Effect of diet on growth and survival of coho salmon and on phosphorus discharges from a fish hatchery
Fisheries Bioengineering Symposium: American Fisheries Society Symposium 10
Colt J;White RJ;
American Fisheries Society
In two hatchery experiments, coho salmon Oncorhynchus kisutch were fed a low-phosphorus diet or Oregon Moist Pellets (OMP) for 45-46 weeks from starting weights of 4-5 g to their release as smolts to Lake Michigan. In the first experiment, fish fed the low-phosphorus diet grew 85% as well as and returned from Lake Michigan at 79-106% the rate of fish fed OMP, and their hatchery effluent contained 33-80% less phosphorus. In the second study, the low-phosphorus diet was modified to contain 10% fish meal in an attempt to increase growth rate. Fish fed the modified diet (T2M) grew as well as those fed OMP and discharges of phosphorus were significantly reduced. The amounts of phosphorus discharged per 1,000 kg of fish production were 4.8 and 12.2 kg for the T2M and OMP diets, respectively. The amounts of phosphorus discharged per 1,000 kg of feed fed were 4.2 and 8.2 kg for the T2M and OMP diets, respectively. Overall, when coho salmon were fed the T2M diet, the amount of phosphorus discharged into effluents was reduced by 49-61% compared with discharges from the OMP treatment.