To what degree do preferred prey abundance and temperature influence growth rates of larval yellow perch in Lake Erie?
The Ohio State University
Growth during the larval stage can have important effects on future foraging and growth performance, as well as subsequent survival and recruitment to the fishable population. Preferred prey abundance and temperature have both been shown to influence larval fish growth in a variety of ecosystems. Toward improving our understanding of how these factors influence larval yellow perch (Perca flavescens) growth in Lake Erie, I examined the relationship between temperature, ambient zooplankton abundance, and larval yellow perch diets and growth rates in Sandusky Bay (Ohio) during 1994–1998, 2017, and 2018. I hypothesized that both preferred prey abundance and temperature would enhance the growth of larvae. Using linear modeling, I found that preferred zooplankton prey availability was unrelated to larval yellow perch growth (cyclopoid: t = 3.90, p = 0.06; calanoid: t = 1.06, p = 0.40), which was unexpected. Similarly, temperature during the time when larval yellow perch were caught was unrelated to growth (t = -3.80, p = 0.06). Furthermore, while mean April temperature (an indicator of the spring thermal conditions) was related to larval yellow perch growth rate, this relationship was unexpectedly negative (t = -5.14, p = 0.04). Because I am uncertain of why my expectations were not borne out, I recommend future research to evaluate other metrics of spring and prior winter conditions (e.g., overwinter ice-cover, winter degree days for adult yellow perch, spring onset, spring degree days) to identify the mechanisms influencing larval yellow perch growth.
Aquatic ecology, Early life history, Zooplanktivory, Climate change, Prey selectivity, Fish recruitment