A Win-Win for Whales and Air Quality

Novel program on the US West Coast incentivizes cargo ships to slow down to protect marine mammals, reduce emissions.

Bus-sized whales evolved without concern for the 1,000-foot-long cargo ships that have filled their oceanic highways in the last century. Unfortunately, that means that on the US West Coast, home to nine endangered whale species, collisions with shipping vessels have become the leading cause of whale deaths, with an estimated 80 deaths a year. The shipping industry is also under fire for its high fossil fuel emissions — if shipping were a country, it would be the sixth biggest emitter of greenhouse gases globally. Conveniently, however, these two seemingly unrelated challenges have a common solution: reducing shipping speeds.

blue whale

​The West Coast has long struggled to address shipping-related whale deaths. In part that’s because humpback, gray, fin, and blue whales typically sink upon death, making it harder to track the impact of ship strikes. Photo of blue whale courtesy of NOAA.

The Protecting Blue Whales and Blue Skies program, a partnership between air pollution regulators and marine researchers, is honing in on this common ground to provide monetary rewards to cargo ships that reduce their speeds in seasonally designated slow zones along the California coast where endangered whales are most at risk. As eco-friendly shipping has become more of a public priority recently, the program has seen a leap in compliance with its voluntary slow-down requests.

The West Coast has long struggled to address shipping-related whale deaths. Part of the difficulty is that whales and ships are limited in the ways they can avoid each other. Shipping companies say steering such large vessels to avoid whales would be an almost impossible, dangerous maneuver. And whales, with limited evolutionary defensive behaviors, are often unaware of the threat until it is too late. A design feature of cargo ships, known as the bow null effect, blocks the sound of the ship at the front of the boat. Whales and other marine mammals, distressed by the loud sounds of ship engines, are drawn to this quiet zone directly in the path of the approaching vessel, making them particularly vulnerable.

Research supports the idea that reducing ship speed can help reduce the fatality of whale-ship collisions. In 2013, the Ecological Society of America published a paper finding that speed reductions were “a powerful tool” for reducing whale deaths. Focused on the US East Coast, where regulators implemented mandatory speed reduction zones to protect the critically endangered North Atlantic right whale beginning in 2008, the study calculated a 90 percent reduction in the risk of whale deaths if ships slowed their speed to 10 knots or less, which is about 7 miles per hour slower than average speeds.

Unfortunately, mandatory regulations have been harder to implement along the California coast. North Atlantic Right whales have a unique tendency to float upon death, making it easier to track the impact of ship strikes on mortality. That trait is not shared by their West Coast counterparts: humpback, gray, fin, and blue whales typically sink before they are found in the ocean or wash ashore, leaving no or limited evidence of ship strikes.

“It’s a really hard issue to quantify because the ocean is so dynamic,” said Callie Steffen, a project scientist at Benioff Ocean Science Laboratory, noting that as few as one in ten whales killed by ship strikes are recorded.

Without sufficient data to support mandatory regulations, West Coast regulators and scientists have instead established voluntary speed reduction zones in designated marine sanctuaries to protect whales during seasonal migrations along the California coast. In these zones, NOAA requests that shipping companies slow down to a safer 10 knots or less. Modeling by researchers suggests that if 80 percent of shipping companies complied with slower speed requests in Southern California, whale deaths could be lowered by 30 percent.

But voluntary speed reduction zones are just that: voluntary. In the Panama Canal and Strait of Gibraltar, similar requests to shipping companies returned low compliance levels, with less than 10 percent of ships slowing down. And rates haven’t been much better in the US. In 2007, when four blue whale deaths from ship strikes were recorded in the Santa Barbara Channel in the span of three months, the National Oceanic and Atmospheric Administration began issuing voluntary slow-down requests to shipping companies in the area. But by 2010, the number of ships adhering to slower speeds had only reached 12 percent.

cargo ship

The Protecting Blue Whales and Blue Skies program pays shipping companies to reduce cargo ship speeds in designated zones. It also ranks participating companies annually based on what percentage of their ships complied with slower speed requests. Photo by Ron Beton.

