Cargo Ships Are Killing Whale Sharks
New research shows these gentle giants are often on a collision course with large ocean vessels
Sarah Kuta
Daily Correspondent
May 17, 2022
Whale sharks are the largest fish on Earth. Pexels
Whale sharks, the largest fish on Earth, have been mysteriously vanishing from the ocean without a trace over the last 75 years—and marine scientists couldn’t figure out why. When they die, the bodies of these massive, endangered sharks, which are typically 18 to 32 feet long and weigh about 15 tons, sink to the seafloor, so researchers can’t easily do a post-mortem.
Now, new research suggests that cargo ships and other large vessels are likely responsible for killing these gentle giants, contributing to a worldwide population decline of around 50 percent in the last 75 years. A new study in the journal Proceedings of the National Academy of Sciences finds that colliding with large ships “may be a greater cause of death for the world’s largest fish … than anyone previously realized,” Freya Womersley and David Sims, marine ecologists at the University of Southampton and study co-authors, write for the Conversation.
To probe the sharks’ unexplained disappearances, the researchers compared the satellite-tracked movements of 348 whale sharks with maps of global shipping routes in the Atlantic, Indian and Pacific oceans from 2005 to 2019. They found a lot of similarities: 92 percent of sharks’ horizontal space and nearly 50 percent of their vertical space overlapped with large vessel traffic, putting them on a potential collision course with ships that are larger than 300 gross tons.
Sharks were most at risk while spending time near the water’s surface (where they regularly feast on zooplankton), the researchers found. The most dangerous places for whale sharks to swim, according to the data, are the Gulf of Mexico, the Arabian Gulf and the Red Sea, where some of the world’s busiest ports are located.
More:
https://www.smithsonianmag.com/smart-news/cargo-ships-are-killing-whale-sharks-180980101/