Knowledge regarding the movement ecology of the endangered Isurus oxyrinchus (shortfin mako sharks) remains unknown or greatly limited. The aim of this thesis is to help bridge that gap by investigating the horizontal and vertical movements of satellite tracked and endangered in the North Atlantic, to then identify behavioural patterns and determine potential environmental drivers (sea surface temperature and mass chlorophyll a concentration). Results indicate that 97% of the observations reflect normal Diel Vertical Migration (nDVM), whereby the sharks descend around dawn, spending more time in deeper waters during the day before ascending around dusk and spending most of the night close to the surface. Within nDVM, two distinct behaviours were identified and termed: surface-oriented behaviour and depth-oriented behaviour. Sea surface temperature (SST) had a statistically significant effect on the choice of behaviour, with surface-oriented behaviour more prevalent under a breakpoint of 24°C, an equal probability at exactly 24°C and a shift to a higher probability of depth-oriented behaviour when SSTs greater than 24°C. Knowing how sharks respond to changes to the physical environment is crucial for the management of the species and to predict how their ecology will be affected by climate change.
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