Of the rookery distribution differences in northern fur seals and Steller sea lions in the waters of the Russian far east

We investigated factors influencing differences in the rookery distribution patterns between northern fur seals and Steller sea lions in the waters of the Russian far east. The limited distribution of northern fur seal rookeries observed during 1991-2001 resulted from the need for shallow tide pools near the shore for pups to practice swimming. In addition, the large and concentrated populations of the seals required large flat areas and a high degree of natal site fidelity. In contrast, in the case of Steller sea lion rookeries observed along the Kuril islands in 2001, the pups were able to swim under maternal care, and their populations were smaller and had a lower degree of natal site fidelity. So, from our observations, their rookeries, unlike those of northern fur seals, are therefore widely distributed across diverse topographical conditions in the waters of Russian far east.