Preliminary investigation of photomanipulation in Atlantic cod (Gadus morhua) broodstock

Proper broodstock management is critical to the successful aquaculture of a species. Photomanipulation of spawning is a technique used to create multiple spawning events per year instead of the usual single spawning. Atlantic cod (Gadus morhua) are being developed for aquaculture as an alternative finfish species in Newfoundland with great emphasis being placed on broodstock management. We placed Atlantic cod broodstock on a photoperiod regime to promote spawning 3 months in advance of the normal spawning season of April-May. Photomanipulation began in June 2001 and the first manipulated spawning was observed on January 31, 2002. Egg quality and survival were excellent based on the measured parameters of fertilization, cell division abnormalities, and percent survival to hatch. Forty five litres of high-quality eggs were produced in forty one batches. Abnormalities in cell divisions averaged 4.5%. This confirms that Atlantic cod broodstock respond well to photomanipulation and will contribute to improved management and commercialization of this species.