Distribution and Biological Features of Munida perarmata A. Milne-Edwards & Bouvier, 1894 in the Western Mediterranean

VIII International Symposium on Marine Sciences, 6-8 July 2022, Las Palmas de Gran Canaria, España

Munida perarmata is a decapod crustacean that dwells on mud bottoms from the intermediate continental slope to the bathyal depths (near 2000 m). It shares habitat with other species such as the red shrimp Aristeus antennatus, an important trawling objective (Abelló et al., 2002) (Macpherson & García, 2008). Due to its limited abundance and habitat conditions, it is a species whose population characteristics are relatively unknown. It is for this reason that this study intends to acquire a greater knowledge about the geographical and bathymetric distribution, and the interannual variability of its populations by means of data obtained in pluriannual sampling executed during 25 years in the western Mediterranean (MEDITS Program) (Spedicato et al., 2019; Bertrand et al., 2002), and present the main biological characteristics by means of additional sampling from other campaigns. The obtained results have allowed to detect a population decline, specially pronounced in the last decade. The species is scarce in the Alborán Sea, while in the Catalan-Balear basin is abundant but smaller in size. Females perform an ontogenetic migration as they mature sexually towards shallower depths, to spawn near 500 m. The CL (carapace length) average is 16.7 mm, and there are no differences between sexes. The estimated sexual maturity size calculated by means of the relation between RCL (Right Cheliped Length) and CL, is 14 mm of CL. Bigger individuals dwell between 400 – 500 m and near 1200 m, while juveniles live between 800 and 1000 m. Males and females follow the same bathymetric distribution. This type of distribution might indicate that the recruitment occurs on the inferior limit of the twilight zone (near 1000 m), and that the individuals perform an ontogenetic migration towards shallower or greater depths depending on differences in its coloration, caused by the differences in depredation pressures above and below the twilight zone (Aguzzi et al., 2013). All the information collected in this study will bring the opportunity to know better the biology of continental slope and bathyal depth species

Peer reviewed