Research reveals thousands of whales at risk of deadly ship collisions

By Stephen Beech

Less than one in 10 global hotspots for potentially fatal whale collisions with ships have protection measures in place, warns a new study.

Thousands of ocean giants are injured or killed each year after being struck by shipping, particularly large container vessels that ferry 80% of the world’s traded goods.

Collisions are the leading cause of death worldwide for large whale species.

But less than seven percent of collision hotspots have protection measures in place, say scientists.

Global data on ship strikes involving whales are hard to come by, impeding attempts to protect vulnerable whale species.

But a new study has for the first time quantified the risk of whale-ship collisions worldwide for four geographically widespread species - blue, fin, humpback and sperm whales - that are threatened by shipping.

The findings of the international research team, published in the journal Science, show that global shipping traffic overlaps with about 92% of the whale species’ ranges.

The highest-risk areas for the four while species included in the study lie mostly along coastal areas in the Mediterranean, portions of the Americas, southern Africa and parts of Asia.

Study senior author Dr. Briana Abrahms, of the University of Washington, said: “This translates to ships traveling thousands of times the distance to the moon and back within these species’ ranges each and every year, and this problem is only projected to increase as global trade grows in the coming decades.”

Lead author Dr. Anna Nisi, a University of Washington postdoctoral researcher in the Center for Ecosystem Sentinels, said: “Whale-ship collisions have typically only been studied at a local or regional level - like off the east and west coasts of the continental U.S., and patterns of risk remain unknown for large areas.

“Our study is an attempt to fill those knowledge gaps and understand the risk of ship strikes on a global level.

"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.”

The team found that less than one in 12 areas at the highest risk of collisions have any measures in place to protect whales from the threat.

The measures include speed reductions, both mandatory and voluntary, for ships crossing waters that overlap with whale migration or feeding areas.

Dr. Abrahms said: “As much as we found cause for concern, we also found some big silver lining.

"For example, 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.”

Co-author Heather Welch, a research scientist with the National Oceanic and Atmospheric Administration and the University of California, said: “Trade-offs between industrial and conservation outcomes are not usually this optimal.

“Oftentimes industrial activities must be greatly limited to achieve conservation goals, or vice versa.

"In this case, there is a potentially large conservation benefit to whales for not much cost to the shipping industry.”

They collected more than 435,000 unique whale sightings.

They then combined the database with information on the courses of 176,000 cargo vessels from 2017 to 2022 - tracked by each ship’s automatic identification system and processed using an algorithm from Global Fishing Watch - to identify where whales and ships are most likely to meet.

The study uncovered regions already known to be high-risk areas for ship strikes: North America’s Pacific coast, Panama, the Arabian Sea, Sri Lanka, the Canary Islands and the Mediterranean Sea.

But it also identified understudied regions at high risk for whale-ship collisions, including southern Africa; South America along the coasts of Brazil, Chile, Peru and Ecuador; the Azores; and East Asia off the coasts of China, Japan and South Korea.

The team found that mandatory measures to reduce whale-ship collisions were very rare, overlapping just 0.54% of blue whale hotspots and 0.27% of humpback hotspots, and not overlapping any fin or sperm whale hotspots.

Though many collision hotspots fell within marine protected areas, those preserves often lack speed limits for vessels, as they were largely established to curb fishing and industrial pollution.

For all four species, the vast majority of hotspots for whale-ship strikes - more than 95% - hugged coastlines, falling within a nation’s exclusive economic zone.

That means that each country could implement its own protection measures in coordination with the U.N.’s International Maritime Organisation.

Dr. Nisi said: “From the standpoint of conservation, the fact that most high-risk areas lie within exclusive economic zones is actually encouraging.

“It means individual countries have the ability to protect the riskiest areas.”

She added: “Lowering vessel speed in hotspots also carries additional benefits, such as reducing underwater noise pollution, reducing greenhouse gas emissions, and cutting air pollution, which helps people living in coastal areas."

The team hope the study, published in the journal Science, will spur local or regional research to map out the hotspot zones in finer detail.

Co-author Professor Jono Wilson, director of ocean science at the California Chapter of The Nature Conservancy, said: “Protecting whales from the impact of ship strikes is a huge global challenge.

"We’ve seen the benefits of slowing ships down at local scales through programs like ‘Blue Whales Blue Skies’ in California.

"Scaling up such programs will require a concerted effort by conservation organizations, governments and shipping companies.”

He added: “Whales play a critical role in marine ecosystems.

"Through this study, we have measurable insights into ship-collision hotspots and risk and where we need to focus to make the most impact.”