DOI: 10.5061/dryad.wm37pvmt5
title: Habitat use of the northern bottlenose whale (Hyperoodon ampullatus) near Jan Mayen, North Atlantic

description: 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 (&lt;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.
description: Visual sighting data of bottlenose whales were
 collected in June in 2014, 2015, and 2016, with search effort
 concentrating along the submarine canyon from north to southeast of Jan
 Mayen Island. Visual surveys were conducted by 2 dedicated observers from
 the deck whenever weather conditions permitted. Both observers made visual
 scans from bow to stern, with one observer searching across the starboard
 and the other across the port of the boat, together covering 360° around
 the vessel. Binoculars were used to confirm whale species and location
 once an animal was spotted. 
 When a sighting was made, the time, whale location (latitude and
 longitude), estimated sighting distance, bearing, group size, animal
 heading, and level and duration of seeking (behavioural indication of
 attractive movement towards the research vessel, as suggested by Whitehead
 & Hooker 2012) were recorded. Vessel GPS location and speed were
 automatically logged every 5 s in 2014 and 2015, and every 1 s in
 2016. Following a sighting,
 the whales were often approached for tagging. If successful, the tagged
 whale would be tracked for the duration of the tag deployment. Sighting
 and effort data during tagging and tracking periods were excluded from the
 analyses. A total of 26 of 220 sightings
 were scored in the field as whales being attracted to the research vessel
 (labelled as ‘strong seekers’ as part of the field data collection) and
 were discarded prior to detection function modelling. The truncation
 distance was set to 700 m, retaining approximately 167 sightings, which
 was ~85% of non-seeking sightings.
description: R or MS Excel