Feeding Behavior, Food Consumption, Growth, and Survival of Hybrid Grass Carp in Two South Dakota Ponds

Abstract

Abstract Plant selection of yearling hybrid grass carp produced by crossing female grass carp (Ctenopharyngodon idella) with male bighead carp (Hypophthalmichthys nobills) was examined under controlled conditions at Gavins Point National Fish Hatchery and under field conditions in two ranch ponds in south-central South Dakota. In feeding trials conducted in a 0.07 hectare hatchery pond, the hybrids selected Najas guadalupensis, Chara sp., and Potamogeton pectinatus, but avoided Ceratophyllum demersum and Myriophyllum spicatum. Field observations verified that Najas guadalupensis was selected and Ceratophyllum demersum was avoided. Hybrid grass carp averaging 51.3 g were stocked in two ponds at rates of 17.0 and 32.2 kg/hectare, respectively. No discernible reduction in aquatic vegetation was attained by the hybrid by the end of the summer. Feeding activity was diurnal and occurred primarily in shallow water. Total daily food consumption was 44.0% of body weight at 23 C and 30.4% at 15 C. Based on plant co...