Production, Quality, and Low Temperature Incubation of Eggs of Atlantic Cod Gadus morhua and Haddock Melanogrammus aeglefinus in Captivity |
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| Authors: | Lawrence J Buckley Terence M Bradley Jennifer Allen-Guilmette |
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| Institution: | URI/NOAA CMER Program, Graduate School of Oceanography. University of Rhode Island, Narragansett, Rhode Island 02882 USA and NOAA/NMFS Narragansett Laboratory, 28 Tarzwell Drive, Narragansett, Rhode Island 02882 USA;Department of Fisheries. Animal and Veterinary Science. University of Rhode Island, Kingston, Rhode Island 02881 USA;Department of Fisheries, Animal and Veterinary Science. University of Rhode Island, Kingston, Rhode Island 02881 USA and NOAA/NMFS Narragansett Laboratoty, 28 Tarzwell Drive, Narragansett, Rhode Island 02882 USA |
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| Abstract: | Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus broodstock maintained under altered regimens of temperature and photoperiod spawned up to 8 mo per year. The cod broodstock produced viable embryos from October through June. The haddock broodstock produced viable embryos from December through May. Egg diameters were largest during the middle of the spawning season when water temperature was at a minimum, resulting in an inverse relationship between egg diameter and water temperature in both species. Egg quality was high, as evaluated by buoyancy, fertilization rate, regularity of early cleavage, and percent viable hatch. Low temperature incubation of cod and haddock eggs extended the embryonic period. Cod embryos tolerated a wider range of temperatures than haddock. High mortality (1 90%) was observed before hatching in haddock embryos incubated at 1 C. Atlantic cod embryos hatched at temperatures as low as —1 C, extending the embryonic period to 59 d. At 8 C Atlantic cod and haddock embryos hatched in 11–12 d. To determine if extending the embryo incubation time by using low temperatures had a detrimental effect, embryos were incubated through hatch at either 1 C or 6 C, and the larvae from both groups reared at 6 C. Growth and early survival of larvae were comparable in both treatments. |
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