Delineating yellowfin sole (Limanda aspera) reproduction in the northern Bering Sea provides information across the eastern Bering Sea continental shelf

Abstract

Yellowfin sole (Limanda aspera) is an abundant, commercially harvested flatfish that ranges across the northern and southeastern Bering Sea continental shelf. In recent years, the summer bottom trawl survey of the southeastern Bering Sea (SEBS) conducted by the National Marine Fisheries Service’s Alaska Fisheries Science Center (AFSC) extended into the northern Bering Sea (NBS) in August. This opportunity allowed for describing yellowfin sole reproductive parameters in the NBS, such as female length and age at maturation, reproductive status, and sex ratio distribution. Estimates of 50% female sexual maturity were 10.11 years (A50; 95% CI: 9.47–10.76 years; n = 209) and 28.47 cm (L50; 95% CI: 27.16–29.68 cm; n = 212). Histology indicated much of the mature population was approaching the end of spawning. Yellowfin sole spawning timing (summer) appears to be synchronous across the NBS and SEBS. There is evidence that part of the yellowfin sole spawning population in the NBS is connected to a recognized spawning migratory group from the SEBS. A higher proportion of females than males was observed, which varied by year and stratum. This was negatively related to warmer bottom temperature and positively related to location (western longitudes and northern latitudes). Yellowfin sole females in the NBS exhibit a similar size and age of maturation, depth of spawning, and sex ratio proportions with those females inhabiting the SEBS. These results provide further information for fisheries managers on the yellowfin sole stock throughout this region. Spatial and temporal aspects of reproduction, however, should be more thoroughly investigated.