Variable response of coastal sharks to severe tropical storms: environmental cues and changes in space use

Acute disturbance events like tropical storms can have significant effects on coastal habitats and animals that utilise them. We examined environmental parameters as cues for flight behaviour based on movement data from 5 species of elasmobranch (Carcharhinus limbatus, C. tilstoni, C. melanopterus, C. sorrah and C. amboinensis) during 3 tropical storm events in 2 coastal bays on 2 continents (Cleveland Bay, Australia, and Terra Ceia Bay, USA). Individuals were monitored using passive acoustic telemetry before, during and after the storms. Short-term effects on movement and distribution were investigated in relation to environmental parameters (barometric pressure, wind speed and wave height) along with longer-term changes in size and location of activity spaces of individuals due to extreme weather events. Short-term flight behaviour was observed in 4 species, with C. melanopterus the only species showing no reaction to storm events. Change of activity space size and location varied within the 2 study sites, with significant changes in activity spaces only occurring in Terra Ceia Bay. Examination of environmental parameters as cues for flight behaviour showed that species had varying tolerances to environmental conditions during storm events. Flight behaviour was observed in juvenile individuals that had not experienced such conditions before, which may suggest that this behavioural response is innate