水産および畜産生産

抽象的な

Preliminary Examination of Cultured Fish Consumption by the Diamondback Water Snake Nerodia rhombifer

Perschbacher P* and Davis M

The black hole so called for the lack of accounting, in aquaculture may account for unexplained losses of 20% or more per year in cultured organisms. Among potential causes are poor water quality and disease episodes, predation by birds, mammals, and reptiles/amphibians, and theft. At the Aquaculture Research Station of the University of Arkansas at Pine Bluff the diamondback water snake was commonly encountered. These live-bearing snakes of up to 2 m in length were observed consuming cultured channel catfish and baitfish, including goldfish. To begin to assess their capacity for damage, we held 3, 0.6-0.9 m adult snakes in large tanks. Each tank was supplied with a small water source for the goldfish, golden shiners and catfish fingerlings added, ad libitum. The consumption was monitored for three weeks. Consumption was no fish, 5 fish, and 1 fish; for an average of 0.7 fish/individual/week. Based on daytime observations of 5-10 snakes per 0.1 ha pond (likely an underestimate due to nocturnal activity in warm weather and under harassment) at the station and these results, an estimated loss of 5-10% per year may be expected.