Aspects of the Feeding Ecology of Gizzard Shad in Acton Lake, Ohio

Diel feeding periodicity of gizzard shad (Dorosoma cepedianum) in Acton Lake, Ohio, was studied in 1973 and 1974. Grazing on bottom sediments by age-I and age-II gizzard shad usually began in early morning, increased in intensity until 1400–1600 hours, and then declined. After dusk, the fish became inactive, and feeding activity ceased. Exceptions to this pattern were noted in May and June 1974, when food intake decreased markedly during the spawning period. Organic and caloric contents of detrital food material in the gizzards ranged from 3.1 to 61.5% (mean = 18%) of dry weight and 845 to 5,520 cal/g ash-free dry weight (1973, mean = 3,187; 1974, mean = 3,132). The low quality (expressed as calories) of the organic detritus ingested during most of the summer could explain in part why the growth rates of gizzard shad in this system are depressed in relation to those observed in other impoundments at similar latitudes.