On the biology and fishery of Aristeus antennatus (Risso, 1816), (Decapoda, Dendrobranchiata) in the Ibiza Channel (Balearic Islands, Spain)

This study presents data on the biology and fishery of Aristeus antennatus in the Ibiza Channel, obtained from monthly samples carried out on commercial catches landed in the port of Santa Pola during 1992, 1993 and 1994. The estimations undertaken from the von Bertalanffy Growth Model (VBGF) parameters gave high K values, indicating that the males would reach 23 mm CL in the first year and the females 29 mm CL, which would represent a maximum life expectancy of three and four years, respectively. The reproduction period. based on the percentages of maturation, fecundity and spawning activity, was defined as starting at the end of the spring and lasting through the summer, with greatest intensity in the months of June to September. The sizes at first maturity (L-50) of 18.1 mm for males and 21.9 mm for females, indicated that maturation would have to take place within the first year of life. The total annual landings for the whole zone fluctuated around an average of 76 t per year. The mean catch per unit of effort (CPUE), expressed in kilograms of shrimp by boat and fishing day, was 29.12 kg/boat/day. The values of biomass, yields and mortalities obtained by LCA and VPA showed that the stock was slightly overexploited, although the resource was able to cope with variations in the fishing effort with the yields hardly altering. This demonstrated a high rate of biomass production (Turnover), with the mortality vector having a greater effect on the older age classes, especially in the females. This fact could be due to the whole resource not being equally accessible, since exploitation was based on the largess sizes, in which the females predominated.