From 1983 co 1985, more than 1,000 channel catfish (Icatalurus punctatus) were sampled with rotenone from 50 streams and rivers in Iowa to assess differences in population densities, standing stocks, viral statistics, age and growth, and habitat use Catfish densities ranged from 5 fish/ha in sites on the South Skunk and Upper Iowa Rivers to more than 4,400 fish/ha at a site on the Thompson Fork of the Grand River. Standing stocks ranged from a low of 0.1 kg/ha on a site on the South Skunk River to a high of 467 kg/ha on the East Fork of the Des Moines River. In general, catfish in rivers grew at a slower rate than lake populations (taking about four years to reach 305 mm), but total annual morality was relatively low compared to one published lake population, usually between 20 and 35% for fish age III and older. Larger catfish were usually found in streams of larger watersheds, but headwater streams were important nursery areas for fish less than age III. Mean standing stocks of channel catfish were similar between landforms (P\u3e0.05), but both relative weight (W,) of channel catfish and PSD was higher (
