent to provisionally recognize only one<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 69