Terrestrial and aquatic fauna
Kamchatka boasts diverse and abundant wildlife. This is due to climates ranging from temperate to subarctic, diverse topography and geography, many free-flowing rivers, proximity to highly productive waters from the northwestern Pacific Ocean and the Bering and Okhotsk Seas, and to the low human density and minimal development. Nonetheless, commercial exploitation of marine resources and a history of fur trapping has taken its toll on several species.
Among terrestrial mammals, Kamchatka is best known for the abundance and size of its brown bear populations. In the Kronotsky Nature Preserve there are estimated to be three to four individuals per 100 square kilometres. Other fauna of note include carnivores such as wolf, arctic and other fox, lynx, wolverine, sable, several species of weasel, ermine and river otter; several large ungulates, such as bighorn sheep, reindeer, and moose; and rodents/leporids, including hares, marmot, lemming and several species of squirrel.
The peninsula is the breeding ground for Steller's sea eagle, one of the largest eagle species, along with the golden eagle and gyr falcon.
Kamchatka contains probably the world's greatest diversity of salmonid fish, including all six species of anadromous Pacific salmon (chinook, chum, coho, seema, pink, and sockeye). Biologists estimate that a sixth to a quarter of all Pacific salmon originates in Kamchatka. Kuril Lake is recognized as the biggest spawning-ground for sockeye in Eurasia. In response to pressure from poaching and to worldwide decreases in salmon stocks, some 24,000 square kilometers (9,300 sq mi) along nine of the more productive salmon rivers are in the process of being set aside as a nature preserve.
Cetaceans that frequent the highly productive waters of the northwestern Pacific and the Okhotsk Sea include: orcas, Dall's and harbor porpoises, humpback whales, sperm whales and fin whales. Less frequently, grey whales (from the Eastern population), beaked whales and minke whales are encountered. Blue whale are known to feed in summer off of the southeastern shelf. Among pinnipeds, Steller's sea lions, northern fur seals, spotted seals and harbor seals are abundant along much of the peninsula. Further north, walruses and bearded seals can be encountered on the Pacific side, and ribbon seals reproduce on the ice of Karaginsky Bay. Sea otters are concentrated primarily on the southern end of the peninsula.
Seabirds include northern fulmars, thick and thin-billed murres, kittiwakes, tufted and horned puffins, red-faced, pelagic and other cormorants, and many other species.
Typical of the northern seas, the marine fauna is likewise rich. Of commercial importance are Kamchatka crab, scallop, squid, pollock, cod, herring, halibut and several species of flatfish.