Global climate changes over time shaping the environmental niche distribution of Octopus insularis (Cephalopoda: Octopodidae) in the Atlantic Ocean

In the Atlantic Ocean, Octopus insularis Leite and Haimovici, 2008 inhabits warm and shallow habitats, where it is one of the main targets of cephalopod fisheries. Considering the current trend of increase of increasing sea-water temperature, warm-water species are expected to expand their geographic distribution range. Ecological niche modeling (ENM) is an important tool to help describe likely changes in geographic distribution patterns of a species in many climatic scenarios. To evaluate the changes of O. insularis distribution over time, the Maximum Entropy approach was used, which estimated a suitable climatic niche for Octopus under five scenarios of global climate changes. Six environmental layers were chosen to model the modern suitable climatic niche of O. insularis and four variables were used for past and future scenarios. The ENM in different climatic scenarios showed good validation and pointed out an increase of the suitable niche for O. insularis settlement, from Last Glacial Maximum (21 Kya) up to future scenarios. In the future projections, the availability of species suitable niche will potentially increase in Tropical Atlantic compared to the current distribution. In addition, the modeling pointed out the possibility of an expansion from the species current range to Temperate Northern Atlantic, Temperate South America, and Temperate South Africa. This may cause potential threats, such as possible extinction of endemic species, habitat displacement of native octopuses, reorganizations in the trophic chain.