The global population of the world’s largest fish - the whale shark - is decreasing and new research says this is because they’re getting hit by ships. 

Scientists tracked 348 whale sharks that had been satellite tagged - an electronic tag which helps researchers see when, where and how marine animals travel. 

The satellite tags recorded cases of whale sharks moving into shipping lanes - routes and waterways which large ships use - and sinking slowly to the sea floor. 

A statement from the University of Auckland said this was the ‘smoking gun’ of a “lethal ship strike”.

The researchers said the results point to potentially high levels of undetected or unreported ship strikes, which could explain why whale shark populations are declining despite protection.  

“Collision mitigations in high-collision-risk areas appear necessary to help conserve this iconic species,” the researchers said.

The research, released on Tuesday morning, also found that slowing ships would cut the threat of lethal collisions, reduce sound pollution that harms underwater creatures, and lessen greenhouse gas emissions.

Whale sharks in New Zealand did not take part in the study because none of them had satellite tags. 

However, the University of Auckland’s Dr Mark Erdmann, who co-authored the study which was led out of the United Kingdom, said “collision risk with marine vessel traffic is only starting to be recognised as a serious threat that may require mitigation efforts, and it’s important that New Zealand take this seriously”. 

“We really know almost nothing about where New Zealand’s whale sharks move or spend most of their time,” Erdmann said. 

There were plans in the future to start a whale tagging programme in Aotearoa to “better understand” their movements in our coastal waters, Erdmann said. 

Top Image: A whale shark is the world’s largest fish. (File photo) Photo: iStock

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