Abundance and size frequency of postlarvae of <i>Penaeus occidentalis</i> in the Gulf of Nicoya, Costa Rica

Abstract

Postlarvae of Ihe Genus Penaeus were collected once a month from November/94 to April/95 at Cocoroca beach in the Gulf of Nicoya. Costa Rica. They were idemified morphologically. and those of P. occidentalis were studied. It wa." revealed tha! the postlarvae: of P. occidentalis occupied 65.6 % of the total individual s collected, and 24.1 · 94.9% of the monthly composition. and their distribution density varied from 0.7·5.8 individuals/m2. The carapace length(CL) of lhe posllarvae of P. occidentalis ranged from 1.55 10 9.58 mm, which suggested a migratory siz.e of them. The frequency of the CL showed a skewed distribution, which suggested a migratory pattem of lhe postlarvae of tha! species. 1ñe relative growths of the 6th abdominal somite and the carpus of the third pereopod of the postlarvae of P. occidentalis were a1so examined against the CL.