Satellite tracking of endangered or threatened animals can facilitate
informed conservation by revealing priority areas for their protection. Basking sharks
(Cetorhinus maximus, n=11) were tagged during the summers of 2013, 2015, 2016
and 2017 in the Isle of Man (IoM; median tracking duration 378 days (range: 89-804
days); median ...
Satellite tracking of endangered or threatened animals can facilitate
informed conservation by revealing priority areas for their protection. Basking sharks
(Cetorhinus maximus, n=11) were tagged during the summers of 2013, 2015, 2016
and 2017 in the Isle of Man (IoM; median tracking duration 378 days (range: 89-804
days); median minimum straight-line distance travelled 541 km (range: 170-10,406
km). Tracking revealed three movement patterns: (i) coastal movements within IoM
and Irish waters, (ii) summer northward movements to Scotland and Norway and (iii)
international movements to Morocco and Norway. One tagged shark was bycaught
and released alive in the Celtic Sea. Basking sharks displayed inter-annual site
fidelity to the Irish Sea (n=3), a Marine Nature Reserve (MNR) in IoM waters (n=1),
and Moroccan waters (n=1). Core distribution areas (50% kernel density estimation)
of five satellite tracked sharks in IoM waters were compared with 3,902 public
sightings between 2005 and 2017, highlighting West and South coast hotspots.
Location data gathered from satellite tagging broadly corresponds to the current
boundaries of MNRs in Manx waters. However, minor modifications of some MNR
boundaries would incorporate ~20% more satellite tracking location data from this
study, and protective measures for basking sharks in IoM waters could further aid
conservation of the species at a local, regional and international scale. We also show
the first documented movement of a basking shark from the British Isles to Norway,
and the longest ever track for a tagged basking shark (two years and two months,
804 days).
