Eight reproductively isolated populations have been described from the extensive spotted seal's range. Of these, the population from the Peter the Great Bay (Sea of Japan) is the only one that lost its ecological relationship to ice. Seals of this population breed on island shores. Based on the analysis of published data, this review summarizes information about the main features of the biology and ecology of the spotted seal population in the Peter the Great Bay that distinguish it from other populations. Over the last 25 years, the size of this population has increased three to four-fold. This happened despite the poor condition of the species in some parts of the range. The most serious threats to this population are accidental entanglement and death of seals in fishing gear and habitat pollution by toxic substances. The prospects for survival of the population in current conditions are evaluated. The spotted seal population in the Peter the Great Bay is extremely important for the conservation of the genetic diversity, which increases the chances to survive for the species in general. The breeding grounds of spotted seals in the Peter the Great Bay are protected by the Far Eastern Marine Biosphere Reserve.

Published online 25 September, 2024; Print publication 31 October, 2024