Dynamics of the age composition of the red king crab males in the Barents Sea

Abstract

The aim of the work was to develop an algorithm for analysis and to elucidate the trends in the dynamics of the age composition of red king crab males in different areas of the Barents Sea.Materials were the data of research surveys and fisheries monitoring obtained in 2001–2022, as well as published results of long-term observations on juveniles and tagging.As results, an original algorithm which makes it possible to determine the age composition of the catches of red king crab males is suggested. The mean carapace widths of individuals of age 4+ — 11+ are 78, 99, 121, 142, 164, 185, 207, 228 mm respectively. The combination of the Hiat linear growth model with assumption of the normal distribution of size frequencies in the age class made it possible to give an adequate description of the dynamics of the age composition of king crab males in the Barents Sea. In each area to the west and east of 36 ° E. the number of noticeable generations exceeds that obtained from the size composition data. Noticeable generations appear with different annual frequency, and one can find different generations in different areas in the same years. It is suggested that 3 spatially isolated local populations inhabit in the (1) Varanger-Fjord, (2) in the area between the Motovsky and the Teribersky bays, (3) off the coastal area to the east of 36°E. If the generation of the age 5+ consider as recruitment, it seems that noticeable recruitment in the Varanger Fjord is formed in the closed bays of its southwestern part. The recruitment in the second region, is also formed in closed bays. In the third local population, recruitment is currently formed in the open areas of the shelf, while the coastal areas are gradually turning into eviction zone of the large males.Practical value. The obtained results can improve the efficiency of management of the red king crab stock in the Barents Sea and adjacent waters.