Modelling cetacean distribution and mapping overlap with fisheries in the northeast Atlantic

Abstract

Improving our knowledge of cetacean distribution and habitat use are key if we are to effectively ensure good conservation status for these species. Often however, sufficient data are lacking, inhibiting conservation efforts of many species. This study aims to combine historical datasets to generate habitat suitability models and thus maps, for eight species of cetacean regularly sighted in the Irish portion of the northeast Atlantic; fin whale, minke whale, pilot whale, sperm whale, white-sided dolphin, bottlenose dolphin, Risso's dolphin and white-beaked dolphin. Habitat suitability models were developed using MaxEnt modelling software for a range of environmental factors; sea-surface temperature, mixed layer depth, depth, slope, chlorophyll a concentration, sea surface salinity, distance to the 200 m contour. We predicted species exposure to fishing gears by integrating habitat suitability models with information on fishing vessel activities within the study area. The main predictors of habitat suitability for all species were topographic variables, particularly depth and slope, highlighted by two areas of high species richness around areas of topographic heterogeneity, along the continental shelf and on the west coast. Combining habitat models with fishing activity, indicated areas of high exposure off the north and south coasts and in an area known as the Porcupine Bank off the west coast. These results are valuable for conservation and management of cetaceans and fisheries in the study area. Methods can be easily adjusted to allow replication for other species and other anthropogenic activities. We recommend future effort focuses on winter months to fill in the gaps on year round cetacean distribution.