Does Anaerobic Activity Differ Seasonally or between Sexes in Yellow Perch Populations?

Abstract

AbstractAnaerobic activities, such as those associated with spawning, foraging for prey, and predator avoidance, may vary seasonally and by sex as energetic demands change. We quantified the glycolytic muscle enzyme lactate dehydrogenase (LDH) to determine whether enzyme concentrations differed seasonally or between sexes in yellow perch Perca flavescens populations that exhibited female‐biased sexual size dimorphism (SSD). Patterns in LDH for a yellow perch population with fast‐growing fish and one with slow‐growing fish varied significantly among seasons and between sexes. The LDH concentration was lower during spring than during summer and fall, indicating that activity costs associated with nonspawning burst‐swimming activities (e.g., foraging for prey or predator avoidance) are greater than costs associated with spawning activity. In addition, LDH concentrations were greater in males than in females for both populations. Therefore, we hypothesize that greater cumulative, year‐round anaerobic activity (rather than just spawning activity) by males is responsible for female‐biased SSD in yellow perch.