Ship strikes now leading cause of whale deaths, study finds
Published in Science & Technology News
SEATTLE — With the near complete end of commercial whaling, ship collisions are now a leading cause of death worldwide for large whale species, according to new research published in Science.
Yet little is done to manage this risk, found authors of the study, led by the University of Washington.
In a first of its kind global analysis, scientists found that shipping overlaps with 92% of whale ranges, and less than 7% of the hot spots with the greatest collision risk had any management strategies in place to reduce strikes.
It wouldn’t take much, scientists found, to change that, because shipping is so concentrated in its intensity at global ports. Managing only 2.6% of the ocean’s surface to minimize risk to whales — by slowing ship speeds, or moving shipping lanes out of known migration and feeding areas for instance — would reduce risk at all of the known hot spots, the scientists found.
The new study quantified the risk for whale-ship collisions worldwide for four species: blue, fin, humpback and sperm whales.
Shippers and these whales share an increasingly busy ocean, with large vessels traveling the equivalent of more than 4,600 times the distance to the moon and back each year within their range, the scientists estimated.
Citizens of the world traversing multiple human boundaries, whales are victims of increasing human-caused stressors: noise, pollution, and now collisions with ships longer than a football field.
Ships and whales on a collision course
The world’s large whales are being killed by ship strikes, including humpbacks in the Pacific Northwest, and climate warming is expected to make the problem worse.
Climate change is predicted to accelerate the risk, noted Sue Moore, research scientist at the of the University of Washington’s Center for Ecosystem Sentinels, an author on the study and member of the U.S. Marine Mammal Commission. Melting arctic sea ice is predicted to bring ships into novel areas, putting whales, including bowhead and gray whales, at risk as they shift their range northward too, tracking preferred sea surface temperatures and food at the edge of the sea ice.
Whales play a critical role in marine ecosystems, including cycling nutrients particularly to the deep sea when they die. They have immense cultural importance to many peoples, the authors noted, and here in the Northwest, their societies, songs and language have been interwoven with human communities for as long as people and whales have shared the oceans. Yet whales remain highly vulnerable.
Here at home, voluntary slowdown programs have been implemented for commercial ships, such as the ECHO Program led by the Port of Vancouver with multiple partners and the Quiet Sound program, a project of the nonprofit Washington Maritime Blue in Washington waters. They are intended to reduce underwater noise when endangered southern resident killer whales are present. Underwater noise has been identified as one of the main threats to southern resident orca survival.
Slowing down ships has other benefits beyond reducing underwater noise; it also reduces risk of lethal ship strikes, reduces pollution for marine life and shoreside communities, and reduces the emission of greenhouse gases.
The ECHO and Quiet Sound programs have been gaining in popularity, with increasing numbers of shippers participating.
Anna Nisi, a postdoctoral researcher at the University of Washington and lead author on the paper, said the protections needed now are just one more extension of the societal steps taken to protect whales that have been so effective. “I do think this issue can feel so heavy and depressing for people understandably,” Nisi said. “But if you look at the trajectory as to conservation since the 1970s many populations have recovered so much, and there is so much more we can do.”
So far there has been no move to make slowdowns in Washington waters mandatory, or to expand the program in times and areas to extend protection for other species, such as for whales transiting Washington’s outer coast.
Mike Moore, vice president of the Pacific Merchant Shipping Association, said without more and better data he’d be reluctant to see an expanded footprint of shipping slowdowns. “I’d like to see a strong nexus between action and consequences, are you slowing down for virtue signaling and looking good, or are you doing good?”
In California waters, shippers’ speeds are tracked under the Whale Safe program, with shippers assigned grades on the Whale Safe speed zone website according to their operations within designated recommended slower speed zones.
The voluntary program has helped raise compliance with slower speeds, noted Doug McCauley and Rachel Rhodes, co-authors on the paper.
Rob Williams, chief scientist at the Seattle-based nonprofit Oceans Initiative, who was not involved in the paper, praised its value and thoroughness. Beyond advancing science, the paper is food for thought too, about our consumption, he noted.
“Maybe pause and be mindful and think about whether we need our widget the same day or we can slow down a bit,” Williams said.
Said McCauley, one of the paper’s co-authors: “How many whales are connected to that thing on your shelf?”
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