Peter A. Hackney

Threadfin shad (Dorosoma petenense) impingement at the Tennessee Valley Authority's Cumberland Steam-Electric Plant followed a seasonal pattern related to the abundance and length distribution of young-of-year fish. Electrofishing samples taken near the plant showed a similar pattern. The number ofimpinged fish (larger than 50 mm) decreased rapidly with increasing length due to reduction in abundance by natural mortality. Impingement mortality was found to be length dependent. Most individuals. less than 50 mm in length passed through the screens, while increasingly larger individuals were...

Spawning behavior, age and growth, and sport fishery for the silver redhorse, Moxosloma anisurum (Rafinesque), in the Flint River, Madison County, Alabama, were studied in 1969 and 1970. Spawning silver redhorse were first observed on April I, 1969, and April 8, 1970, at a water temperature of I 4.4° C. (58° F.) Females appeared to mature between the sixth and seventh year at a length of 548-600 mm. Males appeared to mature at 510-530 mm., but most seemed to mature at the same age. Growth of males and females was approximately the same until age group VI. After this age, males grew slower...

Severe reduction in number of river redhorse, Moxostoma carinatum (Cope), has occurred in Alabama and the southeast during recent years. The Cahaba River is one of the last strongholds for this species in Alabama. Electrical shocking equipment was utilized during this study. Two hundred eighty-six adult river redhorse were captured, tagged, and returned to the Cahaba River. Redhorse were observed spawning on gravel shoals during April, 1966 and April, 1967 with water temperatures ranging from nOF. to 76° F. Egg counts made on river redhorse ranging in size from 17.9 inches to 22.1...