Global climate changes over time shape the environmental niche distribution of Octopus insularis in the Atlantic Ocean

Abstract

In the Atlantic Ocean, Octopus insularis (Cephalopoda: Octopodidae) 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 increasing seawater temperature, warm-water species are expected to expand their geographic distribution ranges. Ecological niche modeling (ENM) is an important tool to help describe likely changes in geographic distribution patterns of a species in different climatic scenarios. To evaluate changes in the distribution of Octopus insularis over time, the maximum entropy approach was used, which estimated a suitable climatic niche for Octopus under 5 scenarios of global climate change. Four environmental variables were chosen to model the suitable climatic niche of O. insularis in the present, 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 the Last Glacial Maximum (21 kya) up to future scenarios. In the future projections, suitable niche space will potentially increase in the tropical Atlantic compared to the current distribution. Modeling pointed out the possibility of expansion from the current range of the species to the 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, and reorganizations in the trophic chain.