The Marine Finfish Reproduction and Broodstock Development program at the Fisheries and Oceans Biological Station in St. Andrews, NB has provided a leading contribution to the developing commercial halibut culture industry in Atlantic Canada. Using wild-caught halibut broodstock, maintained under two photo thermal regimes to manipulate reproductive cycles, eggs were provided to industry partners on a consistent basis from 1996-1999. Since 1999, industry members have obtained independent wild-caught broodstocks, but large volumes of high-quality eggs remain limiting in the effort to produce juveniles. The current project focuses on three possible methods of improving egg quality in halibut. In addition, excess eggs produced at SABS will be made available for commercial use by the industry partners involved in the project.
Atlantic halibut are serial batch spawners that release mature oocytes at intervals into the ovarian lumen to complete final oocyte maturation (FOM) and egg hydration. As with other marine batch spawners, the timing of egg stripping with respect to the timing of ovulation can significantly impact egg yield, fertilization rate, and hatching rate. An objective method for determining the correct timing of egg stripping is needed in order to allow a consistent supply of high quality eggs. The purpose of this study is to determine if the pH, osmolality, or refractive index of the ovarian fluid can be used to predict when ovulation will occur, and therefore provide a more accurate assessment of when to strip eggs. In addition the efficacy of GnRH implants to regulate ovulation in Atlantic halibut will be ascertained.
This is an excellent opportunity for industry to get the benefits of egg production from the first mature cultured halibut females (93 year class) in North America held at SABS. The quality of eggs from F1 cultured fish will be compared to wild-caught captive broodstock. The ultimate goal of the egg quality research in this project is to increase the production capacity of the halibut industry in Atlantic Canada.
Reid, D.P., Smith, C.-A., Rommens, M., Blanchard, B., Martin-Robichaud, D., and Reith, M.A. 2007. Genetic Linkage Map of Atlantic Halibut. Genetics 177: 1193-1205.