analyses of gonadal cycling by oyster broodstock, crassostrea virginica (gmelin), in louisiana

J.E. Supan, Ch.A. Wilson-2001

Journal of Shellfish Research, 20(1): 215-220

Abstract:

Oysters held near-shore in Caminada Bay, Louisiana during the summer, exhibit hypertrophic gonads with prominent genital canals beneath transparent mantle tissue about four weeks post-hatchery spawning, indicating recycling. Broodstock (N=200) were analysed histologically over a two-year period to document such gametogenesis, using Gonad/Body Ratios (GBR) and developmental stages. Ten oysters were randomly selected from a broodstock pool prior to each spawning attempt, and monthly during the winter-spring. As expected, the mean GBR before successful spawning attempts was significantly greater (p</= 0.05) than the mean GBR before unsuccessful attempts. A dramatic drop in the percent occurrence of the advanced spawning and regression stage from May to June, a >40% spawning stage occurrence from May to October, and fluctuations in the percent occurrence of early and late developmental stages during the summer months illustrates gonadal recycling.

(Office of Sea Grant Development, Louisiana State University, Baton Rouge, Louisiana 70803, USA)

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