The importance of spinner dolphin (Stenella longirostris) resting habitat: implications for management

Linking key ecological characteristics with animal behaviour is essential for identifying and protecting important habitats that support life functions. Spinner dolphins display a predictable diurnal behavioural pattern where they forage offshore at night and return to sheltered bays during daytime to rest. These bays, which are also subject to considerable use by humans, have long been recognized as key habitats for this species although the extent to which dolphins rely on specific characteristics of these habitats for rest has not been quantified. An integration of boat-based and land-based group focal follow sampling regimes and three gradient boosting generalized additive models were developed to identify habitat features that contribute to the occurrence of resting spinner dolphins in coastal waters off Hawai'i Island. Two ‘in-bay’ models used data collected within bays, and a third ‘coastal’ model (near-shore, outside of bays) used data collected both inside and outside of bays....