Sexual dichromatism and dimorphism in the goatfish Parupeneus spilurus (Perciformes: Mullidae) in southern Japan

Abstract

Examination of gonads, fresh coloration and external morphology of Parupeneus spilurus (Perciformes: Mullidae), based on 55 males [115.4–315.9 mm SL (mean 254.1 mm)] and 22 females [116.2–299.5 mm SL (225.3 mm)], provided evidence of both sexual dichromatism and dimorphism. Males consistently had six to nine oblique yellow stripes and two yellow stripes on the second dorsal fin and anal fin, respectively. Females less than 212.3 mm SL had a reddish second dorsal fin, becoming yellowish (but no stripes or blotches) with maturity (> 215.4 mm SL). The anal fin of females was usually reddish without yellow stripes, even at full maturity, although a single yellow stripe on the anal fin is likely during breeding periods (at least before ovulation). Whereas the caudal fin of females always lacked yellow markings, these occurred in mature males (> 193.0 mm SL), tending to change from stripes to blotches via broken stripes with subsequent growth. Males differed slightly from females in some relative proportions (orbit diameter, and upper-jaw and anal-fin base lengths). Parupeneus spilurus was found to be a gonochoristic, multiple-spawning species (more than one spawning per year) with asynchronous ovarian development.