Temporal Trends of Young-of-Year Fishes in Lake Erie and Comparison of Diel Sampling Periods

Abstract

We explored temporal trends of young-of-year (YOY) fishes caught in bottom trawl hauls at an established offshore monitoring site in Lake Erie in fall during 1961-2001. Sampling was conducted during morning, afternoon, and night in each year. Catches per hour (CPH) of alewife (Alosa pseudoharengus) YOY were relatively low and exhibited no temporal trend. This result was consistent with the species' intolerance to Lake Erie's adverse winter water temperatures. Gizzard shad (Dorosoma cepedianum) YOY decreased sharply after 1991, which was consistent with recent oligotrophication of the lake. Following the establishment in 1979 and rapid increase of white perch (Morone americana) YOY, white bass (Morone chrysops) and freshwater drum (Aplodinotus grunniens) YOY decreased. Trout-perch (Percopsis omiscomaycus) YOY decreased during 1986-1991, but recovered to previous levels during 1991-2001. The recovery coincided with the resurgence of mayflies (Ephemoptera) in the lake. CPH of spottail shiner (Notropis hudsonius) and emerald shiner (N. atherinoides) YOY exhibited no temporal trend between 1961 and the late 1970s to early 1980s. CPH of yellow perch (Perca flavescens) YOY decreased during 1961-1988, and walleye (Sander vitreum) YOY increased overall during the time series. These observations were consistent with published studies of adults in the region. CPH of 4 of the 10 species of YOY considered were greatest during night. CPH for walleye YOY was higher in the morning than in the afternoon, but there was no significant difference between night and morning abundances. The results suggest that (1) CPH of YOY fishes may be a useful monitoring tool for Lake Erie, and (2) offshore monitoring programs that do not include night sampling periods may underestimate recruitment for several common species.

Diel Variation in Near-Shore Great Lakes Fish Assemblages and Implications for Assessment Sampling and Coastal Management

“…Great Lakes acoustic studies show diel movement of some fish species in both near-shore and offshore habitats (Mason et al 2005, Stockwell et al 2006. Enhanced nocturnal abundance and diel movement have recently been observed for several species in western Lake Erie (Stapanian et al 2006) and in Lake Ontario with the present study. The effects of diel migration and gear avoidance remain difficult to distinguish.…”

“…Some Great Lakes fish also move inshore at night and offshore in the day (e.g., trout-perch [Percopsis omiscomqcus] and white perch [Morone americana]) or engage in vertical migrations following plankton (e.g., emerald shiner [Notropis afherinoides]) (Scott and Crossman 1973, Smith 1985, Stapanian et al 2006). Recent acoustic work shows that lake herring (Coregonus artedi) migrate daily, especially at early life stage (Mason et al 2005, Stockwell et al 2006.…”

Recruitment of burbot (Lota lota L.) in Lake Erie: an empirical modelling approach

“…For 128 of these models, we included as independent variables all combinations of one to all seven of the indices described above. In all analyses, our index of burbot recruitment from each year class was treated as statistically independent (e.g., Stapanian et al 2007b). Residuals from the models satisfied assumptions of normality (Kolmogorov-Smirnov test, P > 0.7).…”

Fish Entrainment Rates through Towboat Propellers in the Upper Mississippi and Illinois Rivers

“…The trawling gear (blocks and winches) was relatively simple to set up. Safety concerns restricted sampling to daylight hours and precluded nighttime sampling, which might have yielded different results (Butterworth and Coles 1977;Stapanian et al 2007). Entrainment estimates were limited to 12.5-cm or larger fish.…”