Publisher: Nofima AS
Number of pages: 25
International Standard Numbers:
Open Access: green
Capture based aquaculture of Atlantic cod is currently being developed in Norway. This is likely to happend in concert with traditional fisheries, where wild caught cod can be kept in cages for feeding either to improve quality or to improve the capacity to serve the markets at times that fresh caught cod is less readily available. Feeding of cod in captivity will most likely be based on use of commercially available pelleted dry feed. This is due to several advantages as compared to use of whole fish or moist feed. Dry pellets is however very different from the natural prey of wild cod, most important is probably texture and water content. Soaking dry pellets in water to increase water content and soften the feed have shown promising in practical farming. This is however a labour intensive operation, and impose several management callenges, such as the need to start preparations the day before hence need to predict future appetite, logistics, loss of water soluble components and hygiene. Using vacuum to draw water into dried pellets may solve this problem. In this project, these two methods for adding water are compared and the resulting growth of captured cod measured. Use of attractants have shown promising results in other species, so a commercial available attractant is added in one treatment in order to stimulate appetite and thus improve weaning success. Fish offered feed with water added using vacuum grew at least as good as fish feed on pellets soaked in water overnight. No positive effects of adding the attractant was observed.