Marine Mammals

Abstract

The coasts of the East Sea (Japan Sea) of the Korean Peninsula are known to have been populated by whales since prehistoric times. This association has lasted throughout the history of Korea's dynasties without interruption. Traces indicating the presence of whales are written in petroglyphs and in the histories of the dynasties. From the late 19th century, many foreign whaling ships started entering Korean waters, especially in the East Sea. After Japan won the Russo-Japanese War, monopoly whaling by the Japanese funded by their capital lasted until 1945. At that time, statistical data on whaling in the East Sea was first recorded. According to those records, the major species of whales were fin whales and the minke whales, with gray whales, humpback whales and others. Koreans introduced Japanese-style whaling ships and started whaling in postcolonial times. Commercial whaling in Korea continued actively, focused mainly on minke whales, until the International Whaling Commission declared a moratorium on commercial whaling in 1986. According to whaling data, bycatches and stranding, the baleen whales observed in the East Sea are northern right whales, blue whales, fin whales, sei whales, Bryde's whales, minke whales, humpback whales, and gray whales. Thus far, the minke whale has been the dominant species. For toothed whales, there are large species such as sperm whales, Baird's beaked whales, and Stejneger's beaked whales, which are discovered once or twice every year through bycatches or stranding. Small and medium-sized species are extremely diverse, including killer whales, Pacific white-sided dolphins, Risso's dolphins, harbor porpoises, and common dolphins. The most commonly observed species are common dolphins and Pacific white-sided dolphins. In the case of common dolphins, about a hundred of them are bycaught or stranded every year along the coast of the East Sea. These species are distributed throughout the year in the East Sea, but Dall's porpoises and harbor porpoises show changes in latitudinal distributions depending on seasonal changes. Pinnipeds living in the East Sea are the Steller sea lion, the northern fur seal and the spotted seal. Most of them live in the northern East Sea and a few migrate to the south coast of the Korean Peninsula. The Japanese sea lion was once abundant in the East Sea, but it is now extinct.