EFFECTS OF SHAD DENSITY AND RESERVOIR HYDROLOGY ON THE ABUNDANCE AND GROWTH OF YOUNG-OF-YEAR CRAPPIE IN ALABAMA RESERVOIRS

We studied five Alabama reservoirs during 1992 through 1994 to explore the influence of both reservoir hydrology and larval shad (Dorosoma s pp.) on young-of-year crappie (Pomoxis spp.) recruitment. Mean relativ e abundance of age-0 crappie was slightly and negatively correlated wi th larval gizzard shad (D. cepedianum) density but not with that of la rval threadfin shad (D. petenense). Alternatively, age-0 crappie growt h was positively correlated with threadfin shad density but not with g izzard shad density, which indicated that shad were not adversely affe cting young crappie growth via competition for food. Neither crappie a bundance nor growth was related to the dates of peak larval gizzard sh ad or threadfin shad occurrence. Age-0 crappie abundance was positivel y related to mean summer (June-August) retention time in four short re tention time (< 15 d) reservoirs. However, when gizzard shad density w as included into the analysis, this variable was no longer a significa nt predictor of crappie abundance, indicating that the relation betwee n larval gizzard shad density and age-0 crappie abundance was overridd en by the influence of mean summer retention time. Our findings indica te that the potential for interactions between young crappie and shad is certainly viable, but any impacts that larval shad might have had o n age-0 crappie abundance and growth were not detected.