Identifying Relationships between Catches of Spawning Condition Yellow Perch and Environmental Variables in the Western Basin of Lake Erie

Although the reproductive behavior of yellow perch Perca flavescens has been well documented in small systems, relatively little is known about the spawning preferences of yellow perch in large systems, such as the Laurentian Great Lakes. During 2006 and 2007, we compared the presence and abundance adult yellow perch during the spring spawning season with environmental variables in the western basin of Lake Erie. We also estimated the timing of yellow perch spawning by comparing the relative abundance of gravid and spent females collected in our trawls and then comparing the proportion of gravid females with environmental conditions at our sampling sites. Overall, the probability of catching adult yellow perch and the catch per unit effort increased with increasing bottom temperatures in the spring, whereas the probability of catching gravid females increased with increasing Secchi depth. However, the relationships between our catch metrics and environmental variables were not consistent across years, possibly as a result of the very strong 2003 year-class, which became first-year spawners in 2006. We also documented that yellow perch spawning occurred when bottom temperatures were between 11◦C and 15◦C in the western basin; these temperatures were reached on different dates in different parts of the basin and in different years. Thus, we suggest that management agencies consider basing the start of the commercial fishing season on prevailing bottom temperatures rather than using a set date across years and sites. The reproductive behaviors of yellow perch Perca flavescens and the closely related Eurasian perch P. fluviatilis have been intensively studied. In North America, yellow perch spawning occurs annually during the spring or early summer as water temperatures approach 8–10◦C (Keast 1968; Forney 1971), but considerable variation in peak spawning temperatures and spawning duration exists across the geographical range of this *Corresponding author: [email protected] 1Present address: Cooperative Institute for Limnology and Ecosystems Research, School of Natural Resources and Environment, University of Michigan, G110 Dana Building, Ann Arbor, Michigan, 481009-1041, USA. Received December 4, 2009; accepted October 6, 2010 Published online February 15, 2011 species (Hokanson 1977). For example, northern populations may initiate spawning behavior at lower temperatures and at a later date and may have a shorter duration of spawning than southern populations (Thorpe 1977). In small systems, female yellow perch attach egg skeins—a buoyant, gelatinous matrix in which the eggs are embedded—across vegetation and woody debris in shallow areas (Nelson and Walburg 1977; Thorpe 1977). Although considerable research has been conducted to describe yellow perch spawning behavior and habitat selection in small lakes, relatively little is known about the spawning habitat of yellow perch in large systems, such as the Laurentian Great Lakes. Due to the large amount of wave energy generated along the shorelines of large systems (e.g., Lake Erie), the vegetated habitat typically used for spawning in small inland lakes is rare in large systems, particularly during the early spring. Goodyear et al. (1982) suggested that yellow perch spawning occurs along the entire southern shore of Lake Erie and that spawning areas are evenly dispersed from the mouth of the Niagara River (eastern basin) to the mouth of the Detroit River (western basin). However, the shallow-water habitats along this shoreline vary widely in substrate types, coastal geomorphology, and wave exposure, so spawning is unlikely to be evenly distributed along the shoreline. Previous studies have shown that yellow perch spawning in large systems does not occur randomly but is concentrated in areas of preferred depths and substrates (Thorpe 1977; Jones 1982; Robillard and Marsden 2001). For example, given the buoyancy of their eggs, yellow perch spawning in large systems that lack vegetation may prefer areas where eggs can be attached to stable substrates. Such spawning behavior has been observed in Lake Michigan, where catches of male yellow