Notes on the Biology of the Portunid Crab, Portunus sanguinolentus (Herbst), in Subtropical Queensland Waters

Abstract

Trawl-caught Portunus sanguinolentus were more abundant in oceanic than estuarine waters in south- east Queensland. In samples, males outnumbered females by 1.7 : 1. Males attained a larger size than females and, for a given carapace width, weighed more than females. The smallest sexually mature male and female crabs had carapace widths of 83 and 74 mm respectively. Crabs recruited to the sampled population throughout most of the year except during winter, when moulting activity was also limited. April-May was a major mating period, and it is postulated that mature female crabs moved into deeper oceanic water to spawn.