Growth and distribution of Solenocera membranacea (Risso, 1816) (Decapoda: Dendrobranchiata) in the northwestern Mediterranean Sea
Montserrat Demestre, Pere Abelló
The shrimp Solenocera membranacea occurs on muddy and sandy-muddy bottoms on the continental shelf and slope of the Mediterranean and northeastern Atlantic. Its main concentrations are localised on the upper slope (200-500 m). A significant trend was found in both male and female sizes to increase with increasing depth. This species shows a marked sexual size dimorphism. Sizes of males ranged between ll and 21 mm carapace length, whereas females ranged between 10 and 30 mm. Cohort analysis of the size frequency distributions suggests the occurrence of two recruitment periods in the study area in a year. The method of Bhattacharya was used to estimate the number and mean size of each normally distributed group of sizes within each quarterly polymodal size frequency distribution. The von Bertalanffy growth parameters have also been estimated. The growth patterns are different for the two sexes. The maximum asymptotic length is markedly higher in females. The growth coefficient shows intermediate characteristics between those of shallow-water and deep-sea penaeid shrimps.