[1] The island consisting of sedimentary and clastic rocks from Late Cretaceous is gradually degrading due to erosion, precipitation and aggressive organic matter from sea birds.

[7] Current island vegetation is rather scarce and consists of crustose lichens, mosses and seaside ragwort (Senecio pseudoarnica).

[1][9] Tyuleny Island is known as the source of arboviruses isolated from Ixodes uriae ticks that are abundant in the local seabird colony.

Japanese maps from the late 19th century contain the Ainu place name: アトヤモシリ (Atoyamoshiri — ‘the island of net fishing’).

[13] There are several other Ainu names for this place mentioned in various sources, having other meanings and spelled differently, such as ‘the island of adult fur seals’.

Although later commercial harvest was officially limited by quotas, pelts were still taken illegally, pushing the fur seal population to the brink of extinction.

[3] Fur seals were gathered by driving them from their haul-out area to a killing spot (fenced yard-field) where they were held in a large pod.

Several seals were then cut from this large pod and driven to a group of several men who stun the animals by hitting them on the skull or upper neck with a solid wooden club.

[16] This led to the seizure of several schooners by Russian men-of-war in 1884 and 1891, including the arrest of a party of seventeen men left by a British vessel in 1895.

[19] Since the late 19th century, various structures were established on the island, including houses for hunters and military personnel, small factories for fur seal skinning and salting pelts, as well as a fenced yard-field for killing.

[3] Currently there are fences separating the guillemots’ and fur seals’ breeding plots as well as territory for scientists, including wildlife observation towers and old Soviet buildings.

They demolished the fences separating the territories of birds and pinnipeds, leading to fur seals trampling thousands of guillemot eggs.

Young fur seals and sea lions play with scraps of fishing nets, plastic straps, and other gear that entangles around their necks and cannot be removed.

As the neck continues to grow, especially in males, the collar becomes critically tight, causing deep, unhealing wounds, often resulting in death.