University of Southampton

05/10/2022 | Press release | Distributed by Public on 05/10/2022 02:59

Shipping poses significant threat to the endangered whale shark

The team mapped shark 'hotspots' which overlapped with global fleets of cargo, tanker, passenger, and fishing vessels - the types of large ships capable of striking and killing a whale shark - to reveal that over 90 per cent of whale shark movements fell under the footprint of shipping activity.

The study also showed that whale shark tag transmissions were ending more often in busy shipping lanes than expected, even when they ruled out technical failures. The team concluded that loss of transmissions was likely due to whale sharks being struck, killed and sinking to the ocean floor.

University of Southampton PhD Researcher Freya Womersley, who led the study as part of the Global Shark Movement Project said: "The maritime shipping industry that allows us to source a variety of everyday products from all over the world, may be causing the decline of whale sharks, which are a hugely important species in our oceans."

Whale sharks are slow-moving ocean giants which can grow up to 20m in length and feed on microscopic animals called zooplankton. Whale sharks help regulate the ocean's plankton levels and play an important role in the marine food web and healthy ocean ecosystems.

Professor David Sims, Senior Research Fellow at the MBA and University of Southampton and founder of the Global Shark Movement Project said: "Incredibly, some of the tags recording depth as well as location showed whale sharks moving into shipping lanes and then sinking slowly to the seafloor hundreds of metres below, which is the 'smoking gun' of a lethal ship strike."

"It is sad to think that many deaths of these incredible animals have occurred globally due to ships without us even knowing to take preventative measures." says Sims.

At present there are no international regulations to protect whale sharks against ship collisions. The research team say that this species faces an uncertain future if action is not taken soon. They hope their findings can inform management decisions and protect whale sharks from further population declines in the future.

Freya said: "Collectively we need to put time and energy into developing strategies to protect this endangered species from commercial shipping now, before it is too late, so that the largest fish on Earth can withstand threats that are predicted to intensify in future, such as changing ocean climates."

Watch our interview with Freya below.