MEPS 718:119-136 (2023)  -  DOI: https://doi.org/10.3354/meps14374

ABSTRACT: Habitat use of the northern bottlenose whale Hyperoodon ampullatus in the Northeast Atlantic is poorly understood. This study aimed to identify locally utilised habitat features and create predictions of northern bottlenose whale habitat use over a wider area around the island of Jan Mayen, Norway. Bottlenose whales were sighted regularly near Jan Mayen in June 2014-2016 at higher rates than over a wider study region reported in other studies, indicating that the Jan Mayen habitat may be a hotspot of bottlenose whale presence in early boreal summer. Habitat models were created by fitting generalised additive models of selected environmental variables to sighting occurrence and additional whale sightings given a first encounter (total number of sightings - 1) recorded in June 2014-2016. Higher occurrence was estimated at steeper topography and April-average chlorophyll concentration below 0.4 mg m^-3. Additional whale sightings given a first encounter were predicted to be higher at water depths (<1000 m) with steep topography, and deeper water (depths between 1300 and 2000 m) with a gentle seafloor slope. Spatial predictions largely corresponded with field observations that indicated high usage around the submarine canyon regions in the east and southeast of Jan Mayen Island. This study highlights the likely importance of steep and deep bathymetric features in shaping patterns of habitat use of this deep-diving species. Predictions of habitat use over a wider area not covered by the analysed surveys require validation; however, these data could inform conservation and management efforts to minimise spatial overlap between potential high-use areas and potentially disruptive anthropogenic activities.

KEY WORDS: Habitat use · Habitat models · Beaked whale · Multi-model inference · Generalised additive models · Bathymetry · Opportunistic sampling · North Atlantic