Climate action essential to protect global fish stocks, Monash sustainability expert warns
Professor Craig White and Professor Dustin Marshall
As climate change accelerates, the world’s fisheries face steep declines in productivity, a threat that demands urgent, forward-looking policy action, according to Monash University Faculty of Science Associate Dean for Sustainability and Society, Professor Annette Bos.
“As the climate changes, marine species will shift and adapt in ways that directly affect global food supplies,” said Professor Bos, who also heads the Sustainable Development Education team at the Faculty.
“Keeping global warming to 1.5 degrees is not just a target; it is crucial for sustaining fishing yields and supporting the communities most at risk when ecosystems decline,” she said.
“Achieving this will require strong, future-focused policies that protect our oceans and the people who depend on them.”
Her comments come as new modelling from Monash University scientists reveals how climate change will alter fishing yields in many regions, threatening food security, livelihoods and the future of marine life as a sustainable food source.
Existing prediction models have looked at how fish species respond to warming temperatures in the absence of evolutionary change. However, research published today in Science now looks at how fish will evolve in response to future climates.
Fisheries provide billions of people with animal protein, for which the demand is predicted to increase. But as oceans warm and weather patterns shift, fish are evolving, breeding less or disappearing from waters entirely.
Researchers found that evolutionary responses to global change are likely to reduce the sustainability of fisheries and have negative consequences for global fisheries yields.
Study lead author Professor Craig White, Head of the School of Biological Sciences at the Faculty of Science said he predicts that global warming will cause fish to grow faster but to mature earlier, decreasing their maximum size.
“This evolution is good for fish but bad for fisheries. Evolution negates the impacts of global warming on fish fitness but exacerbates the impact on sustainable harvests,” said Professor White.
“Every degree of warming is predicted to decrease fisheries production; however, a good climate policy that limits global warming to ~1.5 °C has the potential to preserve millions of tonnes of fisheries production that would otherwise be lost.”
The study, undertaken in collaboration with Professor Jan Kozłowski from Jagiellonian University in Poland, implemented a new life-history model that was tested using data on nearly 3,000 fish species and predicted how life-history evolution will alter sustainable harvests in 43 of the world’s largest fisheries.
Professor Dustin Marshall, Head of the Marine Evolutionary Ecology Research Group at Monash University, said that consideration of evolution is critical for predicting how climate change will impact the ecosystem services that humans rely on.
“Most projections assume that evolution will mitigate the impacts of climate change. While that is true for the persistence of species, the opposite can be the case for ecosystem services,” said Professor Marshall.
Professor Damian Dowling, Director of Climate Change Science Hub at Monash University, said the findings have important implications for future fisheries management and demonstrate the value of sustained investment in fundamental science for shaping effective climate and sustainability policy.
“Years of research by this team into how organisms respond to environmental change have enabled them to apply that knowledge to the future sustainability of fisheries,” Professor Dowling said.
“The study shows that evolutionary responses of global fish populations to climate warming will not safeguard harvests — and may instead amplify the risks to sustainable yields. Strong, coordinated climate action is therefore essential to maintain resilient marine ecosystems and secure sustainable harvests for generations to come.”
Key findings of the research:
- Over time, fish will evolve to better handle warmer water, which helps them survive and reproduce despite the changing climate.
- While the fish themselves might cope better, this evolutionary process actually makes it worse for human fishing, leading to smaller catches.
- This evolutionary change will cause the economic or volume losses to the fishing industry to be 50 per cent higher than they would be if the fish did not adapt at all.
- The study emphasises the need for a strong climate policy that will limit global warming to 1.5 °C. This will preserve millions of tonnes of fishery production that would otherwise be lost, with every degree of warming further reducing fisheries production.
Read the research paper: https://doi.org/10.1126/science.aea1341
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