Survival and Growth of Rainbow Trout (Salmo gairdneri) in Four Prairie Lakes, North Dakota

Abstract

Survival of rainbow trout (Salmo gairdneri) in three North Dakota prairie lakes was low the 1st mo after stocking, ranging from 15 to 54%; high mortality may have been due to bird predation. In a fourth lake, where 77% survived the 1st mo, no predatory birds were observed. All fish in two lakes died in August when dissolved oxygen levels dropped to below 1.0 mg/liter following July blue-green algae blooms of 28 and 63 mm³/liter. In the other two lakes, harvests in October ranged from 0.1 to 4.4% of fish stocked. Mean wet weights at harvest of up to 272 g were sufficient for commercial use; however, special management to improve survival rates would be necessary in the lakes studied.