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 crappie Pomoxis annularis, brown bullhead Amieurus nebulosus, black bullhead A. melas, goldfish Carassius auratus, and common carp Cyprinis carpio. The dominant species in the undiked area were white perch Morone americana, gizzard shad Dorosoma cepedianum, white crappie, brown bullhead, and yellow perch Perca 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.

Breeding bird use and wetland characteristics of diked and undiked coastal marshes in Michigan

“…Prince () compared bird use of diked and undiked sites, but focused on wetlands associated with rivers located inland from Michigan's coasts. Differences in invertebrates (McLaughlin and Harris , Provence ), fish (Johnson et al , Markham et al ), plant foods for waterfowl (Brasher et al ), and plant communities (Thiet , Herrick and Wolf , Herrick et al ) have been investigated, but we found no other studies evaluating bird use of diked Great Lakes coastal wetlands. Our goal was to compare breeding bird use, vegetation composition and structure, and physical attributes of diked and undiked coastal marshes to evaluate current management for wetland birds.…”

“…Connections to the Great Lakes, shallower water depths, and lesser amounts of aquatic vegetation at undiked wetlands likely increased access to forage fish. Studies of Lake Erie coastal wetlands indicated differences between diked and undiked sites in fish species richness and abundance, age class frequencies, lengths, and body condition for some species (Johnson et al , Markham et al ). Foraging may have been more difficult for Forster's terns in diked wetlands because of greater coverage of floating vegetation.…”

Fish Assemblages, Connectivity, and Habitat Rehabilitation in a Diked Great Lakes Coastal Wetland Complex

“…Despite acknowledged difficulties in reducing nutrient and sediment loads from Lake Erie watersheds, it seems that hydrologic reconnection of these and similar diked wetland units could be a relatively easy means to bolster coastal Lake Erie fish populations. Differences between fish assemblages in coastal and diked wetlands have been noted for many years (Johnson 1989;Johnson et al 1997;Markham et al 1997;Bouvier 2006), but this study demonstrated that (1) many fishes access even degraded Lake Erie coastal wetland habitats (e.g., those with poor water quality and invasive plant species) throughout the year; (2) there are large seasonal variations in patterns of utilization by many fishes; and (3) there may also be ecological risks involved with hydrologic reconnection, including increased nutrient loading and turbidity, reduced SAV coverage in connected coastal marshes, and increased facilitation of invasive plants.…”

Coastal Wetland Support of Great Lakes Fisheries: Progress from Concept to Quantification

“…Shoreline clearing and hardening are also associated with degraded vegetation structure in GLCWs (e.g., Trebitz et al 2009b;Uzarski et al 2009) and tend to reduce spawning habitat (Reed and Pereira 2009). Disruption of the normal connectivity between GLCWs and the adjacent lakes is another condition that is detrimental to support for fishery-relevant species (Johnson et al 1997;Jude et al 2005). Restoring hydrologic connectivity is a major thrust of restoration on marine coasts (e.g., Montalto and Steenhuis 2004) and is expected to enhance the number and size of fishery-relevant species in GLCWs (Bouvier et al 2009).…”