North Temperate Lakes

At the North Temperate Lakes LTER site, we have observed cyclic dynamics in a population of yellow perch in oligotrophic Crystal Lake. Since 1981, we have observed 3 cases of cohort dominance in which two age-classes dominated the population for roughly 5 years. Across years, the presence of young-of-the-year fish was negatively related to juvenile perch abundance and positively related to adult perch abundance. Conclusions drawn from a statistical dynamic linear model suggest that oscillations in young-of-the-year perch abundance were intrinsically driven by the positive effect of adult perch reproduction and the negative effect of juvenile perch via cannibalism and competition ....