Can fisheries yield be enhanced by large-scale feeding of a predatory fish stock? A case study of the Icelandic cod stock

• Published in: Canadian Journal of Fisheries and Aquatic Sciences
• Main Author: Björnsson, Björn
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 2001
• Subjects: Aquatic Science; Ecology, Evolution, Behavior and Systematics; Gadus morhua; Iceland
• Online Access: http://dx.doi.org/10.1139/f01-144; http://www.nrcresearchpress.com/doi/pdf/10.1139/f01-144

The concept of large-scale feeding of a predatory fish stock by natural prey species is introduced and evaluated for the Icelandic cod (Gadus morhua L.) stock. The paper addresses the question of whether fisheries yield can be enhanced by relocating food supply in an ecosystem from areas of surplus prey abundance to areas where predator abundance is high and prey abundance low. The benefits of large-scale feeding may be threefold. First, it may increase the growth rate and yield of a predatory fish stock. Second, it may reduce predation on valuable species. Third, it may lower the cost of fishing. For large-scale feeding to be economically feasible it is necessary to have access to large quantities of inexpensive and high-quality feed. In Iceland about 1 000 000 t of capelin, herring, and blue whiting are landed annually for fishmeal production, their price being less than 10% of that of cod. For much of the year these stocks are outside the distributional area of the Icelandic cod stock. The most cost-effective feeding technique must involve purse seiners and pelagic trawlers transporting their catch directly to the feeding locations. Different feeding scenarios, harvesting techniques, and ecological consequences are considered for the Icelandic cod stock.