AUTHORS: Andrew Foley, The Ohio State University; Jim Hood, The Ohio State University; Lindsey Bruckerhoff, The Ohio State University; Stuart Ludsin, The Ohio State University
ABSTRACT: Lake Erie fisheries are a unique case study of conservation interest as many surrounding agencies are focused on understanding their population dynamics. Within the lake, sportfish populations vary in response to human-driven environmental change, including climate change, altered nutrient inputs, and invasive species. Understanding how these ecosystem changes impact fish during susceptible life stages is vital to maintaining healthy fish stocks. While the exact mechanisms interacting with these fisheries have generally remained elusive, processes operating during early life stages (e.g., egg, larval, and juvenile) are thought to be the primary driver of variability in recruitment to Lake Erie’s recreational and commercial fisheries. One population that has declined during the past decade for unknown reasons is central Lake Erie Yellow Perch (Perca flavescens), with no strong year-classes occurring since 2012. We hypothesized failed recruitment to the age-0 juvenile stage, is primarily due to recent increases in top predators, including invasive White Perch (Morone americana) and native Walleye (Sander vitreus), with zooplankton (prey) limitation during spring being of secondary importance. Fortunately, a wealth of long-term data exists from 2000-2023 on many biotic and abiotic mechanisms known to impact fish recruitment. To test our hypothesis, we analyzed data from multiple management agencies across a long time series and broad spatial scale to better understand fish recruitment during this time of management need. Using Generalized Additive Models, we tested the effects of zooplankton (prey) availability, temperature, predation pressure, river discharge, and hypoxia on Yellow Perch recruitment. Herein, we report findings from our modeling, which indicate recruitment and the processes driving it have varied through time as well as spatially across the central basin. We discuss the value of our research as a case study for understanding the long-term impacts of human-driven environmental change on recruitment using historical datasets and their application to fisheries management.
