Utilization of Ohio River Shallow Water Habitats by Young-Of-The Year Fishes

Abstract

Between 9 June and 11 November, 1981 and 9 June and 8 October, 1982, 149 samples were collected from selected backwater and mainstem sites of the middle Ohio River (between river mile 339 and 424). Sites were collected at approximately triweekly intervals during 1981 and bi-weekly intervals in 1982 using a 10m x 2m bag seine with 2m x 2m bag, 5.5mm ace mesh wings, and 2mm ace mesh bag. Analysis of young-of-the-year fishes collected indicates that backwaters are more important than mainstem martins in terms of number of species supported, relative frequencies and comparative densities. Total number of species collected from backwaters was fifty-four, from mainstem margins forty two. Twenty-one species were collected in sixty percent or more of the backwater samples, compared to six species collected in sixty percent of samples for mainstem margins. Comparative densities as analyzed by the T-test were significantly higher (at the 0.5 level), for a greater number of species in backwaters (16) than mainstem margins (0). In terms of relative abundance, emerald shiners (Notropis atherinoides) dominated mainstem margins (96% of total numbers collected). Others present in high relative abundance for mainstem margins included gizzard shad (Dorosoma cepedianum - 1.5%), mimic shiner (Notropis volucellus - 1.3%), and river shiner (Notropis blennius - 1.0%). Many species were present in relatively high abundances in backwaters. Gizzard shad (D. cepedianum) and emerald shiners (N. atherinoides) comprised the majority of fishes collected (54% and 23% respectively), followed by mimic shiner (N. volucellus - 5.0%), bluegill (Lepomis macrochirus - 4.0%), silver chub (Hybopsis storeriana - 3.0%), bluntnose minnow (Pimephales notatus - 2.0%), river shiner (N. blennius - 2.0%), freshwater drum (Aplodinotus qrunniens - 1.7%), bullhead minnow (Pimephales viqilax - 1.2%), ghost shiner (Notropis buchanani - 0.6%), white bass (Morone chrysops - O.6%), river carpsucker (Carpiodes carpio - 0.5%), longear sunfish (Lepomis meqalotus - 0.5%), sauger (Stizostedion canadense - 0.4%), spotted bass (Micropterus punctulatus - 0.3%), golden redhorse (Moxostoma erythrurum - 0.2%), and spotfin shiner (Notropis spilopterus - 0.2%). Dietary habits of the fourteen most abundant young-of-the-year species from 1982 were examined over three dates (21 July, 26 August, and 7 October) during the course of the 1982 summer period. These species included N. atherinoides, D. cepedianum, N. volucellus, L. macrochirus, N. blennius, H. storeriana, P. notatus, A. qrunniens, P. viqilax, M. chrysops, C. carpio, L. meqalotus, M. punctulatus, and S. canadense. A totaT of 26 different items were found to be consumed by the above species. Analysis of diet-overlap was performed using the Schoener Index. Those species which exhibited significant diet overlap (above 0.60) included the following species pairs: N. volucellus - D. cepedianum; P. notatus - D. cepedianum; P. viqilax - H. storeriana; A. qrunniens - H. storeriana; L. meqalotis - H. storeriana; P. notatus - N. volucellus; P. notatus - P. viqilax; M. punctulatus - M. chrysops; STcanadense - M. chrysops; S. canadense - M. punctulatus; and L. meqalotus - A. qrunniens. Summer growth rates of the fourteen most abundant young-of-the-year species from 1982 was also examined. Fish were measured using total length. Determination of growth rate was also performed. In general growth of young-of-the-year was comparable to that reported by other authors for other geographical areas. Noticeably slower growth was found in the freshwater drum (A. qrunniens), noticeably higher growth in the white bass.