<b> Reproductive pattern, size at first maturity and stock-recruitment relationships of the Argentine stiletto shrimp ( <i>Artemesia longinaris, </i>Decapoda: Penaeidae) in southern Brazil </b>

Abstract

Artemesia longinaris has been recently exploited by commercial and artisanal fisheries in Southern Brazil. To investigate the reproductive biology of this species, monthly samples were analyzed between February/2002 and January/2003, in depths between 5 and 20 meters in surrounding area of the Barra do Rio Grande. Stock-recruitment relationships (SRR) were estimated, as well as a preliminary predictive model for recruit biomass. Reproductive effort is concentrated in spring; however, recruitment was observed year round. Reproduction in autumn is more variable, and susceptible to intense rainfall and consequent low salinity observed in the studied area. A reproductive migration to depths farther than 15 meters was observed, and recruitment in shallower waters starts approximately one month after hatching. Mean length at first maturity was estimated in 16.76 mm and is achieved in approximately 4 months. Significant fit of stock-recruitment relationships (SRR) was observed for three models tested under adverse environmental conditions, suggesting that the reduction of spawning biomass combined with unfavorable environmental conditions may lead to recruitment overfishing. A preliminary predictive model was developed and the main factor influencing recruitment of the species is salinity in spawning season. The main factor influencing recruitment success under adverse environmental conditions is the biomass of spawning stock, while under favorable conditions salinity in spawning season plays a significant role.