Northeast Pacific resident-type killer whales ( Orcinus orca ) are known to form stable associations based on kinship between maternal relatives (matrilines) with a system of vocal dialects thought to reflect kinship relationships. We analyzed association patterns and acoustic similarity to study the social organization of killer whales in Avacha Gulf (Kamchatka, Russia), in the Northwest Pacific. The resident-type killer whales of Avacha Gulf formed temporally stable units that included maternal relatives with no dispersal observed. Acoustically, the killer whale community of Avacha Gulf was characterized by a system of dialects comparable to the communities of Northeast Pacific resident-type killer whales. Different units rarely associated with each other and these associations were nonrandom. Associations at different spatial levels did not always coincide with each other and with the patterns of acoustic similarity. Associations between units could change quickly irrespective of kinship relationships. The vocal dialect of a unit, which is more stable than the association patterns between units, might better reflect the overall kinship relationships. The stability and frequency of associations between units depended on the number of mature males in a unit, which could contribute to differences in the speed of change in vocal dialects and association patterns.

From 1999-2006, a long-term study of killer whales (Orcinus orca) off eastern Kamchatka has conducted photoidentification and acoustic studies from a field station in Avacha Gulf. From 2002-2005, wide-area large ship surveys have expanded the study to other regions in the Russian Far East (RFE) including: northeast Kamchatka, Commander Islands, Chukotka, Kuril Islands and northeast Sakhalin. In this paper we mainly discuss the killer whale status on the eastern coast of Kamchatka, and give a brief review of available information regarding the killer whale status in other areas of the RFE. During the field seasons 2005-2006, a total of 434 individuals were identified in Avacha Gulf in at least three acoustic clans with different dialects. Most are resident-type fish-eating whales. Some transient-type marine mammal eating whales have also been recorded in Avacha Gulf and in other areas of the RFE. Transients as well as some residents show bites from the cookie cutter shark (Isistius brasiliensis) which may indicate long distance travel along the Asian coast or out to sea. To date, live captures have removed at least two subadult females from the Avacha Gulf residents. A live-capture quota of 6-10 killer whales in the RFE has been granted every year since 2002 (8 for 2007) although data remain inadequate to support this. The conflict between whales and fishermen in the Sea of Okhotsk due to killer whale depredation merits further study.

Killer whales, Orcinus orca, were studied in Avacha Gulf, southeast Kamchatka, in the Russian Far East (RFE) from 1999-2003 using land- and boat-based photo-identification and sound recordings. A total of 121 photographically identified killer whales in the area have been determined to be residents based on (1) site fidelity with frequent re-sightings, (2) observations of predation on fish and (3) the recording of stable, resident-type dialects. The study has also documented transient-type marine mammal hunting killer whales in the RFE through morphological observations and biopsy documentation of contaminant levels and genetic characteristics. On 26 September 2003, some 32-37 resident-type killer whales were captured by the Utrish Dolphinarium Ltd, six of which had been photo-identified in previous years. One young female drowned in the nets; another young female was removed and sent to the Utrish Dolphinarium where she subsequently died. No more captures should be permitted until more is known about the population structure and population sizes of RFE killer whales.