SEATTLE — Today, the leading cause of death in whales is due to collisions with large vessels. A study led by researchers at the University of Washington found that introducing regulations in very select places could have a major impact on whale mortality.
Global data on whale and ship collisions is hard to come by, so a team led by University of Washington researchers set to work on quantifying the risk for whale-ship collisions for four species of whale: blue, fin, humpback and sperm whales.
The team found that 92% of whale habitat overlaps with global shipping routes, meaning there are very few places where the creatures can go that they are safe from vessels. This number is likely to increase as global shipping grows, said the study, which was published Nov. 21 in the journal Science.
While previous studies looked at more limited areas for risk of whale-ship collisions, this one examined the issue on a global scale to help fill in knowledge gaps.
"It’s important to understand where these collisions are likely to occur because there are some really simple interventions that can substantially reduce collision risk," said lead author Anna Nisi, a UW postdoctoral researcher in the Center for Ecosystem Sentinels.
The research team found that only 7% of areas where whale-ship collisions are most likely to happen have any regulations in place to protect whales. However, they also found that taking action in a minimal number of places would go make a big difference.
"Implementing management measures across only an additional 2.6% of the ocean’s surface would protect all of the highest-risk collision hotspots we identified,” said senior author Briana Abrahms, a UW assistant professor of biology and researcher with the Center for Ecosystem Sentinels.
These highest-risk areas are largely along coastal areas in the Mediterranean, portions of the Americas, southern Africa and parts of Asia.
For all four whale species that were studied, the majority of collision hotspots were along coastlines within a nation's exclusive economic zone. This means countries have the jurisdiction to take action and implement protection measures, the study found.
In addition to speed reduction regulations, changing vessel routes and implementing warning systems that alert mariners when whales are near by could be effective strategies to reduce collisions.