Study of Contingency between the Spatial Distributions of Gray Whales and Their Feeding Objects Offshore North-East Coast of Sakhalin Islandтезисы доклада
Дата последнего поиска статьи во внешних источниках: 27 января 2016 г.
Аннотация:The subject of this research is the gray whale Eschrichtius robustus that inhabits the
northern parts of the Pacific Ocean. The gray whale of the Okhotsk-Korean (or
Western) population is classified as critically endangered according to ISEP criteria;
current estimate of the total population numbers is approximately 150 specimens.
The main feeding area where western gray whales spend their summer-fall period,
constitutes a narrow (with depths no greater than 50 m) sea area that runs alongside
the coastline over approximately 100 km, and is located in the north-eastern part of
the Sakhalin Island. Unlike other cetaceans, the gray whale feed on benthos – the
primary components of their ration are bottom-dwelling crustaceans belonging to
the groups of Amphipoda and Isopoda. Systematic research into the western gray
whale, initiated by a group of oil companies working offshore Sakhalin, has been
going on since 1997. We analyzed the contingency between the spatial distributions
of the western gray whales and the biomass of the benthic organisms serving as their
food source over the period of 2002-2012. The analysis was conducted using GIS
technologies. Cartographic alignment of whale occurrence distribution and the
abundance of food benthos demonstrate the high degree of their spatial contingency,
thus indicating the important role of the food factor in the formation of the whale
spatial distribution. Maximum values of cumulative yearly estimates of sighted gray
whales are associated with the areas with the maximum density of benthos. The
analysis of the contingency dynamics carried out with an account of the specifics of
forage benthos distribution shows that most attractive for whales are shallow vast
fields with high and relatively evenly distributed Amphipoda biomass.