An Egg-Mass Census Method for Tracking Fluctuations in Yellow Perch (Perca flavescens) Populations
Extreme annual fluctuations among yellow perch (Perca flavescens) populations are common and have been related to changes in the physical environment during early stages of the development of a year-class. However, critical investigations of these relationships are often hampered by the lack of accurate techniques for estimating abundance. In this paper an egg-mass census technique is described, and statistical procedures which provide population estimates with confidence limits are given. Also discussed are results of preliminary investigations of environmental factors which may have a dramatic affect on the year-class strengths of perch. Winds play an important role in determining recruitment rates. Wind-generated internal seiches may result in thermal shocking of perch embryos which subsequently affects juvenile survival.