“Less Than 7% of Whale Collision Hotspots Implement Safety Precautions”

Each year, thousands of whales suffer injuries or fatalities due to ship strikes, with large container vessels responsible for transporting 80% of global trade being the primary culprits. Ship collisions rank as the leading cause of death for large whale species. However, access to comprehensive data on these incidents remains limited, hindering conservation efforts for endangered whale populations. Led by the University of Washington, the research team has quantified the global risk of whale-ship collisions for the first time.

The study, published in Science on November 21, indicates that global shipping traffic occupies approximately 92% of the habitats of these whale species.

“This means ships travel vast distances—equivalent to thousands of trips to the moon and back—through areas inhabited by these species every year, and this issue is expected to worsen as global trade expands,” explained Briana Abrahms, a senior author and UW assistant professor of biology associated with the Center for Ecosystem Sentinels.

Anna Nisi, the lead author and a postdoctoral researcher at UW, stated, “Previous studies on whale-ship collisions have generally been confined to local or regional scopes, such as along the U.S. east and west coasts, leaving many risks unassessed. Our study seeks to bridge those gaps and gain insight into collision risks at a global scale. It’s crucial to identify areas where collisions are likely to occur, as there are straightforward interventions that could significantly lower these risks.”

Only around 7% of the regions identified as high-risk for whale-ship collisions currently have any protective measures in place, which primarily consist of speed reductions—both compulsory and voluntary—for ships navigating through critical whale habitats.

Abrahms acknowledged, “While our findings raise significant concerns, there are also promising aspects. For instance, a mere additional 2.6% of the ocean’s surface would need management measures to safeguard all the high-risk collision hotspots we’ve pinpointed.”

Heather Welch, a co-author and research scientist with NOAA and UC Santa Cruz, noted, “It’s not often that we find such an optimal balance between industrial and conservation goals. Usually, extensive limits on industrial activities are necessary to fulfill conservation objectives. Here, there is a substantial conservation advantage for whales that imposes minimal costs on the shipping industry.”

The study identified several high-risk zones for the four assessed whale species, mainly located near coastal regions in the Mediterranean, certain areas of the Americas, southern Africa, and parts of Asia.

The international research team, comprising scientists from five continents, analyzed the habitats of these whale species by consolidating data from various sources, such as government surveys, public sightings, tagging studies, and whaling records. They amassed approximately 435,000 unique whale sightings, which they combined with navigation data from 176,000 cargo vessels from 2017 to 2022, tracked by the ships’ automatic identification systems and processed using an algorithm developed by Global Fishing Watch to determine high-traffic zones for encounters between whales and ships.

In their findings, the researchers highlighted regions already recognized as high-risk for ship strikes, including the Pacific coast of North America, Panama, the Arabian Sea, Sri Lanka, the Canary Islands, and the Mediterranean. They also revealed lesser-studied regions at high risk for whale-ship collisions, such as southern Africa, the coasts of Brazil, Chile, Peru, Ecuador in South America, the Azores, and East Asia off the coasts of China, Japan, and South Korea.

The study observed that mandatory measures to mitigate collisions were extremely scarce, affecting only 0.54% of blue whale hotspots and 0.27% of humpback hotspots, with none overlapping fin or sperm whale hotspots. Although many collision hotspots are situated within marine protected areas, these zones often lack vessel speed regulations because they were mainly created to address fishing and industrial pollution.

For all four whale species studied, over 95% of collision hotspots were located close to shore within exclusive economic zones of nations, allowing countries to enact their own protective regulations in collaboration with the U.N.’s International Maritime Organization.

Nisi expressed encouragement regarding the fact that most high-risk regions are found within exclusive economic zones, stating, “This indicates that individual countries possess the capacity to shield the most vulnerable areas.”

The limited measures currently applied are concentrated along North America’s Pacific coast and the Mediterranean. Besides speed reductions, alternatives to decrease whale-ship strikes involve adjusting vessel routes away from locations inhabited by whales or establishing alert systems to inform authorities and sailors when whales are nearby.

“Reducing vessel speeds in these hotspots yields additional advantages, such as minimizing underwater noise pollution, lowering greenhouse gas emissions, and decreasing air pollution, all of which benefit coastal residents,” Nisi added.

The researchers hope that their global analysis will inspire localized or regional studies to map collision hotspots in greater detail, support advocacy initiatives, and consider climate change’s effects, which are likely to alter both whale and ship distributions as sea ice disappears and ecosystems change.

“Preventing whale-ship strikes presents a significant global hurdle. We have observed benefits from decreasing ship speeds on smaller scales, as seen in programs like ‘Blue Whales Blue Skies’ in California. Expanding such initiatives will necessitate a collaborative effort from conservation organizations, governmental bodies, and shipping companies,” asserted Jono Wilson, director of ocean science at the California Chapter of The Nature Conservancy, which recognized the necessity for this research and facilitated its funding. “Whales are essential to marine ecosystems, and this study provides measurable insights into high-risk collision zones and the areas that require focus for maximum impact.”

Co-authors of the study include Stephanie Brodie from Australia’s Commonwealth Scientific and Industrial Research Organisation; research scientists Callie Leiphardt, Rachel Rhodes, and professor Douglas McCauley, all from the University of California, Santa Barbara; Elliott Hazen from NOAA’s Southwest Fisheries Science Center; Jessica Redfern from the Anderson Cabot Center for Ocean Life at the New England Aquarium; Trevor Branch, a professor at UW; Sue Moore of the Center for Ecosystem Sentinels; André Barreto from Brazil’s Universidade do Vale do Itajaí; John Calambokidis, senior research biologist with Cascadia Research Collective; Tyler Clavelle, chief scientist David Kroodsma, and senior manager Tim White from Global Fishing Watch; research scientists Lauren Dares, Chloe Robinson from Ocean Wise; Asha de Vos from Oceanswell in Sri Lanka and the University of Western Australia; Shane Gero from Carleton University; biologist Jennifer Jackson from the British Antarctic Survey; Robert Kenney, emeritus research scientist from the University of Rhode Island; Russell Leaper from the International Fund for Animal Welfare; Ekaterina Ovsyanikova from the University of Queensland; and Simone Panigada from Italy’s Tethys Research Institute.

The research received financial support from organizations such as The Nature Conservancy, NOAA, the Benioff Ocean Science Laboratory, the National Marine Fisheries Service, Oceankind, Bloomberg Philanthropy, Heritage Expeditions, Ocean Park Hong Kong, National Geographic, NEID Global, and the Schmidt Foundation.