Analysis of video recordings made during dives of the submersible “Nautile” in the Bay of Biscay, NE Atlantic Ocean, indicates that demersal fish species are associated with different marine habitat types. Four different dive transects were studied with respect to fishes, benthic invertebrates and associated environmental characteristics. A total of 480 fishes belonging to 19 taxa were ordinated by means of canonical correspondence analysis. Deep-sea epifauna was dominated by a diverse assemblage of suspension feeders indicating different gradients of vertical and horizontal current flow. Both biotic and abiotic factors influence fish habitat distribution. The most abundant fish the orange roughy (Hoplostethus atlanticus), showed a clear association with complex bottoms, including coral colonies. The false boarfish (Neocyttus helgae), occurred in habitats associated with strong currents, high slope inclination, and corals. Others such as roundnose grenadier (Coryphaenoides rupestris) and Kaup's arrowtooth eel (Synaphobranchus kaupii) occurred in a wider range of habitat types. Deep-sea destructive fishing methods, like trawling, should be banned in the areas of cold water corals and a network of no take zones should be introduced as a precautionary method of fisheries management.
Deep-sea conservation, Deep-sea ecology, Demersal fishes, Deep sea epifauna, Deep-sea image analysis, Submersibles