Fish communities in a diked Lake Erie wetland and an adjacent undiked area

Abstract

Most (84%) of Ohio’s remaining Lake Erie wetlands are diked to maximize food production and habitat for migrating waterfowl. Typically these wetlands are partially drained during spring and refilled the following fall. Fish populations have not been managed extensively, probably because few quantitative data are available on fish communities in diked wetlands and on how water-level manipulations affect these communities. We used trap nets to sample fish monthly (April–August) in diked West Marsh and in the formerly diked Muddy Creek Bay. We compared fish communities on the basis of species richness, composition, and equitability; relative abundance; and mean length and body condition of species common to both areas. We collected 23 species from the diked area and 40 species from the undiked area. Although there were more species collected in the undiked area, species equitability was greater in the diked wetland. The five most abundant species in the diked wetland were white crappiePomoxis annularis, brown bullheadAmieurus nebulosus, black bullheadA. melas, goldfishCarassius auratus, and common carpCyprinis carpio. The dominant species in the undiked area were white perchMorone americana, gizzard shadDorosoma cepedianum, white crappie, brown bullhead, and yellow perchPerca flavescens. Neither area contained a classical, diverse wetland fish community. Mean lengths of white crappie, common carp, goldfish, and brown bullhead were significantly greater from the undiked area during all months. Body condition indices of > 150 mm white crappies and > 225 mm brown bullheads were significantly greater in the undiked area after June The large differences in length and condition indices indicate that fish communities in the diked wetland may be biologically isolated from those in the adjacent undiked area. This has management implications given that an almost complete exchange of water occurs annually and could result in extensive movement of fish in and out of the diked wetland. Management strategies compatible with or enhancing existing wildlife management strategies need to be developed for improving fish communities in diked wetlands and enhancing their contribution to Lake Erie.