Population growth and redistribution of reproductive burden between spotted seal rookeries in Peter the Great Bay

The author analyzes the accounting results of spotted seal offspring number in the local population from the Peter the Great Bay (Sea of Japan). The annual growth in the number of spotted seal pups on reproductive rookeries of the Rimsky-Korsakov archipelago islands exceeds 1,000 individuals. On some islands, the density of mature seals during the breeding season has reached a biological optimum, and the offspring number has stabilized. It is observed a steady increase in the pups number on the Bolshoi Pelis and Stenin islands, later integrating in the population reproduction. The reproductive burden on these islands increases from year to year. A general increase in the seal population number for the last quarter of the century has led to the formation of new reproductive rookeries of spotted seals both in Peter the Great Bay and beyond. The study results can be used as a basis for the population long-term monitoring, contributing to its conservation as anthropogenic impact on seals and their habitat ncreases.