Comparative age and growth of the Aleutian skate, Bathyraja aleutica, from the eastern Bering Sea and Gulf of Alaska

摘要

The Aleutian skate (Bathyraja aleutica) is a large deep-water species that commonly occurs in bycatch of Alaskan trawl and longline fisheries. Although prominent in the skate biomass of the eastern Bering Sea (EBS) and Gulf of Alaska (GOA) ecosystems, minimal biological information exists. To increase our understanding of this potentially vulnerable species, and address the possibility of two separate populations in Alaskan waters, the age and growth of B. aleutica was studied. Vertebral centra were examined for age determination, and multiple growth models were evaluated to determine growth characteristics. Skates from the EBS attained maximum ages of 17 and 16 years for females and males, respectively, and the two-parameter von Bertalanffy growth functions generated estimates of k = 0.13 yr.-1 and La = 162.1 cm for females, with similar results for males. Skates from the GOA reached 19 years in females and 18 years in males. Growth parameters of female skates from the GOA were estimated as k = 0.11 yr.-1 and La = 160.0 cm, whereas males grew faster, with estimates of k = 0.15 yr.-1 and La = 138.2 cm. The results of this study may indicate the presence of distinct populations of B. aleutica in the eastern North Pacific.