Food Habits and the Utilization of Drift Organisms by Larval Fishes in the Middle Fork of Drakeu27s Creek, Kentucky

摘要

Food habits of larvae of the northern hog sucker, common shiner, rosyface shiner, and Micropterus sp. from the Middle Fork of Drakeu27s Creek, Kentucky were identified from 18 March to 12 August 1982. Eighteen taxa of animals were observed in the stream drift and a total of seventeen taxa, including larval fish, were identified in the stomach analysis. Eggs, rotifers, hydracarina, and diptera represented the greatest component of the drift comprising 34%, 32%, 8%, and 6%, respectively. The major organisms observed in the gut analysis included eggs (fish, rotifer, and copepod species), rotifers (Euchlanis sp.), diptera (Chironomidae), annelida (Naididae), copepoda (cyclopoids), and cladocera (Alona, Camptocerus, and unknown spp.). The northern hog sucker had the most diverse diet ingesting 15 different taxa, whereas the rosyface shiner consumed only 8 taxa. Rosyface shiners selected for rotifers in their diet during their first four weeks of life and dipterans during the last two weeks as larvae (Ivlevu27s Electivity Index). Common shiners selected for a greater variety of organisms during their first week while selecting only for dipterans during their last week. Northern hog suckers selected annelids, dipterans, and copepods throughout their larval period. Micropterus sp. selected rotifers, annelids, cladocerans, and copepods during their first two weeks and annelids, cladocerans, and copepods during their last four weeks as larvae. Piscivory was observed in Micropterus, sp. during the third week of life with 12% of the meta-larvae consuming other larvae. With the exception of Micropterus sp., larvae ingested progressively more taxa as they developed from proto meta-larvae. The greatest percentage of empty stomachs in all species was observed in the pro-larvae and the fewest in the meta-larvae. Likewise, the rosyface shiner had the greatest percentage of empty stomachs of the four major species studied. Even as larvae, the four species studied demonstrated resource sharing and positive interrelationships in their food habits.