Contrasting Maturation and Growth of Northern Rock Sole in the Eastern Bering Sea and Gulf of Alaska for the Purpose of Stock Management

Abstract

AbstractThe primary purpose of this study was to provide commercial fishery managers with the age‐ and length‐at‐maturity information about northern rock sole Lepidopsetta polyxystra needed for them to set a sustainable overfishing limit and evaluate the precision of the two predictors of maturity. The estimated length at which 50% of eastern Bering Sea female northern rock sole matured (L 50) was 309 mm, which was significantly smaller than that for Gulf of Alaska females. We determined that the differences in L 50 between populations were probably the result of differences in the rate of female growth. Growth was significantly faster in the Gulf of Alaska than in the eastern Bering Sea during 1996 and 1999. However, by 2007 the growth rates were similar between these areas. The variability in growth was correlated with seawater temperature. There were also differences in the age at which 50% of the females matured (A 50) between the populations in the eastern Bering Sea (9 years) and the Gulf of Alaska (7 years). In contrast, within the eastern Bering Sea, females maintained a similar A 50 over several years, which indicates that age is the most reliable predictor of maturity for northern rock sole.Received April 8, 2011; accepted August 11, 2011