Importance of Coarse Woody Habitat Complexity to Yellow Perch Egg Skein Deposition and Survival

Abstract

Habitat introductions are often implemented in aquatic systems to meet fishery management goals. Conifer trees have been used to augment spawning habitat for Yellow Perch Perca flavescens to support and suspend their unique egg skeins above the lake bottom in hopes of increasing reproduction and recruitment; however, little is known about the influence of tree characteristics on the reproductive success of Yellow Perch. Our objective was to evaluate the effects of tree complexity on the skein deposition and survival rates of Yellow Perch. In February 2020, 30 eastern red cedar Juniperus virginiana trees were manipulated to one of five complexities (from 1 = least complex [all branches removed] to 5 = most complex [all branches retained]; n = 6 per complexity) and placed on the ice. After ice-off and tree submersion, we conducted snorkeling surveys every 2 d from March 31 to May 5, 2020, and recorded the number and viability of the skeins. We observed 35 Yellow Perch egg skeins. Yellow Perch preferred to deposit their egg skeins on tree complexities 4 and 5, whereas deposition on tree complexities 1, 2, and 3 was random. The nest survival models estimated that skeins that were deposited on tree complexities 1, 2, and 5 had a 27-d survival estimate of 0.07 (95% CI = 0.06 to 0.08) that was lower (β = −1.29; 95% CI = −2.32 to −0.27) than that for skeins that were deposited on complexities 3 and 4, with a survival estimate of 0.48 (95% CI = 0.43 to 0.52). Our results indicate that Yellow Perch prefer to deposit their egg skeins on intermediate cedar tree complexities that resulted in increased skein deposition and survival. Given our results, once introduced trees have deteriorated below an intermediate complexity, managers should consider supplemental introductions of more complex trees that benefit the reproduction of Yellow Perch.