Quantifying inter-population variability in yellow perch sexual size dimorphism

Abstract

Size-selective angler behavior or the implementation of length-based regulations may have implications in harvest-oriented yellow perch (Perca flavescens) fisheries where perch populations may display sexual size dimorphism (SSD), even though the occurrence of SSD remains poorly documented. Predicted and observed mean lengths-at-age were used to describe the occurrence of yellow perch SSD in populations from four states and one Canadian province. In addition, abiotic and biotic variables were used to predict the occurrence of SSD in yellow perch populations. Predicted mean lengths-at-age were significantly greater for female yellow perch after age 3 indicating female-biased SSD (higher female growth rates and greater maximum attainable lengths) occurred upon maturity. Using observed mean lengths-at-age, 85% of the study populations had at least 1 year class where females were significantly larger than males. Femalebiased SSD was present in almost two-thirds of the individual observed mean length-at-age year class comparisons. SSD could not be reliably predicted using yellow perch population dynamics or lake morphometry. Although, yellow perch SSD was positively correlated with lake productivity, a low fit statistic suggests a poor predictive relationship. This study has demonstrated the prevalence of female-biased SSD in yellow perch populations. Because yellow perch anglers are size selective and harvest oriented, the occurrence of female-biased SSD in a perch population will likely result in female-biased exploitation and, therefore, we recommend natural resource agencies collect age and gender-specific data to identify the occurrence of SSD in perch populations.

Sex-specific Changes in Walleye Abundance, Size Structure and Harvest Following Implementation of Regulation to Protect Broodstock

“…Letters indicates that means are significantly different at the P # 0.10 level. and attain greater lengths than males (Schoenebeck and Brown 2011;Uphoff and Schoenebeck 2012). The HSO regulation was designed to protect female walleye broodstock, and it has been successful in doing so, but because the population exhibits female-biased sexual size dimorphism males were not afforded the same protection.…”

Gill net selectivity of yellow perch

“…Male and female median and average lengths were the same or similar for mesh sizes 32, 38, and 46 where the numbers of both sexes appeared statistically large enough to discern sexual differences. Thus, it appears that, despite the known dimorphic differences in growth (Purchase et al 2005;Uphoff & Schoenebeck 2013), any potential morphometric differences were not apparent in similar-sized fishes, regardless of sex.…”

Population Characteristics of Yellow Perch in Dead Lake, Florida

“…In Dead Lake, female Yellow Perch experience faster growth in all age groups compared with males. Sexspecific growth rates occurs in many fish species (e.g., Suwannee Bass Micropterus notius [Bonvechio et al 2005], Largemouth Bass M. salmoides [Schramm andSmith 1988, Walleye Sander vitreus [Henderson et al 2003]), including Yellow Perch (Uphoff and Schoenebeck 2012) and is usually related to spawning activities. However, Schoenebeck and Brown (2012) suggest sexspecific growth rates may result from other anaerobic activities (e.g., foraging for prey and predator avoidance) coupled with spawning activities of male Yellow Perch.…”