Pautes de distribució de les espècies de la família Portunidae (Crustacea: Brachyura) al fons de substrat tou de la Mediterrània nord-occidental

Abstract

The distribution patterns of the different species of portunid crabs occurring on soft substrates off the Catalan coasts have been studied from data gathered during fishery research surveys. A total of eight species were recorded: Carcinus mediterraneus, Liocarcinus depurator, Liocarcinus maculatus, Liocarcinus puber, Liocarcinus vernalis, Liocarcinus arcuatus, Macropipus tuberculatus, and Portunus hastatus. The study has concentrated on the three most common and abundant species: L. vernalis, L. Depurator and M. tuberculatus. L. vernalis was most abundant on sandy substrates on the shallow continental shelf, whereas L. Depurator was mainly found on muddy substrates of the continental shelf, with low densities on the slope. M. tuberculatus occurred mainly on the muddy bottoms of the upper slope and lower shelf. The proportion of males increased with depth in L. Vernalis. In L. Depurator, the highest proportions of females were found on the upper slope, as happened in M. tuberculatus. In the latter, the proportion of males was highest in the shallowest and deepest areas of the depth distribution range of the species. Recruitment occurred preferentially in the shallowest depths inhabited by L. Vernalis and L. Depurator. In M. tuberculatus, it occurred on the upper slope, with the largest sizes being found in the shallowest areas inhabited by the species.