Evidence of predatory control of yellow perch (Perca flavescens) recruitment in Lake Erie, U.S.A.

Abstract

Predation can be a major factor in recruitment success of yellow perch (Perca flavescens Mitchitl). Trawl catches of age‐0 yellow perch in western Lake Erie declined from 870·3 per trawling h in June to 3·3 per trawling h in late July 1988. Coincident with the decline in relative abundance of age‐0 yellow perch we found large numbers of age‐0 yellow perch in the stomachs of small walleyes (Stizostedion vitreum Mitchill). From this evidence we hypothesized that predation by walleyes may have caused the demise of the 1988 year‐class of yellow perch. We used a population and bioenergetics modelling approach to estimate the impact of walleye predation on the abundance of age‐0 yellow perch. Modelling showed that 6·8 × 109 age‐0 yellow perch that had attained 18 mm total length (t.l.), were eaten by small (age‐2 and younger) walleye from June through July 1988. We estimated that walleye ate 28·4–89·7% of the yellow perch reaching 18 mm t.l. during 1988. The majority of this predation (77% of total) was by the abundant age‐2 cohort of walleyes. We concluded that, even in a large system such as Lake Erie, predation can play a major role in structuring year‐class strength of yellow perch and, thus, management of percid fisheries should be conducted on a fish‐community basis.