Sharks walk away from climate change

Professor Jodie Rummer from James Cook University’s College of Science and Engineering and ARC Centre of Excellence for Coral Reef Studies co-authored a study on the epaulette shark that—using its paired fins— can walk, both in and out of water.

She said few studies have investigated the mechanics of the sharks’ walking and swimming, and not in newly hatched neonates, as in this study.

“The epaulette shark easily transitions from submerged walking in an aquatic environment to walking on land. This means that, in the wild, when it experiences temperature fluctuations and oxygen limitations, among other environmental challenges, it may just move to more favourable conditions,” said Dr Rummer.

She said this makes the epaulette shark ideal for studying the range of physiological, morphological, and biomechanical adaptations experienced by species that occupy the shallow coral reef flats. These traits may be necessary for them to survive future ocean conditions, which is why she and her team have been studying this little walking shark since 2012.

“Studying epaulette shark locomotion allows us to understand this, and perhaps related-species’ abilities to move within their habitats, for example, by crawling into the tiny crevices of the coral reef matrix to hide, as well as moving away from challenging conditions that they might experience,” said Dr Rummer.

She said the study showed the mechanics of neonate and juvenile epaulette shark movement remained the same even as their body shape and feeding strategy changed.

“Elevated temperatures, in particular, result in early hatching, smaller sizes, increased metabolic costs, altered colouration, and mortality over the span of months. The ability of the epaulette shark to move efficiently among microhabitats under these challenging environmental conditions may give them a distinct advantage,” said Dr Rummer.

“We feel that the epaulette shark is an important bio-indicator species here on the Great Barrier Reef and a flagship for conservation and climate change education.”

Paper available here.

Images available here.