EVIDENCE OF INTERACTIONS BETWEEN WALLEYE AND YELLOW PERCH IN NEW-YORK-STATE LAKES

We believe that the population dynamics of walleye (Stizostedion vitre um vitreum) and yellow perch (Perca flavescens) are strongly affected by biotic interactions: abundant walleye populations limit perch recru itment, resulting in fast perch and slow walleye growth rates; sparse walleye populations allow for strong perch recruitment resulting in sl ow yellow perch and fast walleye growth rates. If these mechanisms are important, we would expect a negative correlation between perch and w alleye growth rates. Mean length at age 4 for walleye and yellow perch in 23 New York waters were negatively correlated. Further, changes ov er time in length at age of both species as walleye populations increa sed in Canadarago and Silver Lakes follow the regression from the whol e data set. This indicates a strong interaction between these two perc id species in New York waters. The residuals were affected by lake pro ductivity, but not lake area or mean depth. Waters with very low produ ctivity had smaller walleye and yellow perch than expected from the re gression.