Caracterización preliminar de hábitats y megafauna en caladeros de cigala (Nephrops norvegicus) del golfo de Cádiz a partir de imágenes submarinas

Abstract

Underwater images, sediment samples and CTD measurements were taken in Norway lobster (Nephrops norvegicus) fishing grounds of the outer shelf and upperslope of the Spanish margin of the Gulf of Cádiz for characterizing habitats, megafauna and spatial relationships with environmental variables. A total of 58 taxa and 8 habitats were recorded, being sea-pen communities on muddy sediments the most widespread. Depth, sediment type and bioturbation are the most influencing variables on the spatial distribution of the habitats and associated megafauna. Densities of some habitat forming species (e.g. Kophobelemnon stelliferum) were lower or similar to those previously found in mud volcanoes located in the area, which should be restricted to trawling activities. Nevertheless, habitat forming species display low densities in areas with dense populations of N. norvegicus and high bioturbation, probably caused by lobster sediment removilization and predation, therefore these areas should continue to be destined to trawling activities.