A RESIDENT POPULATION OF INDO-PACIFIC BOTTLENOSE DOLPHINS (TURSIOPS ADUNCUS) IN AMAKUSA, WESTERN KYUSHU, JAPAN |
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Authors: | Miki Shirakihara Kunio Shirakihara Jyunji Tomonaga Megumi Takatsuki |
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Institution: | Faculty of Bioresources, Mie University 1515 Kamihama, Tsu 514-8507, Japan E-mail:;Faculty of Fisheries, Nagasaki University 1-14 Bunkyo, Nagasaki 852-8521, Japan;Faculty of Bioresources, Mie University 1515 Kamihama, Tsu 514-8507, Japan |
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Abstract: | Residency patterns and population size were examined for Indo-Pacific bottlenose dolphins ( Tursiops aduncus ) in the coastal waters of Amakusa-Shimoshima Island, western Kyushu, Japan, from summer 1994 to fall 1998. A total of 203 individuals were identified. The number of newly identified individuals barely increased after the first 1.5 yr. The identified individuals in one season were frequently resighted with percentages of mostly over 60% during the subsequent seasons. Most of the dolphins off Amakusa were yearround residents, although the total range of their habitat was unknown. The population size estimated by the mark-recapture technique was 218 individuals with a CV of 5.41% in 1995–1997. The group commonly consisted of more than 100 individuals. The large group size was thought to be a response to feeding on schooling fishes. |
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Keywords: | Tursiops aduncus photo-identification mark-recapture technique year-round residency population size estimation group size Amakusa Japan |
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