The inter‐annual fishing variability in Octopus insularis (Leite & Haimovici 2008) as a result of oceanographic factors

Abstract

AbstractOctopus insularis, despite being widely fished from Brazil to Mexico, has only recently been described as a different species from the sympatric Octopus vulgaris complex in the tropical Atlantic, where its occurrence is determined by different environmental factors. Using a 10‐year time series from Brazil, we modeled how topographic aspects and oceanographic variables affected the landings of O. insularis. For that we used a locally weighted scatterplot smoothing (LOESS) technique and residual autocovariate‐boosted regression trees (RAC‐BRTs). In addition to the octopus landing per unit effort (LPUE) being driven by the seafloor structure, we also observed that it was directly related to the temperature and inversely related to chlorophyll. Higher LPUEs were observed in warmer years. Although the relationship between LPUE and chlorophyll or temperature has not yet been explained under laboratorial conditions, the higher catches observed at higher temperatures may be both a result of the local fishing dynamics and a warning toward the possibility of future niche expansion, due to climate change. If the latter is confirmed, octopus fisheries in parts of the South Atlantic would need to adapt to a smaller, and thus cheaper, body‐sized species.