Until 2003, the Japanese Sea Lion was considered to be a relative of the California sea lion. Marine biologists categorized the genus as Zalophus californianus japonicus. However, reclassification became inevitable, under the dictates of taxonomist debates on the distant habitation preferences, differences in morphology, DNA, and behavior patterns exhibited by the wollebaeki, japonicus, and californianus sub-species. The Japanese Sea Lion inhabited the coastal areas of the Japanese Archipelago, along the Sea of Japan, and the Korean Peninsula.
These sea lions primarily inhabited both sides of the Pacific Ocean, and were a common sight even along the Kuril Islands, right up to the southernmost tip of the Kamchatka Peninsula. There are a number of places around the region that still bear witness to the magnificence of this sea lion through their names. The coast line of Japan has places such as Asahikawa, which translates to 'sea lion rock', and Inubosaki point or the 'dog-barking point'. The latter gets its name from the distinct dog-bark-like howl associated with the Japanese sea lion.
The species thrived on the open and flat, sandy beaches and rocky coves, whenever the need arose. The typical male weighed more than 550 kg, and reached a length of around 2.5 meters. It was dark gray in color and visibly larger than their Californian counterparts. The females grew to a length of around 1.6 meters, and flaunted a visibly lighter shade of gray or brown, than the males. These mammals were fondly referred to as 'black sea lions', even though they were not melanistic or high in melanin concentration.
They were extensively hunted for their meat and blubber or fat. The blubber was a much sort after source of fat and oil. The oil extracted from the organs and skin of this species was also used as an important ingredient in oriental medicine. Its whiskers made good pipe cleaners, while the skin generated bags and apparel. Commercial harvesting of the Japanese sea lion also resulted in the mammal being sought for circus antics.
Research reveals that more than 3,000 Japanese sea lions were harvested at the turn of the 20th century. Overfishing brought the numbers down to a few dozens by the 1930s, but commercial harvesting only ceased when the species became extinct in the 1940s. Marine biologists also blame the submarine warfare during World War II for the destruction of their natural habitat. Records reveal that the last of the mammals were sighted by Korean coast guards in the 1950s.
Maine biologists are still investigating a number of cryptid sightings on record, all through the 1960s and 1970s. In 1974, the last juvenile was captured off the coast of Rebun Island, Hokkaido. Today, stuffed specimens can be observed at the National Museum of Natural History, Leiden, The British Museum and various museums across the Japanese Archipelago. In 1990, the species was pronounced 'extinct' on the IUCN Red List of Endangered Species.
The numerous efforts made to reintroduce sea lions to the Sea of Japan include those made by:
- The South Korean Ministry of Environment
- The National Institute of Environmental Research
- The 2007 joint research venture between China, North and South Korea and Russia
The South Korean Ministry of Environment is currently funding research and support for the revival of sea lions along the coast of Japan. The extinction of the mammal has affected the associated symbolism in Japan, making restoration of the species a national concern. The pelt and skull specimens continue to intrigue visitors at these exhibitions, and question our responsibility towards the survival of the ecosystem.