15 JUNE 1999
D.H. Moroney, R.L. Walker-1998
Journal of Shellfish Research, 17(4): 1085-1091
Abstract:
Our goal is to produce large, deep-cupped, single oysters, Crassostrea virginica, for the half-shell and steamer market. However, oysters in Georgia are small and grow in clusters because of high recruitment rates and lack of appropriate substrate upon which oyster spat can settle. It was hypothesized that oyster recruitment would be lower at sites farther back into a tidal creek presumably because of high tidal flushing rates (40% exchange per tide). To test this hypothesis, spat collectors were deployed monthly at 10 sites along two branches of House Creek, Little Tybee Island, Georgia from April to November, 1996. The total number of oysters on each collector was enumerated and 30 oysters per site were measured for shell length. Significant differences in recruitment rates were observed between sites (p<0.001). Generally, oyster spat recruitment was lowest at the most remote sites in a tidal creek and increased seaward. The recruitment rate at one site was higher than expected based on our hypothesis. However, the percent cover by adult oyster reefs at this site was also higher and may explain the higher recruitment rate. Therefore, our data support the hypothesis. Based upon the results of this study, the most remote sites in a tidal creek with relatively low percent cover by adult oyster reefs should exhibit low recruitment rates. It may therefore be possible to reduce oyster clustering by culturing oysters in these areas for grow-out to market size.
(Shellfish Aquaculture Laboratory, University of Georgia Marine Extension Service, 20 Ocean Science Circle, Savannah, Georgia 31411, USA)