We compared small‐mesh (4‐mm) fyke netting and boat electrofishing for sampling a littoral fish assemblage in Muskegon Lake, Michigan. We hypothesized that fyke netting selects for small‐bodied fishes and electrofishing selects for large‐bodied fishes. Three sites were sampled during May (2004 and 2005), July (2005 only), and September (2004 and 2005). We found that the species composition of captured fish differed considerably between fyke netting and electrofishing based on nonmetric multidimensional scaling (NMDS). Species strongly associated with fyke netting (based on NMDS and relative abundance) included the brook silverside Labidesthes sicculus, banded killifish Fundulus diaphanus, round goby Neogobius melanostomus, mimic shiner Notropis volucellus, and bluntnose minnow Pimephales notatus, whereas species associated with electrofishing included the Chinook salmon Oncorhynchus tshawytscha, catostomids (Moxostoma spp. and Catostomus spp.), freshwater drum Aplodinotus grunniens, walleye Sander vitreus, gizzard shad Dorosoma cepedianum, and common carp Cyprinus carpio. The total length of fish captured by electrofishing was 12.8 cm (95% confidence interval = 5.5–17.2 cm) greater than that of fish captured by fyke netting. Size selectivity of the gears contributed to differences in species composition of the fish captured, supporting our initial hypothesis. Thus, small‐mesh fyke nets and boat electrofishers provided complementary information on a littoral fish assemblage. Our results support use of multiple gear types in monitoring and research surveys of fish assemblages.

We evaluated the effects of fisheries management on food webs in three northern Wisconsin lakes with exotic rainbow smelt (Osmerus mordax). In two of the lakes, restrictions on fishing reduced mortality rates on adult walleye (Sander vitreus) during the study period. In these lakes, walleye populations increased concurrently with a decline in rainbow smelt populations. As rainbow smelt populations declined in both lakes, native cisco (Coregonus artedi) populations increased. Our analysis of walleye diets illustrated that walleye fed selectively on rainbow smelt but did not feed on cisco during the summer months. When entered into bioenergetics simulations, this information demonstrates that walleye predation alone was enough to cause the observed rainbow smelt declines in our study lakes. Our results indicate that increased walleye density allows for a parallel increase in cisco density. Based on our results, fishery regulations to restore walleye to high densities in lakes invaded by rainbow smelt may restore native planktivores that have co-evolved traits.

1. We sampled along a nearshore transect (10-m bathymetric contour) in Lake Michigan to determine diet, 24-h feeding periodicity, daily ration and food requirements of an invasive fish, the alewife, Alosa pseudoharengus, relative to zooplankton abundance and production. Our objective was to determine whether the alewife controls the abundance of two invasive, predatory cladocerans, Bythotrephes longimanus and Cercopagis pengoi. 2. Bosminidae was the most abundant prey taxon and Chydoridae, Leptodora, Chironomidae and Bythotrephes were the least abundant. Neither Bythotrephes nor Cercopagis were important prey for small alewives (£100 mm). Bythotrephes was eaten by over 50% of large alewives (>100 mm) and accounted for 10-27% of the diet weight. Cercopagis was eaten by about 30% of the large alewives but only accounted 1% of the diet weight. 3. Food weight in stomachs was highest early in the night for small alewives and lowest at night for large alewives. Chironomidae and large Chydoridae were the preferred prey of small alewives. Bythotrephes and large Chydoridae were the preferred prey for large alewives. 4. Food requirements of alewife were much less than production for most prey taxa, although the consumption of Bythotrephes greatly exceeded production on both dates. Alewives consumed only 3% of Cercopagis production. High selectivity and food requirements of alewife for Bythotrephes, and low selectivity and food requirements for Cercopagis, probably explain the difference in abundance between these two invasive cladocerans at our nearshore site in Lake Michigan.