“Hot Spots” of Submesoscale Dynamics and Their Comparison with Walleye Pollock Spawning Areas in the Pacific Waters off the Kamchatka Peninsula

Based on an analysis of Sentinel-1 radar images 2015–2024 covering the coastal waters off the Kamchatka Peninsula and the northern Kuril Islands, a database was compiled. The database contains 3895 manifestations of short-period internal waves and 1156 of submesoscale eddies. The analysis shows that these phenomena are a permanent and inherent components of the dynamics of regional coastal waters. The highest activity of both feature types was recorded during the summer season. Persistent areas of frequent occurrence (“hot spots”) were identified: Avacha and Kronotsky gulfs, the southeastern shelf of the Kamchatka Peninsula, and the area east of the Fourth Kuril Strait. A comparison with ichthyoplankton survey data (approximately 1500 stations for 2003–2024) reveals direct spatial overlap: areas of increased occurrence of submesoscale processes are largely confined to the main aggregation zones of walleye pollock eggs and larvae (Gadus chalcogrammus). This observed spatial correspondence suggests that submesoscale processes should be regarded as a previously unaccounted abiotic factor, warranting their inclusion in the assessment of ecological conditions for the reproduction of commercial resources in the region.