DAVID S. HICKMAN AND MATTHEW J. SABO, School of Forestry, Wildlife, and Fisheries, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, Louisiana 70803, USA

The Atchafalaya River Basin is the most popular bass fishery in Louisiana and contains areas that are chronically hypoxic. We used hook and line to capture largemouth bass from a normoxic habitat (daily minimum dissolved oxygen > 5 mg/L) and a hypoxic habitat (daily minimum dissolved oxygen < 2 mg/L) and released the fish into net pens that were checked daily for 14 d. Four treatments were performed: fish caught from the normoxic habitat and released into pens in the normoxic habitat, fish caught from the normoxic habitat and released into pens in the hypoxic habitat, fish caught from the hypoxic habitat and released into pens in the hypoxic habitat, and fish caught from the hypoxic habitat and released into pens in the normoxic habitat. Fish caught from the normoxic habitat and released into pens in the hypoxic habitat experienced higher mortality rates than fish from the other treatments. We concluded that largemouth bass can be angled from hypoxic water without greatly increasing their susceptibility to hooking mortality, but when angled from normoxic water and released into hypoxic water their incidence of hooking mortality rises. Angling tournaments in the Basin should adopt guidelines governing the handling and release of fish in relation to prevailing oxygen conditions.