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- Life history of Bathyraja trachura from the eastern Bering Sea, with evidence of latitudinal variation in a deep-sea skate species
- Although many skates possess life history characteristics that may make them vulnerable to exploitation, the detailed biological information needed to enact effective management schemes is lacking for most species. The objectives of this study were to provide age, growth, and maturity estimates for the roughtail skate, Bathyraja trachura, from the eastern Bering Sea. Maximum age was estimated at 36 yr based on band pair counts in vertebral centra. Of the four growth models applied, the logistic model provided the best description of growth (asymptotic total length = 911 mm; growth coefficient = 0.131 yr-1). There was no evidence of difference in growth between males and females. Females attained maturity at larger sizes and older ages than males. The median size-at-maturity was estimated at 741 mm total length (TL) for males and 796 mm TL for females; median age-at-maturity was estimated at 21.1 yr and 24.7 yr for males and females, respectively. The results of this study may indicate a latitudinal pattern in size and growth, with individuals from the eastern Bering Sea growing more slowly and reaching higher maximum ages than previously reported for specimens collected off the western coast of the continental United States. Copyright © Marine Biological Association of the United Kingdom 2013., Fish and Fisheries, Downloaded from: http://journals.cambridge.org/action/displayFulltext?type=1&fid=9155760&jid=MBI&volumeId=94&issueId=02&aid=9155757 (9 June 2014).
- Winton, Natanson, Kneebone, Cailliet, Ebert
- A comparison of age and growth of the Bering skate, Bathyraja interrupta (Gill and Townsend, 1897), from two Alaskan large marine ecosystems,
- The Bering skate, Bathyraja interrupta, is commonly found in both the Bering Sea and Gulf of Alaska, where skates are a regular bycatch in commercial long line and bottom trawl fisheries. This is the first study to examine the age and growth of B. interrupta, and one of the few studies to directly compare growth parameters of a skate species between management regions. Ages were estimated based on band counts using the standard gross-sectioning method of vertebral centra preparation. Additionally, a preliminary investigation was conducted into the utility of the histological method. Several growth models were compared and the best-fit model for both regions was identified as the logistic model using the Akaike's Information Criterion approach. No significant difference was detected between sexes for any model in either region; however, a slight but significant difference was found between regions. The parameters of the logistic growth model based on the gross-sectioned preparation were L∞=82.80cm TL and k-1yr=0.23 for the eastern Bering Sea and L∞=86.94cm TL and k-1yr=0.20 for the Gulf of Alaska. Age estimates from the gross sectioned vertebral centra provided a minimum longevity of 19 years and 21 years, respectively. Estimates based on the histologically prepared samples provide overall slightly higher age estimates, but the same maximum age of 21 years. © 2014 Elsevier B.V., , ,
- Ainsley, Ebert, Natanson, Cailliet