M. S. Schorr

We investigated effects of selected physical factors on the catch rate of white crappie (Pomoxis annularis) in trap nets in Mississippi lakes. Population data were collected on 7,782 white crappie from 557 trap-net samples in the fall (N = 4,679 fish/243 nets) and spring (N = 3,103 fish/314 nets), 1987-1989. Generally, catch/day (N fish/24 hours) estimates were higher and less variable in trap nets set at water depths of 1.0-2.9 m and on bottom slopes of 0.0%-7.9%. Catch/day estimates were higher, but equally variable, in trap nets set perpendicular to the shoreline and at water...

We investigated the relation among estimates of abundance and size structure of white crappie (Pomoxis annularis) determined with electrofishing, trapnetting, and rotenone sampling in 4 Mississippi lakes in 1987-1989. We also examined the relations between angler harvest and estimates provided by each gear to determine whether estimates made by sampling could be used to index angling success. Electrofishing yielded 4 fish/man-hour in fall and 6 in spring, and trapnetting yielded 24 fish/manhour in fall and 9 in spring; rotenone sampling during summer yielded 8 fish/man-hour. Estimates of...

The effects of soak time and fish density on number and size of white crappie (Pomoxis annularis) caught with trap nets were investigated in Mississippi lakes. Catch/set (1-7 days) of large white crappie (≥200-mm total length) increased asymptotically with soak time, but that of small and medium fish (<130 and 130-199 mm, respectively) decreased after the first 2-3 days. Catch/day of all length groups of white crappie, increased sharply with soak time, peaked in 1-3 days, and decreased thereafter. These trends indicated that catch could be optimized if nets were run every 2-3 days, and...