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Killer whale status and live-captures in the waters of the Russian Far Eastстатья
- Авторы: Filatova O.A., Shpak O.V., Ivkovich T.V., Borisova E.A., Burdin A.M., Hoyt E.
- Сборник: IWC Scientific Committee
- Серия: SC/65b/SM07
- Год издания: 2014
- Аннотация: Killer whale ecology and population structure have been studied in detail in the eastern North Pacific, but much less information is available from the western North Pacific, where live-capturing have started in recent years. In this paper we summarize the current information about killer whales and the live-capture procedures in the western North Pacific. We have described two killer whale ecotypes in the Russian Far East: fish-eating and mammal-eating ecotypes similar to resident and transient killer whales found in the Northeastern Pacific. Resident killer whales were encountered much more frequently than transients off eastern Kamchatka, near the Commander Islands and Kuril Islands. Transient killer whales prevailed in the western and northern Okhotsk Sea and off Sakhalin Island. Mitochondrial control region haplotypes were different for resident and transient killer whales. Genetic analysis of microsatellite DNA showed that resident and transient killer whales belong to reproductively isolated populations. Values of stable isotope δ15N were significantly higher in transients, indicating their higher trophic level. Using the photo-identification method, we have identified 688 resident killer whales in Avacha Gulf, Kamchatka, and more than 800 around the Commander Islands. Some mixing occurs between Avacha Gulf, Commander Islands and the other regions of eastern Kamchatka, but the extent of the mixing varies. We also identified 26 transient killer whales in Avacha Gulf and 18 transient killer whales near the Commander Islands. Recapture rate of transient killer whales in that area was low. In the western Okhotsk Sea no dedicated study has been conducted. We identified 55 transient killer whales through the opportunistic studies. There were multiple resightings within and between seasons in the same area and in adjacent areas. Only transient killer whales have been observed so far in this region. During the period of 2002-2011, six killer whales were captured in different areas of the Russian Far East. In 2012-2013, seven killer whales were captured in the western Okhotsk Sea: one young female in 2012, and six whales of unknown sex and age in 2013. The live-capture of killer whales raises concerns because it targets the same local stock of transient killer whales in the western Okhotsk Sea. Russian officials deny the existence of killer whale ecotypes in the Russian Far East, and consequently do not manage fish-eating and mammal-eating killer whales as different management units. No reliable abundance estimates of either killer whale ecotype in the Okhotsk Sea is available.
- Добавил в систему: Филатова Ольга Александровна