Rainbow Trout Cage Culture and Benthic Production in East-Central South Dakota Dugouts

Forty-five cages, encompassing 1.0 m3 of water, distributed between three dugout ponds, were stocked with rainbow trout (Salmo gairdneri) fingerlings to determine the feasibility of raising annual fish crops. Growth rates were compared between feeding rate (0, 3, and 5% body weight/day [bwt/day]) and stocking rate (35, 52, and 70 fish/cage). Growth was significantly (P ≤0.05) greater at feeding rates of 3 and 5% bwt/day than 0% bwt/day. The fish fed 0% bwt/day decreased in mean weight by 0.7 g; the weight gain for the 3 and 5% bwt/day feeding rates were 47.2 and 45.2g, respectively. Significant differences (P ≤ 0.05) in growth were detected between stocking rates. Mean survival for the three feeding rates was 98%. Natural food contribution was significantly lower (P ≤ 0.05) for the 3 and 5% feeding rates, than the 0% bwt/day. Stomachs contained 2.6, 1.3, and 12.8 organisms/stomach for these respective treatments. While cage culture was not commercially feasible due to small harvest site, low stocking rate, and small cage size, trout were large enough for consumption