As marine researchers wondered how to convince more ships to slow down to protect whales, regulators were also testing slowdown requests in Los Angeles, but for an entirely different reason. In 2006, after finding the shipping industry to be responsible for almost half of the city’s harmful air pollution, the Ports of Long Beach and Los Angeles Air Pollution Control District began requesting ships slow down in return for financial incentives. The resulting Vessel Speed Reduction Program rewards ships that approach or depart the port at 12 knots or less by returning 15 percent of all port costs back to compliant shipping companies. By 2019, the number of ships complying with the program had climbed to 90 percent — even higher than compliance levels with the mandatory speed limits established on the US East Coast.

As results of these voluntary emissions-motivated slowdowns emerged, marine researchers began to collaborate with air pollution regulators on their shared goals. In 2014, a coalition between the Santa Barbara Air Pollution Control District, NOAA marine sanctuaries, the nonprofit Center for Biological Diversity, and six major shipping companies began a voluntary slow-down trial program. The program incentivized shipping companies to participate with a $2,500 payment, intended to offset any related business costs, for each ship that passed through the Santa Barbara Channel and adhered to slower speed requests.

After a successful first year, the trial became the long-term Protecting Blue Whales and Blue Skies program, which ranks participating companies annually based on what percentage of their ships complied with slower speed requests, and provides positive press for companies that do so. Experts say that between 2017 and 2022, the number of complying ships in sanctuary zones grew to 60 percent. Today, over 500 ships from different shipping companies participate in the program, reducing tens of thousands of greenhouse gas emissions.

“It’s becoming more and more compelling for the companies every year,” said Jessica Morten, a NOAA affiliate and resource protection specialist at Greater Farallones National Marine Sanctuary who works in shipping company outreach at the Protecting Blue Whales Blue Skies program. Morten thinks that companies, which are increasingly under consumer scrutiny for sustainability, are motivated by “positive press that adds value to their brands.” According to the program website, participating companies now account for 90 percent of all ships that travel through West Coast voluntary speed reduction zones.

Despite the challenges, companies are jumping on board. Many that are eligible to receive payments to offset the costs of slower shipping speeds are even returning their checks in support of the program. Lee B. Kindberg, the head of environment and sustainability at Maersk, one of the shipping companies that returned these incentives, says that the monetary rewards are “less motivating than the recognition.” She says that the press releases by Protecting Blue Whales and Blue Skies “often get the attention of customers,” who are particularly interested in emissions reductions.

Along with rerouting shipping lanes, the Center for Biological Diversity is pushing for mandatory shipping speed regulations on the West Coast to match those in place on the East Coast.

But whales are difficult to predict, and establishing effective slow down zones is complicated. “It’s important to be really clear where the caveats are,” said Dr. Elliott L. Hazen, a NOAA research scientist who works on Whale Safe, a publicly available online map tool created by the Benioff Ocean Science Laboratory in partnership with other marine research institutions and universities that tracks live location data of both ships and whales. As warming waters change where whales forage for food, whale population locations and density are rapidly changing and regulations can’t always keep up. When it comes to predicting whale behavior, “the reality can change in a single season,” says Dr. Hazen.

While the program has by all accounts been a success, slowdowns are only half of the solution when it comes to reducing whale strikes. Jessica Morten says that, “ideally,” vessels and whales would be separated as much as possible, but that US regulators haven’t rerouted shipping lanes to protect whales since 2012, when NOAA adjusted several routes in and around the San Francisco Bay. However, this past December, a court ordered the US National Marine Fisheries Service and the US Coast Guard to reexamine California shipping lanes in response to a 2021 lawsuit filed by the Center for Biological Diversity and Friends of the Earth against the Trump Administration.

Kindberg says Maersk supports mandatory speed limits, which would provide an “even playing field” for companies already complying with slow-down requests. Researchers say while a regulated zone is likely to be less adaptable to changing whale behaviors than a voluntary one, compliance would be easier to enforce with penalties and fines.

Morten says that while the benefits to whales are harder to prove, the program has contributed to huge gains and air quality in southern California. “There’s an awesome co-benefit that exists with trying to get people to be more appreciative of the program,” says Morten. “It’s not just for whales, it’s also for air and climate mitigation.”

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