Some issues of walleye pollock reproduction in the pacific waters adjacent to the Kamchatka peninsula and the northern Kuril Islands in 2013–2022.

Abstract

Purpose: To characterize some issues of East Kamchatka pollock reproduction in the last 10 years.Methods: complex (ichthyoplankton and hydrological) surveys in the Pacific waters adjacent to the Kamchatka Peninsula and the northern Kuril Islands, surveys in the spawning center —  the “North” canyon, located in Avacha Bay, layer-by-layer surveys in the canyons and on the shelf.Novelty: the currently available data on the main spawning areas of the Eastern Kamchatka pollock were supplemented, new data on the state of the spawning stock, vertical distribution of eggs at different stages of development were presented.Results: During the period under consideration, the main pollock spawning in Avacha and Kronotsky bays occurred above deep-water canyons, and on the shelf near southeastern Kamchatka and northern Kuril Islands —  in the whole surveyed water area, in some years —  to the south of the island Paramushir. According to the results of ichthyoplankton surveys, model calculations, the spawning stock of the Eastern Kamchatka pollock peaked in 2010, and then it gradually decreased. Currently, resources are at an average level. Horizons of the main pollock spawning in deep-water canyons change in an inter-a nnual aspect. In addition, as egg development, as a result of internal processes occurring in the canyons (internal waves), it, then rises, then falls in the underlying layers of water.Practical significance: The results of the work can be used to improve the method of assessment of the current and prospective state of stocks, justification of the TAC of the Eastern Kamchatka pollock.