Composition and distribution of the larval decapod community in the deep sea of the Western Mediterranean Sea Balearic Sub‐basin

Abstract

Mechanisms facilitating larvae transport from continental to more oceanic areas were investigated in the Balearic sub‐basin (BSB), Western Mediterranean Sea. The abundance, distribution, and development stages of decapod larvae were recorded for a transect of 28 stations crossing the central eddy of the BSB. Zooplankton samples were taken to 1,800 m depth by horizontal and oblique 500‐µm mesh size nets hauls towed near the benthic boundary (BBL) and in deep scattering layers (DSL). In total, 67 taxa belonging to Decapoda and one Stomatopoda were identified. Advanced development represented 75% of the individuals recorded. 75% of the species corresponded to adults of deep‐sea species, 9% were sergestids (mesopelagic species), and the remaining 16% corresponded to shelf and coastal species. Cluster assemblages formed were related to the hydrological conditions, water masses dynamics, and geomorphologic structures mainly associated with nepheloid layers. Advanced and juvenile specimens of commercial species such as Parapenaeus longirostris, Geryon longipes, and Aristeus antennatus were found close to seafloor BBL. The influence of trophic ecology should be considered as the priority factor of larvae concentrations in deep.

Larvae of the blue crab Callinectes sapidus Rathbun, 1896 (Decapoda: Brachyura: Portunidae) in the Balearic Archipelago (NW Mediterranean Sea)

“…2). The second larva, captured in October 2011, was also identified as a megalopa, although neither biological nor biometric information was obtained (Carbonell et al 2021). Both specimens were clearly identified by their pointed rostrum with the horizontal placement of the rostral spine, the abdominal pleopods, the appearance of chelae and the cornua project from the posterior edge of cephalothorax (Costlow and Bookhout 1959).…”

“…The second survey was performed within the project ANTROMARE (CTM2009-12214-C02-01/ MAR), in October 2011, by sampling 28 stations throughout the Balearic sub-basin, from the Catalonian coast to the Balearic Archipelago. Four zooplankton samples were taken at midwater through oblique hauls with a 500 μm mesh WP2 net (Carbonell et al 2021).…”

Genetic Variability and Connectivity in the Western Mediterranean Populations of the Bathyal Crab Geryon longipes

“…G. longipes is often commercialised as a demersal trawling bycatch of the red shrimp fishery in the Western Mediterranean ports [32]. While its larval morphology has been described [33], information concerning the depths of its larval occurrence or its behaviour and dispersion is still scarce [34,35]. Concerning other geryonid species, information on this subject is also scarce, but it shows that the first larval stages are also epipelagic [34,36,37] and that early-stage larvae show physiological and behavioural mechanisms that allow them to ascend in the water column, while late stages descend into deep waters [8].…”