Cephalopods in the upwelling-influenced transition zone of Arraial do Cabo, Brazil, SW Atlantic: diversity, habitat use and sustainable management implications

Despite the important role of cephalopods in demersal and pelagic trophic webs and their economic value as a fishing resource, they are still an understudied group in regional and local scales. Here, we evaluate the diversity of cephalopods in subtropical rocky reefs in Arraial do Cabo, a major upwelling region in southeastern Brazil, reporting information on distribution, habitat use, oceanographic conditions and biogeography. Using data obtained from underwater surveys, artisanal fisheries monitoring, citizen science and social media, a total of 15 species were identified, including three new records for the region and one new record for the Brazilian Province. Overall, the cephalopod fauna of Arraial do Cabo exhibited a mixture of warm- and cold-water species, as well as neritic and oceanic taxa. The co-occurrence of so many cephalopods in such a geographically limited area was mostly explained by the variety of bottom substrates and live covers. Thus, the combination of this feature with different sets of thermal and oceanographic conditions increases the habitat heterogeneity, probably accommodating octopus and squid species with diverse environmental preferences and tolerances.