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Japanese Sea Lion, Zalophus japonicas

The Japanese sea lion (Zalophus japonicas) is in extinct species that could once be found in the Sea of Japan. The biggest populations occurred around the Korean peninsula and the Japanese Archipelago. In these areas, both sea lions and seals have influenced the names of some coastal areas, like Inubosaki or “dog-barking point.” It was formally classified as a distinct species in 2003 due to a difference in behaviors and range, but was previously known as a subspecies of the California sea lion.

The Japanese sea lion reached an average body length between 7.5 and 8.2 feet with an average weight between 992 and 1,234 pounds. This species displayed sexual dimorphism, with females reaching an average body length of 5.2 feet. It was dark grey in color and preferred to rest in caves, rather than in the open. When breeding, this species chose open sandy shores instead of protective caves.

Before the Japanese sea lion became extinct, humans hunted it for many purposes, using its whiskers, skin, oil, and its organs. Its meat has been described as unappetizing and was only used to make oil for lamps. In the early 20th century, this species was captured and used in circuses. During the Jōmon period in Japan, bones of the Japanese sea lion were extracted from shell middens.

By researching early 1900’s fishing records, it was found that 3,200 Japanese sea lions were killed each year, but by 1915, over fishing caused a decrease in seal population numbers and only 300 were caught that year. By 1940, locals ceased hunting the Japanese sea lion because it was nearly extinct. By that year, 16,500 sea lions had been killed, leading experts to believe that the species their extinction had been caused by overhunting, although habitat destruction from World War II played a role. The last confirmed sighting of the Japanese sea lion occurred in 1974, when a juvenile was captured in northern Hokkaido off the coast of Rebun Island.

Conservation efforts have been initiated in more rent years. The South Korean Ministry of Environment searched for the seals in order to reintroduce them into their natural habitat, and the National Institute of Environmental Research of Korea evaluated the viability of the project. In 2007, it was announced that a project between North and South Korea, Russia, and China would be initiated to research the Japanese sea lion, although it is listed as extinct in the IUCN Red List. This plan would consist of experts searching Russian and Chinese waters in order to reintroduce them into Japanese waters. If this is not successful, California sea lions will be transported to South Korea. These efforts not only offer the possibility of restoring the Japanese sea lion population, but also bring national concern and ecotourism to the ecosystem of the area.

Image Caption: Japanese Sea Lion, stuffed specimen at Tennōji Zoo, Osaka, Japan. Credit: Nkensei/Wikipedia  (CC BY-SA 3.0)

Japanese Sea Lion Zalophus japonicas


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