Diet Overlap and Predation between Smallmouth Bass and Walleye in a North Temperate Lake

Competitive interactions between walleye (Sander vitreus) and smallmouth bass (Micropterus dolomieu) under various controlled conditions

“…Previous field studies have indicated some or complete diet overlap between the two species (Fedoruk 1966;Johnson and Hale 1977;Frey et al 2003;Fayram et al 2005;Bacula 2009;Wuellner et al 2010), but none indicated that prey resources were limiting, which would be a necessary criterion for competition (Crowder 1990). Controlling prey availability allowed us to examine both inter-and intraspecific competitions between WAE and SMB at two life stages and under different light conditions and prey resources while also examining feeding behaviors to help elucidate competitive mechanisms; this provided for a more complete understanding of potential interspecific competition that may occur in nature.…”

“…Walleye (Sander vitreus) is another native species that could potentially compete with SMB. Food habits studies of walleye (WAE) and SMB in sympatry describe at least some level of prey resources shared between the two species (Fedoruk 1966;Johnson and Hale 1977;Frey et al 2003;Fayram et al 2005;Bacula 2009;Wuellner et al 2010). To date, no study has examined competitive mechanisms of WAE and SMB under controlled conditions (Wuellner 2009).…”

“…Feeding at different times of the day may help partition shared prey resources along a temporal scale (Pianka 1973). Finally, SMB is considered to be a generalist feeder, readily consuming both fish and invertebrates (Clady 1974;Hubert 1977;Johnson and Hale 1977;Winemiller and Taylor 1987;Frey et al 2003;Lott 1996;Gangl et al 1997;Bacula 2009), while WAE is considered to be more piscivorous in its feeding habits (Knight et al 1984;Lyons 1987). Plasticity in food habits of at least one species may allow interspecific competitors to co-exist by reducing demand for a prey resource (Gerking 1994).…”

Anomalous Spawning of Smallmouth Bass in Nebish Lake, Wisconsin: Implications for Early Spawning and Over-Winter Survival

“…It is also presumed that producing eggs earlier confers greater fitness to offspring because earlier-spawned individuals can attain greater size during the growing season by acquiring more food and can reduce size-dependent mortality (Oliver et al 1979, Latto 1992, Ludson and DeVries 1997. Because mortality of young-of-year smallmouth bass can exceed 95% by early fall (Frey et al 2003), increased growth of earlier-spawned young-of-year is believed to translate into increased survival.…”

“…It is also presumed that producing eggs earlier confers greater fitness to offspring because earlier-spawned individuals can attain greater size during the growing season by acquiring more food and can reduce size-dependent mortality (Oliver et al 1979, Latto 1992, Ludson and DeVries 1997. Because mortality of young-of-year smallmouth bass can exceed 95% by early fall (Frey et al 2003), increased growth of earlier-spawned young-of-year is believed to translate into increased survival.Another presumed ecological advantage that the larger, earlier-spawned young-ofyear smallmouth bass have is that by attaining a larger size these fish are more prepared for the rigors of over-winter survival, a period of time when little feeding occurs (Oliver et al 1979, Shuter et al 1980. Shuter et al (1 980) demonstrated through modeling and in laboratory studies that smallmouth bass survival to later year classes is contingent on growing large enough by their first fall to sustain them through the winter.…”