UGA Shellfish Laboratory
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Marine resource management and conservation is critical to maintain currently productive fisheries. In this respect, applied research projects conducted at the laboratory have provided the basic biological information required by the Georgia Department of Natural Resources for rewriting the regulations governing and ensuring the future existence of the wild-stock shellfish industry in the state.
An important molluscan fishery in Georgia until recent years, it was mainly a winter trawl fishery. Landings in the past few years are reported to have declined to levels making it currently uneconomical. This cyclical pattern of exploitation and recovery is typical of whelk fisheries worldwide. Studies have been completed by MAREX to develop trawling gear that reduces turtle captures. Gear has also been tested to evaluate the potential of developing a pot based fishery, similar to whelk fisheries in the northeast. We are currently examining the Georgia whelk population structure (species, size) in both the offshore and intertidal environment. Eighteen months of trawled samples from a commercially harvested area have been processed and the population data is being analyzed. The reproductive cycle has been elucidated through gonadal indices based on reproductive organ weights expressed as a percentage of the eviscerated weight, and also through a histological analysis of the male’s seminal vesicle, which stores spermatozoa prior to copulation. The reproductive cycle will be confirmed through a histological analysis of the gonads. Egg capsule morphometrics and the diets of hatchling whelks have been documented Power, A.J., Covington, E., Recicar, T., & Eller, N., 2002. Observations on the egg capsules and hatchlings of the knobbed whelk, Busycon carica in coastal Georgia. Journal of Shellfish Research 21:769-776. Data analysis of our intertidal component, a massive mark and recapture effort involving the tagging of thousands of specimens is also underway. This study will document growth, intertidal population structure, and movement patterns. Research into genetic parentage with our research associates, Dr. John Avise, and Dr. DeEtte Walker from the UGA Genetics Department has identified a sex associated microsatellite marker which has been used to refute the theory that these whelks are sequential protandrous hermaphrodites Avise, J.C., Power, A.J. & Walker, D. Genetic sex determination, gender identification and pseudohermaphroditism in the knobbed whelk, Busycon carica (Mollusca: Melongenidae). Proceedings of the Royal Society of London, Series B, 271: 641-646 and Walker, D., Power, A.J. & Avise J.C. Sex linked markers facilitate genetic parentage analysis in knobbed whelk broods. J. Heredity 96(2): 1-6. A manuscript documenting the micro-spatial and temporal arrangements of genetic paternity along egg-strings of the knobbed whelk is currently being reviewed for publication in Molecular Ecology Walker, D., Power, A.J., Sweeney-Reeves, M. and Avise, J.C. Multiple Paternity and an “Almost-Smooth-Gravy” Model for Female Sperm Usage along Egg-Case Strings of the Knobbed Whelk, Busycon carica (Mollusca; Melongenidae). It is hoped that the fundamental life history information generated by these studies will assist the Georgia Department of Natural Resources develop a sustainable management plan for one of our most economically important shellfish species.
Georgia Whelk Landings
Intertidal Whelk Population Poster ppt (pdf)
Knobbed Whelk Life History Poster ppt (pdf)
Whelk Fishery Brochure