Populations of Commercial Molluscs within a Highly Biodiverse Marine Protected Area of the Northern Alboran Sea (W Mediterranean): Preferential Habitats, Seasonal Dynamics and Importance for Artisanal Fisheries

Seasonal dynamics and preferential sedimentary habitats of commercial molluscs have been studied in soft bottoms within the limits of the Special Area of Conservation (SAC) “Calahonda” (S Spain). This SAC harbours a high diversity of invertebrate communities, and it is located in a very touristy area of the littoral of Malaga and within the limits of one of the most productive shellfish fishing areas of the NW Alboran Sea. Here, the artisanal fishery targeting molluscs is a locally important activity because some species (e.g. Chamelea gallina, Callista chione, Donax trunculus) are highly demanded by locals and tourists and therefore reaching high commercial value. More than 200 molluscan species inhabit the soft bottoms of the SAC “Calahonda”, from which eight species collected in this study have economic value. The bivalve C. gallina was the most abundant and frequent commercial species, mainly at shallow fine and medium sand bottoms, followed by C. chione at coarse sand bottoms. Some species displayed higher abundance values of large or small size individuals at different depths, and most of them showed maximum abundances in spring and summer. Many invertebrate species associated with these soft bottoms are potentially very sensitive to dredging activities, especially echinoderms, decapods and cnidarians. Further research regarding the potential impact of fisheries on these assemblages would be desirable, especially considering the high biodiversity existing within this SAC and the increase of tourists in the last years.