Estimación del nivel óptimo de mortalidad por pesca y riesgo de sobreexplotación de la castañeta (Cheilodactylus bergi)

Abstract

Patagonian scallop (Zygochlamys patagonica King & Broderip, 1832): A new fishery in the Argentine continental shelf. Yield-per-recruit model was applied to the stock of castañeta (Cheilodactylus bergi)in the Argentine-Uruguayan Common Fishing Zone (Southwest Atlantic, among 34° and 39°30' S), in order to estimate the range of F0.1 values resulting from the uncertainty in the parameters of the model. Simulations with variations in natural mortality and recruitment were carried out, in order to estimate the risk of overfishing associated with different fishing mortality levels. The criterion that spawning stock biomass be mantained over 35. of its unexploited level was adopted. For an optimum age of first capture of 4 years, the range of calculated F0.1 values was of 0.17 to 0.35 with a mean value of 0.25. The risk of overfishing associated with this range was between 0 and 9. for a 60. random variation in recruitment. It is recommended that initial levels of fishing mortality do not exceed 0.25, in order to minimize the risk of recruitment overfishing. Caution is advisable because of the difficulty to anticipate the impact of the fishery on a recently exploited population with overfishing antecedents, and because of the unknown stock-recruitment relationship, which is fundamental to define rightly the critical spawning stock biomass level.