Sexual Dimorphism in Body Size and Form in Yellow Perch

Sexual dimorphism is a base and is relational for sex control and development of monosex aquaculture species. In the present work, sexual dimorphism of morphometrics, specifically body size and form, of yellow perch (Perca flavescens) has been studied. Three different types of culture conditions, including ponds, indoor and outdoor tanks, were utilized to investigate the sexual size dimorphism. Two hundred yellow perch individuals from tanks, ponds, and a lake were collected, and their sexual dimorphism in shape was analyzed based on principal components and discriminant analysis. Yellow perch display female-biased sexual dimorphism (e.g., females grow faster and gain larger size than males). We found that females exhibited significantly larger size than males (P < 0.01) when female body weight (BW) ranged from 65.4–89.1 g (total length (TL) ranged from 16.8–18.5 cm) and male BW ranged 50.9–68.1 g (TL ranged from 15.6–17.1 cm). The most obvious morphological differences between females and males were found in the posterior trunk region, especially in the caudal peduncle of the fish. The standardized canonical discriminant function and Fisher's linear discriminant function were established on the basis of the analysis in morphology difference. The functions provided important and informative variables to differentiate male and female individuals. The method established is an effective tool to identify female and male yellow perch, which could aid sex control, effective breeding management, and precise experiments in this species.