Overwintering Paddlefish in Monoculture and in Polyculture with Channel Catfish and Rainbow Trout

Paddlefish, "Polydon spathula," overwintered in monoculture and in polyculture with fingerling channel catfish, "Ictalurus punctatus," or with rainbow trout, "Oncorhynchus mykiss," were examined for growth and compatibility in nine 0.04-ha ponds. Paddlefish in polyculture had significantly greater (P ≤ 0.05) individual weight gains than those in monoculture. Feed in polyculture treatments probably served as a fertilizer, promoting zooplankton production for paddlefish consumption and growth. Paddlefish in polyculture with fingerling channel catfish had significantly greater (P < 0.05) individual weight gains than paddlefish polycultured with rainbow trout, although there was less feed input with channel catfish than with rainbow trout. Bloody and frayed fins on paddlefish stocked with rainbow trout suggested fin nipping by rainbow trout which may have interfered with paddlefish feeding and growth. Paddlefish overwintered in polyculture with fingerling channel catfish demonstrated increased weight gains and good species compatibility.