ИСТИНА |
Войти в систему Регистрация |
|
Интеллектуальная Система Тематического Исследования НАукометрических данных |
||
Most populations of large whales declined dramatically due to commercial whaling in the 20th century. Through the mid- to late 20th century encounters with most baleen whale species in the western Pacific were extremely rare. The first signs of population recovery appeared in the beginning of the 21st century. Here we compare the results of surveys performed along the eastern Kamchatka coast in 2002 and in 2015. We found a significant increase in the number of sightings of humpback whales. In 2002, a few humpbacks were observed only in Olutorsky and Karaginsky gulfs. In 2015, we found several large feeding aggregations of humpback whales in Karaginsky Gulf, and some solitary whales and pairs occurred in Ozernoy, Kamchatsky and Avacha gulfs. The occurrence of fin whales also increased: only one pair was sighted off Kronotsky Peninsula in 2002, but in 2015 encounters with fin whales were regular in all surveyed areas. The occurrence of other whale species did not change significantly between these periods. In 2015, we encountered several Baird's beaked whale groups in Kamchatsky and Ozernoy gulfs; this species was not registered in 2002, but it may have been missed because its distribution is limited to specific areas with steep slopes. The occurrence of killer whales, grey whales, minke whales and Dall's porpoises was similar in 2002 and 2015. Our results suggest that the populations of humpback whales and fin whales in the western Pacific may be increasing locally after the decades of commercial whaling.