Data from: Influence of environmental parameters on movements and habitat utilization of humpback whales in the Madagascar breeding ground

Assessing the movement patterns and key habitat features of breeding humpback whales is a prerequisite for the conservation management of this philopatric species. To investigate the interactions between humpback whale movements and environmental conditions off Madagascar, we deployed twenty-five satellite tags in the northeast and southwest coast of Madagascar. For each recorded position, we collated estimates of environmental variables and computed two behavioral metrics: behavioral state of ‘transiting’ (consistent/directional) vs ‘localized’ (variable/non directional), and active swimming speed (i.e. speed relative to the current). On coastal habitats (i.e. bathymetry < 200 m and in adjacent areas), females showed localized behavior in deep water (191 ± 20 m) and at large distances (14 ± 0.6 km) from shore, suggesting that their breeding habitat extends beyond the shallowest waters available close to the coastline. Males’ active swimming speed decreased in shallow waters, but environmental parameters did not influence their likelihood to exhibit localized movements, which was probably dominated by social factors instead. In oceanic habitats, both males and females showed localized behaviors in shallow waters and favored high chlorophyll-a concentrations. Active swim speed accounts for a large proportion to observed movement speed, however breeding humpback whales likely exploit prevailing ocean current to maximize displacement. This study provides evidences that coastal areas, generally subject to strong human pressure, remain the core habitat of humpback whales off Madagascar. Our results expend the knowledge of humpback whale habitat use in oceanic habitat and response to variability of environmental factors such as oceanic current and chlorophyll level.