Date

2009

Document Type

Master's Thesis

Degree Name

Master of Science (M.S.)

Department

Moss Landing Marine Laboratories

Abstract

The eastern Bering Sea is an area of high skate abundance and diversity. Relative to their abundance, however, little is known about basic life history traits for most skate species living there. Fisheries managers require life history information, including age, growth, and reproduction, to develop sustainable fisheries models. The two species in the current study are the Commander skate, Bathyraja lindbergi, and whiteblotched skate, Bathyraja maculata. Samples were collected during NOAA Fisheries survey cruises in the eastern Bering Sea and through the National Marine Fisheries Service Alaska Fisheries Science Center observer program. Age estimates from two vertebral preparation techniques, gross sectioning and histology, were compared. Histological preparation of vertebrae had greater levels of precision, consistently greater band pair counts, and produces significantly different growth parameters than gross sectioning. Therefore the results below are only from vertebrae prepared histologically. Maximum age estimates for B. lindbergi females is 33 years and for males is 31 years, for B. maculata females is 33 years and for males is 36 years. Caudal thorns were not useful ageing structures for these species. Age at 50% maturity for B. lindbergi females is 21.1 years and males is 21.9 years, for B. maculata females is 25.8 years and males is 24.5 years.

Comments

Thesis (M.S.) Division of Science and Environmental Policy. Moss Landing Marine Laboratories

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