Publication Date

Fall 2011

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Moss Landing Marine Laboratories

Advisor

Gregor M. Cailliet

Keywords

Age, Chondrichthyans, Growth, Habitat, Rajidae, Reproduction

Subject Areas

Biology

Abstract

The order Rajiformes, or skates, is a morphologically conservative group that exhibits a wide range of life history characteristics. This inter-species variability warrants species-specific research. This study investigates the age, growth, reproduction, and habitat of the Starry Skate, Raja stellulata, which is endemic to the U.S. West Coast. Age and growth parameters were determined using two preparation techniques: gross sectioning and histological sectioning. The assumption that gross sections deposit one band pair a year was indirectly validated with centrum edge analysis and marginal increment ratio. It was not indirectly validated with histological sections. Age estimates from gross sections ranged from 0 to 11 years, and growth was best described by the two parameter von Bertalanffy growth function in which L∞ = 865 mm TL and k = 0.15. Age estimates from histological sections ranged from 0 to 15 years, and growth was best described by the Gompertz function in which L∞ = 845 mm TL, g = 0.15, and k = 1.53. Histological section results are recommended for describing growth of R. stellulata because the longevity is more conservative. Raja stellulata exhibits year-round reproduction and attains 50% maturity at 632 mm TL, and 11.2 years old for females and 603 mm TL, and 11.5 years for males. Raja stellulata was collected most often on hard substrate between 70 and 150 m depth. An age/depth trend within the central California skate assemblage was found where increased habitat depth correlated with increased longevity.

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