Water temperature as a driver of long-distance whale shark migration

25-November-2021 (written by Lucy Arrowsmith)

The SequeiraLab is happy to announce that the research paper 'Water temperature is a key driver of horizontal and vertical movements of an ocean giant, the whale shark (Rhincondon typus)' led by Lucy Arrowsmith and co-authored by Ana Sequeira, Charitha Pattiaratchi and Mark Meekan, has just been published in the journal Marine Ecology Progress Series! This paper, investigates the relationship between a whale shark's horizontal and vertical movements with oceanographic features, including temperature, to investigate thermoregulation.

We found that during the whale shark long-distance movement of 5,380 km from Christmas Island, Australia, to the Banda Sea, Indonesia, water temperature was the most important driver of migration and explained interesting patterns associated with this animal's diving behaviour. Across the track the shark occupied a relatively narrow temperature range of 24 - 29 ℃, following frontal systems and water masses within these temperatures possibly to also take advantage of foraging opportunities. We also found evidence supporting the hypothesis of behavioural thermoregulation, by which the animal spends time at the surface to warm up and balance heat lost during deep dives into cooler waters. Our results show that the duration of pre- and post-dive surface intervals varied according to the type of dive performed by the shark (i.e., searching or foraging), and were longer when the animal went to deeper waters.

This collaborative research project worked closely with the Australia Institute of Marine Science, the School of Biological Sciences and the Oceans Graduate School at The University of Western Australia. Congratulations to Lucy for this great achievement !