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Newfoundland projects work toward cod commercialization

Presented by Canadian agencies and organizations currently undertaking aquaculture research in Canada - Commercialization of cod aquaculture in Atlantic Canada has taken a significant step forward with two research projects currently underway in Newfoundland.

Newfoundland projects work toward cod commercialization - Presented by Canadian agencies and organizations currently undertaking aquaculture research in Canada - Commercialization of cod aquaculture in Atlantic Canada has taken a significant step forward with two research projects currently underway in Newfoundland.

Under the direction of team leaders Dr. Joe Brown and Lynn Lush the Commercialization of Atlantic Cod and Strategies for Improved Hatchery Broodstock Management respectively, are working in tandem to ensure an environmentally and economically viable cod aquaculture industry will soon be up and running.

The Ocean Sciences Centre at Memorial University received funding from the Atlantic Canada Opportunities Agency to provide essential research to enhance the establishment of a commercial Atlantic cod aquaculture industry in Newfoundland and to assist in the continued development of the Atlantic halibut industry in Atlantic Canada. The research team works closely with a number of industry partners including Northern Cod Ventures Limited, Long Island Resources and the Newfoundland Aquaculture Industry Association.

Nearly three years into this project, the challenges addressed relate to larval production, weaning, cannibalism and juvenile growth. Also being investigated are stocking density, size of entry into sea cages, cage husbandry, early maturation, fish health and disease. Research on egg, larval and juvenile husbandry takes place at the Oceans Sciences Centre (OSC) while the on-growing takes place at a demonstration site in Bay dEspoir.

Brown says that the results to date have been encouraging. We now have a consistent supply of juveniles with minimal deformity, says Brown, so in 2004, it was decided that more attention should be paid to the quality of juveniles rather than quantity. Experiments on light intensity, tank bottom color and live feed enrichments resulted in improved survival and growth. We found that it is much easier to manage the fish if the bottom color (of the tanks) was yellow, said Brown. They hope to improve on the 20% survival rate to the juvenile stage by improving egg quality and the quality of the live feed.

But where we are really lacking is in cage husbandry, says Brown, things like stocking densities, grading, vaccinations, early maturation, feed, and feeding regimes. Feed is still a major cost we need to know what to feed and how often. He said that some of their early studies suggest that restricting feeding to every second day may be beneficial.

Early studies have shown that juveniles which are being transferred to sea cages with an empty gut undergo much less stress. Brown says there has been much progress on juvenile health. Studies concentrated on the use of immunostimulators to combat disease, comparing wild and cultured cod and the prevalence of infectious diseases, monitoring seasonal changes of parasites in the nursery and cage site, stress and immunological status of cod at different temperatures and the efficacy of Parasite-S.

The broodstock management program is in the final year of a four-year project. Its research has focused on broodstock husbandry techniques to optimize egg and larval quality from controlled spawning of captive fish. Research is being carried out at the OSC and at Winterton industrial broodstock facility. Lush works with more than 300 broodstock, half of those fish being housed at OSC. We now have our first domesticated broodstock from the 2001 and the 2002 year classes, says Lush.

The two main objectives of the project are: to determine the relationships among broodstock husbandry, feeding schedules, spawning success and post-spawning mortality and to develop effective photomanipulation techniques and assess effects on egg quality, hatching and the feeding success of larvae. Lush has divided the broodstock into three groups, and using photomanipulation has succeeded in having one group spawn in late November, (four-month advance), a second in September (six-month advance) and an ambient group spawning in late March. Egg fertilization is excellent averaging 97% and cell division abnormalities were minimal, averaging between 3-6% over all batches collected.

Lush says, feeding schedules are important, another goal is to refine seasonal feeding regimes for the broodstock. Previously, it was felt that because cod eat little during spawning, and that feeding during this time may reduce egg quality due to fecal contamination, feeding was halted at this time. However, Lush says, through research, they have proven this not to be the case. We continue feeding throughout the entire spawning period and our post-spawning mortality is nil, says Lush. She says fish are fed to satiation once a week and egg quality and the health of the broodstock is excellent.

Additional Information

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Source: Taken from the website of the British Columbia Salmon Farmers Association - April 2005

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