Atlantic halibut (
) are large fish, and hence practicality dictates that a relatively small number of adults will be retained for broodstock at any one hatchery, increasing the potential for inbreeding. Broodstock domestication is necessary for an economically productive and viable aquaculture industry within Atlantic Canada.
Parentage, genotypic and PIT tag information will be used to direct 2002 matings of mature 1996 F1 (first generation domestic broodstock) at two industry locations (Maritime Mariculture, Inc. and R&R Finfish Development, Inc.) and one Fisheries and Oceans location (Biological Station, St. Andrews, NB) to avoid inbreeding and prevent loss of genetic variation. We will also genotype wild broodstock and 1998 F1 at another industry partner (Scotian Halibut) to determine available levels of genetic variation and identify potential relatives in first generation domestic broodstock.
A medium density linkage map for Atlantic halibut will also be created. Using this linkage map we will be able to identify markers that control economically important traits (known as quantitative trait loci (QTL)) such as growth, survivability and metamorphosis. Selecting future broodstock based on genotypic information at QTL (known as marker assisted selection (MAS)), we can significantly improve those traits. In addition to QTL MAS, we will identify familial effects on economical traits. Genotyping will determine the effect of family or single parent has on growth rate and size at market. This information will also be incorporated into broodstock selection.
Finally we will study methods to cryopreserve Atlantic halibut milt. Currently the industry is limited to crossing only those broodstock, which spawn at similar times. By cryopreserving milt, directed spawning can be accommodated and the most ideal mating can be performed regardless of spawning times or location.
P, S. Pongsomboon, T. Jackson, C. McGowan, C. Murphy, D. Martin-Robichaud and M. Reith. 2005. Microsatellite analysis indicates an absence of population structure among
in the north-west Atlantic. J. Fish Biol. 67: 570-576.