People and ecosystems

Understanding of the links between coral reef ecosystems, the goods and services they provide to people, and the wellbeing of human societies.


Ecosystem dynamics: past, present and future

Examining the multi-scale dynamics of reefs, from population dynamics to macroevolution


Responding to a changing world

Advancing the fundamental understanding of the key processes underpinning reef resilience.

Coral Bleaching

Coral Bleaching

Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au

Menu Image Menu Image Menu Image Menu Image Menu Image Menu Image Menu Image
Facebook Twitter YouTube FlickR

A new study suggests sharks will need to adapt, move or die as climate change could soon render their nurseries uninhabitable.

Baby sharks rely on coastal nursery-like spaces such as shallow lagoons and mangroves for food as well as protection from predators. But they also need to be robust enough to cope with the challenging conditions these environments throw at them—conditions that may soon become unbearable in a warming world.

“In shallow coastal habitats, baby sharks already have to tolerate the strain of high temperatures,” said the study’s lead author Dr Ian Bouyoucos, from the ARC Centre of Excellence for Coral Reef Studies at James Cook University (Coral CoE at JCU).

“The temperatures can also fluctuate dramatically on a daily basis. It’s the constant change that makes these environments ‘extreme’.”

Dr Bouyoucos said nursery areas are important for sustaining the local shark populations by serving as ‘safe havens’ for newborns and juveniles to learn critical survival and foraging skills. But the impacts of climate change are increasingly becoming a problem for their survival.

“We don’t know if sharks can adapt and can continue to use these important habitats early in life, or whether they will be able to find new nurseries, or whether populations will die off” he said.

Co-author Associate Professor Jodie Rummer, also from Coral CoE at JCU, says this is a case of adapt, move or die.

“Heatwaves due to climate change are becoming more frequent and severe, and lasting longer with climate change,” Dr Rummer said.

She said more work is needed to find current tolerance limits for newborn sharks to survive and thrive in shallow, warm nursery habitats.

“The temperature thresholds that limit their performance today can help us predict how future populations might fare as the waters continue to warm with climate change,” she said.

“But adaptation—changes in DNA over generations to accommodate new conditions—may not be possible. This is because sharks are slow to reach sexual maturity compared to most other fishes and do not reproduce as often or have as many babies. Therefore, not enough generations can go by fast enough to keep pace with the rate at which we—humans—are changing their habitats.”

Dr Rummer said there was a possibility newborn sharks could move to new nursery-like areas that are not as warm.

“Or, we might just see these shark populations disappear,” she said.

“This is a real risk. We know sharks are tolerating a lot already. The oceans, their habitats, are getting warmer, lower in oxygen, and lower in pH with climate change.”

As predators, sharks are essential for healthy ocean ecosystems. Without predators, whole ecosystems can collapse.

“We need to keep studying and protecting sharks,” Dr Bouyoucos said.

“Our sharks, ecosystems, and our futures all depend on us urgently cutting greenhouse gas emissions to curb climate change.”


Bouyoucos I, Simpfendorfer C, Planes S, Schwieterman G, Weideli O, Rummer J. 2022. ‘Thermally insensitive physiological performance allows neonatal sharks to use coastal habitats as nursery areas’. Marine Ecology Progress Series. DOI: 10.3354/meps13941


A selection of images can be used for media stories with credit to the photographer as stated in the file name. Please note these are for single use with this story only, not for any other story. No archival permissions are granted.


Ian Bouyoucos (Manitoba, CST)
E: ian.bouyoucos@umanitoba.ca

Jodie Rummer (Townsville, AEST)
P: +61 (0)439 166 171
E: jodie.rummer@jcu.edu.au

Researchers at the ARC Centre of Excellence for Coral Reef Studies at James Cook University have found that long hot summers can wreak havoc on the development of coral reef fish.

“The findings are a concern,” said study co-author, Professor Mark McCormick.In one of the longest studies of its kind, the researchers examined the impacts of water temperature, wind, rainfall and solar radiation on damselfish larvae around Lizard Island at the northern end of the Great Barrier Reef.

“We found that when ocean temperatures warmed beyond about 28°C, the pace of larval development slowed,” said study lead author, Dr Ian McLeod.

“To see adverse effects over the current-day temperature range raises concerns about the serious negative effects we may see when the ocean temperature warms with climate change.”

Most marine fishes go through a larval development stage in the open ocean when they are more vulnerable to predators.

Dr McLeod said the longer larvae remain in this stage the less likely they are to survive.

“Faster growth during the larval stage should lead to a survival advantage because they can develop sooner and get out of the dangerous pelagic environment faster,” he says.

However there is a ray of hope. The researchers also found a high level of variability in larval development in relation to temperature and other weather conditions.

“This high level of variability likely means that some fish will thrive in the changing conditions and pass on their genes to future generations” said Dr McLeod.

The authors hope that the results for this study will be used to help predict the effects of climate change on larval development of fishes.

Dr Ian McLeod is a former PhD Candidate at ARC CoE and is now a Senior Research Scientist at TropWATER, James Cook University.

Dr Ian McLeod
E: ian.mcleod1@jcu.edu.au
M: 0449 84 0 082
P: 07 4781 5474

Professor Mark McCormick
E: mark.mccormick@jcu.edu.au
M: 0409 371 015

Interannual variation in the larval development of a coral reef fish in response to temperature and associated environmental factors, by Ian M. McLeod, Rhondda E. Jones, Geoffrey P. Jones, Miwa Takahashi and Mark I. McCormick is published in the journal, Marine Biology. DOI 10.1007/s00227-015-2765-y

Please credit images as marked


Australian Research Council Pandora

Partner Research Institutions

Partner Partner Partner Partner
Coral Reef Studies

ARC Centre of Excellence for Coral Reef Studies
James Cook University Townsville
Queensland 4811 Australia

Phone: 61 7 4781 4000
Email: info@coralcoe.org.au