Distribution, Abundance, and Sexual Composition of Stomatopods in the Gulf of Nicoya, Costa Rica

Abstract

ABSTRACT Stomatopod Crustacea were collected by trawling in the Gulf of Nicoya on the Pacific Coast of Costa Rica. Abundances, size-frequency distributions, and sexual composition were measured at 12 stations. Eight stations in the upper, more estuarine regions of the Gulf were sampled monthly, while the 4 stations in the lower Gulf were sampled approximately weekly. Four species of Squilla were identified: S. parva Bigelow, S. aculeata Bigelow, S. mantoidea Bigelow, and S. panamensis Bigelow. However, only S. parva and S. aculeata were abundant at the stations sampled. Distribution and abundance differed between the two common species. Squilla parva was restricted to the lower Gulf, whereas S. aculeata was found both in the upper and lower Gulf. In contrast to S. parva, S. aculeata was significantly more abundant in the upper Gulf than in the lower Gulf. In both species the population was dominated by females. Nevertheless, the relative abundance of males of S. aculeata varied with location in the Gulf. Size distribution of both species varied significantly among months. Although the population was dominated by larger individuals, juveniles were frequent during most of the year.