Killer whales habitat suitability in the Iberian Peninsula and the Gulf of Biscay: Implications for conservation

Abstract

This study addresses existing gaps in our understanding of the ecology of killer whales by investigating their habitat use dynamics in the Atlantic coastal waters of North Africa, the Iberian Peninsula, and the Gulf of Biscay. Despite previous research on their distribution during the Atlantic Bluefin tuna migration in the Strait of Gibraltar and adjacent waters, substantial knowledge gaps persist, particularly regarding their movement patterns beyond these regions and seasonal variations in habitat use. Utilizing killer whale occurrence records from 2020 to 2023 and considering environmental factors influencing prey presence, we employed seasonal spatial distribution models. MaxEnt models exhibited robust predictive performance, emphasizing distance to shore, depth, and sea surface temperature as key factors influencing killer whale habitat suitability. Spatial distribution patterns reveal a peak in coastal waters of the southern Iberian Peninsula and North Africa during winter and spring, with a significant shift northward and expansion during summer and autumn towards the Gulf of Biscay. This expansion suggests a broader distribution of killer whales in the Northeast Atlantic during warmer months, encompassing a diverse range of habitats. The research underscores a substantial interaction (47%) between killer whales and recreational vessels, posing concerns for both the killer whales and maritime safety. This study provides valuable insights on killer whale habitat use in the Atlantic waters from North Africa to the Gulf of Biscay, thereby supporting conservation and management efforts in the region.