Report of the 1995/96 Japanese Whale Research Programme Under Special Permit in the Antarctic (JARPA) in Area IV and eastern part of Area III

The ninth survey of the Japanese Whale Research Programme Under Special Permit in the Antarctic (JARPA) was carried out in the Antarctic Area IV (south of 60° S between 70°E and 130°E) and eastern part of Area In (south of 60° S between 35°E and 70°E). The survey was conducted for 118 days, from 26 November 1995 to 22 March 1996. The research fleet was composed of a research base vessel, engaged in the biological survey of minke whale sampled, three sighting /sampling vessels (SSVs) engaged in sighting and sampling and one sighting vessel (SV) dedicated exclusively to sighting activities. Survey in the eastern part of Area III was conducted before and after the survey in the entire Area IV. The survey in Area IV was conducted during the period in which the peak migration of minke whales was expected. Survey in the eastern part of Area III was conducted as a feasibility study on stock identity, and samples were taken during an early and late period of the feeding season in order to study intra-seasonal changes. During the sampling, one animal was taken randomly from schools sighted as primary sighting. This was made in order to improve the representation of the population. Dwarf form minke whales were not sampled. The SV was exclusively engaged in whale sighting survey in all the research areas, along an independent sighting track line. Sighting and sampling activities were independently conducted by the three SSVs, in parallel track lines to each other. Searching distance for these four vessels was of 21,455.5 n.miles. During the research period, 893 schools (2,021 animals) of the ordinary minke whale were sighted as primary sighting and 244 schools (564 animals) as secondary sightings. Out of 693 schools (1,439 animals) primarily sighted by the SSVs, 440 ordinary form minke whales (273 males and 167 females) were randomly sampled. The distribution pattern of minke whales in Area IV was not considerably different from that observed during the 1993/94 JARPA. In the previous research, high density was observed in the Prydz Bay. However, such high density was not found in the present research. Distribution of cetacean species during the research period suggest the segregations between minke and humpback whales, and between sperm and beaked whales including southern bottlenose whales. Those were related to the pattern of the ice edge in the research area. It is supposed that concentration of pregnant female in the Prydz bay lead to such difference, because no significant different is observed when the data of the Prydz bay is excluded from the western part of the Area IV. The eastern part of the Area III located closely to the Prydz bay and many large matured female were collected in eastern south of the Area III in the second survey. It seems that the most of female minke whale in the Prydz bay tend to migrate through in the eastern part of the Area Ill. During the survey, 3 schools (4 animals) of the blue, 25 schools (48 to 50 animals) of the humpback whale and 4 schools (4 animals) of the right whale were photographed for natural markings. Ten skin biopsy samples were taken from humpback whales and one sample was taken from the blue and right whales, respectively.