Researchers predict that as the oceans warm due to climate change, whale sharks, the world’s largest fish, could face an increased threat from collisions with large ships. The study published in Nature Climate Change suggests that the co-occurrence of whale sharks and shipping traffic could increase dramatically by the end of the century, putting this already endangered species at greater risk. The findings highlight the importance of considering climate change in efforts to protect vulnerable marine species.
Whale Sharks Facing Habitat Shifts Due to Climate Change
The study suggests the world’s biggest fish, the whale shark, will experience huge shifts in its distribution because of global warming. With the oceans warming, these adaptable marine animals are likely to move around a lot as their habitats change, and there could be more than 50% loss of core habitat in many areas by the end of the century under high emissions scenarios.
The recent ‘global reshuffling’ of whale shark populations could mean that they move to new hotspots for large ships, where the likelihood of lethal strikes on whale sharks would be much more frequent. To estimate future whale shark ranges, the researchers used current data from a satellite tracking study and global climate change models to predict patterns of his likely distribution under different climate scenarios, then compared these predictions with traffic levels. Ship density assesses possible coincidence rate of ship strikes.
Potential Impacts of Climate Change on Whale Shark Conservation
The study, which confirms the seasonal use of different habitats by whale sharks, has big implications when it comes to conserving them — since they are already listed as an endangered species. Writing in the journal Oryx, this group of researchers warns that unless major action is taken to limit carbon emissions, potentially turning large ships away from these clouds of food — which satellite data suggests are growing due to fishing operations as waters warm — could become nearly 15,000 times more common by the year 2101 compared with the present day.
But the researchers also say that this worst-case scenario could be alleviated if we are able to cool Earth down and slow overall warming and climate change. In a situation more aligned with the aims of the Paris Agreement — which seeks to limit global temperature rise to within 2 degrees Celsius (3.6 degrees Fahrenheit) above pre-industrial levels — some regions might experience core whale shark habitat gains, especially in Europe.
Implications for Endangered Species Management and Climate Action
Dr. Freya Womersley, who led the study, said it underlined the need to include climate change in the debate around vulnerable species management. ‘Our study illustrates the complex ways in which climate change has the potential to influence mobile top predators through interactions between humans and the environment,’ Ortega-Cisneros says.
Admitting that the study comes with a number of caveats, it shows how much climate change may be affecting even one of the largest fish species, which the researchers say underscores “the importance for policymakers and conservation organizations to consider the indirect effects of climate change in their efforts to protect vulnerable species such as whale sharks”. If we do something about climate change and reduce our greenhouse gas emissions, perhaps there’s a slightly brighter future for these ocean giants after all.
