Habitat, distribution, and abundance of the commercial octopus (Octopus insularis) in a tropical oceanic island, Brazil: Information for management of an artisanal fishery inside a marine protected area

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The spatial distribution, abundance and habitat of a population of a shallow-water octopus, Octopus insularis, subject to some fishery pressure, was studied in the Fernando de Noronha Archipelago, a marine protected area off northeastern Brazil. Three techniques were used: visual censuses in fixed quadrants and in roving-diver and catch per unit of effort (CPUE) of the commercial fishery. We had two hypotheses, that the species had a nonrandom distribution, related to substrate and body size, and that relative abundance outside the national park would be lower than within, possibly due to fishery pressure. We found a patchy distribution over all, with octopuses almost confined to substrates with a large proportion of hard surfaces. There were seasonal and depth effects on distribution of the very small octopuses found mainly in shallow water (intertidal to 5 m depth) during the dry season. Abundance was similar inside and outside of the national park, which suggests that the octopus fishery is not a threat to the abundance of O. insularis at this present level