L. E. Miranda

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...

Food and growth of age-O hybrid striped bass (Morone saxatilis x M. chrysops) were examined during June-November 1988-1989 in Ross Barnett Reservoir, Mississippi. Shads (Dorosoma spp.), especially threadfin shad (D. petenense), made up about 70%-90% of the diet by weight. Other fish made up about 3%-20% of the diet and were eaten primarily by hybrids < 150 mm total length. Invertebrates constituted a small percentage of the diet, and were eaten mostly by fish <100 mm and not by those> 150 mm. By November, the length of age-O fish averaged 241 mm in 1988 and 227 mm in 1989....

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...

We conducted tests to quantify delayed mortality of white crappie (Pomoxis annularis) after catch and release by anglers. White crappie were subjected to I) catch and release in shallow water using traditional hook-and-line methods and 2) rapid depressurization to simulate catch in deep water. Mortality 6-11 days after catch and release from shallow water averaged 3%. No significant differences (P > 0.05) were detected between mortality rates of white crappie 15-25 cm and >25 cm total length, nor between fish caught using live and artificial baits. No mortalities occurred 96 hours...

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...

We conducted laboratory and field investigations to detennine the relative value of shads (Dorosoma spp.) and sunfishes (Lepomis spp.) as prey for largemouth bass (Micropterus salmoides). In the laboratory, we examined the energy content of gizzard shad (D. cepedianum) and bluegill (L. macrochirus) and digestibility by largemouth bass. Although the ratios of proximate components in the 2 prey species differed, total energy contents as calories per gram were equal. The rates at which gizzard shad and bluegill were digested were similar at feeding rates <1.5%-2.0% of largemouth bass body...

Electrofishing for largemouth bass (Micropterus salmoides) in sites selected because they are judged to have habitat favored by bass can often yield higher catch per effort than in sites selected randomly, resulting in reduced effort or more precise estimates. Although samples selected subjectively could misrepresent relative abundance, they mayor may not affect population indices derived from lengthweight data, such as length-frequency and condition indices. We compared indices obtained at randomly-selected sites with indices obtained at subjectively-selected sites. The latter sites...