A group of sea-animal researchers has launched a nonprofit organization to protect and preserve the marine ecosystem around the four islands off Hokkaido at the center of a territorial row between Japan and Russia.

The Wildlife Center of Japan aims to study the marine ecosystems around the Russian-held islands, known for their diverse marine life, and conduct ecological tours with sea-animal researchers in an effort to find a way for humans to coexist with the unique natural environment, group members said.

According to the members, the waters are home to many diverse plant and animal species, including sea otters, sea lions and tufted puffins, which are rarely seen in Hokkaido.

For example, the members have confirmed the existence of about 20,000 tufted puffins in the area, whereas only a dozen live in Hokkaido.

Around Etorofu, the members said, there are about 2,000 sea otters. The animals had been on the verge of extinction due to Japan's overexploitation of the species before the war.

Center member Mari Kobayashi said the waters around the islands of Kunashiri, Etorofu and Shikotan and the Habomai islets are the whole world's heritage, and preserving them will set a precedent for protecting Hokkaido's coastal marine ecosystem.

The new group is made up of 13 researchers who spent the past three years studying the marine animals and seabirds around the islands under a visa-free exchange program involving experts in various fields.

Visa-free exchange programs of this kind between Japan and Russia began in 1999.

The dispute over ownership of the islands, which were seized from Japan by Soviet forces at the end of World War II, has prevented Japan and Russia from concluding a postwar peace treaty.