Scientists note a decrease in the number of sea otters in Kamchatka

The press service of the Kronotsky Reserve reported on the results of the first expedition in several decades to study sea otters off the southeastern coast of Kamchatka. Field work in June 2022 was carried out by employees of the Kronotsky Reserve and the Kamchatka branch of the Pacific Institute of Geography, Far Eastern Branch of the Russian Academy of Sciences.

Two sea otter populations are distinguished in the Kamchatka region. Commander inhabits the waters of the Commander Islands. The Kamchatka-Kuril population lives in the coastal waters of the northern Kuril Islands, eastern Kamchatka from Cape Lopatka to Cape Kamchatsky and a small area of ​​the western coast.

Regular monitoring of the Commander sea otter population has been carried out over the past 50 years, so the demographic processes occurring in it are well known. From 1992 to 2005, the birth rate was high enough to ensure a steady increase in the number of these animals. However, according to research in 2019, only 1,683 individuals were counted. Thus, the population has decreased by more than 70%.

Monitoring of the Kamchatka population of sea otters has not been carried out over the past 20 years. Scientists have data that in 2000 in the southern part of Kamchatka there were up to 8000 sea otters. But, given the decline in the number of animals throughout the range, during an expedition along the southeastern coast of the peninsula in June 2022, the fears of biologists were confirmed.
The number of sea otters in this area now goes not to thousands, but to hundreds of individuals. In the course of the research, all encountered groups of sea otters and single individuals were taken into account, the number of animals in the group, the number of females with cubs, and the distance from the shore at the locations of the groups were determined. The total number of sea otters on the survey route was 1089 individuals, including 99 females with pups.

The largest concentrations of sea otters were found much further north than in the years of previous studies. The reasons for their redistribution and movement in a northerly direction are not yet clear. Perhaps this is due to the depletion of food resources.

Now scientists expect that scientific expeditions in the waters of Kamchatka will become annual.

In addition, specialists expect to expand the zone of accounting work and cover the northern Kuril Islands, as well as the south of the western coast of Kamchatka. This will make it possible to survey the entire Kamchatka-Kuril sea otter population.

"It is necessary to continue regular monitoring, assess the state of the food supply of this endemic species in the Kamchatka waters and determine the limiting factors that prevent the growth of the number of animals," the press service quotes the words of Evgenia Volkova, a researcher at the Kronotsky Reserve.

According to scientists, the number of sea otters can also be affected by tourist disturbance, the development of shipping, water pollution, entanglement in nets, disease, poaching and predation by killer whales. All this remains to be elucidated in the course of future long-term studies.

The northern sea otter is an animal from the weasel family. It is endemic to the North Pacific. Along with the platypus and common otter, this species has the thickest fur in the world. It was because of this that in the 19th century the species was practically exterminated off the coast of Kamchatka. Near the coast of the Kronotsky Reserve, sea otters appeared only in the 1970s after almost a century of interruption.

The species is included in the List of the International Union for Conservation of Nature (IUCN) and the Red Book of Russia.