Distribution and abundance of postlarvae and juveniles of shrimps of the genus Penaeus in Kino Bay and La Cruz lagoon, Sonora, Mexico

Abstract

Samplings with plankton net, cast net and otter trawl were made every two weeks to estimate the distribution and abundance of Penaeus shrimp postlarvae and juveniles in Kino Bay (IX/89-IX/90) and La Cruz coastal lagoon (VII/89-IV/91), Sonora, Mexico. The postlarvae were present from June to November, with maximum average abundance in July 1990: 220.58 postlarvae/10 m³ in La Cruz and 72.5 postlarvae/10 m³ in Kino Bay. Penaeus califoniensis was the most dominant species. There was no statistical evidence of postlarva aggregation at the sampling stations. Only juveniles of P. califoniensis (brown shrimp) and P. stylirostris (blue shrimp) were caught, dominating the first. The maximum total length of juveniles was 13 cm (brown shrimp) and 16 cm (blue shrimp). From length data, we believe that brown shrimp enter La Cruz at an earlier developmental stage than blue shrimp.