Ships are killing whales off the California coast. Slowing down ships could save their lives

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The towering container ships and tankers that cruise in and out of San Francisco Bay have a little-known dark side: They’re a leading killer of whales migrating along the coast between Mexico and Central America and Alaska.

But there is a way to reduce the number of whales that often wash up, swollen and mangled, on Bay Area beaches this time of year, experts say. A new report recommends slowing vessel speeds along much of the coast, from Pigeon Point in San Mateo County to Point Arena in Mendocino County. The idea is to give the whales a chance to escape fatal injury.

“Most of the time sailors don’t even know they’ve hit a whale. Freighters really are like skyscrapers,” said Jessica Morten, resource protection specialist for the Greater Farallones Association, a conservation group that supports the National Marine Sanctuary of the same name. “On the surface of the ocean, a blue whale, even if it is huge for us, is really not huge.”

Morten is part of a task force tasked with reducing the risk of fatal ship strikes by 50% for endangered whales at the two marine sanctuaries that line the coast. Last month, the group – made up of scientists, conservationists and representatives from the fishing and shipping industries – recommended a voluntary year-round speed reduction at the Greater Farallones National Marine Sanctuaries. and Cordell Bank, as well as in the northern part of Monterey Bay. National Marine Sanctuary.

Since 2013, a voluntary reduction in vessel speed to 10 knots (around 11 mph) has been in place for large vessels in the three shipping lanes that exit the bay – but only from May to November, during the season of whale migration. Once ships leave the corridors, they tend to speed up and disperse into whale habitat.

The issue of ship strikes has received more attention as the number of dead whales stranded on Bay Area beaches has increased in recent years, from 11 in 2018 to 21 last year. Ship strikes are a leading cause of whale mortality, along with entanglement in fishing gear and malnutrition, according to the nonprofit Marine Mammal Center of Sausalito. The increase includes many gray whales, a population that is not endangered but is experiencing what wildlife managers call an unusual mortality event, with a high number of deaths for various reasons since 2019.

Experts say the ever-increasing demand for imported products will continue to put giant cetaceans at risk. Marine traffic has declined during the pandemic, from 3,452 ships entering the bay in 2018 to 2,893 in 2020, according to the San Francisco Bay Area’s nonprofit industry group Marine Exchange. But that’s still an average of eight large ships every day. Potential collisions are of particular concern, as there is growing evidence that some whales, particularly juvenile humpback whales, remain in the Bay Area year-round.

“We have growing populations of whales off our coasts, and we have increased shipping activity and commercial activity. So I think the risk is much higher (than in the past),” said Kathi George, task force member and director of field operations and response at the Marine Mammal Center. In partnership with the California Academy of Sciences, George and his team perform necropsies – animal autopsies – on whales that wash up on shore.

“In the case of a collision with a ship, it’s not a pretty sight,” George said. “I saw broken bones, ribs that are no longer attached, vertebrae separated. It’s a pretty violent thing that happens when a whale is hit by a ship.”

Each year, up to 83 endangered whales – humpback, blue and common whales – are killed by ships on the west coast, according to projections by the organization Petaluma Blue tip conservation science. But because their carcasses sink quickly, only a fraction are seen and reported, experts say. Additionally, dead whales often arrive on shore in a severely decomposed state, making it difficult to confirm the cause of death.

From 2011 to 2021, an average of just 10 whales a year along the West Coast were officially recorded as being struck by ships, and not all of those whales died, according to the National Oceanic and Atmospheric Administration. The list includes gray whales, minke whales and bowhead whales in addition to endangered whales.

Many of these whales start migrating around this time of year and sometimes end up dead on local beaches. George and his colleagues have autopsy supplies packed up and ready to go, like the firefighters waiting at the station. Ten to 20 people are typically involved in a necropsy, more if the whale washes up on a busy beach to help steer onlookers (and curious dogs) away from the sharp tools and hard work involved.

“A team will methodically open the whale. They will peel away the layers of fat,” George said. “Sometimes people literally go inside the whale to look at the different bones, organs, etc. to figure out what happened.”

Broken bones are a major indicator of a ship strike, but only if there are also signs of tissue damage or blood pooling inside, indicating the whale was struck before death rather than afterwards, she said.

While ship strikes are only a threat to whales, the task force believes extending the recommended speed reduction zone for ships to nearby national marine sanctuaries year-round will make a difference.

The current voluntary vessel speed reduction in the three shipping lanes that was instituted in 2013 has likely reduced blue whale deaths in the shipping lanes by 11% to 13% and humpback whale deaths by 9%. to 10% in 2016-17, according to Point Blue.

“This northern lane is really spitting traffic where we don’t want it to be,” said Morten, at a blue whale hotspot near Point Reyes.

Shipping companies board. In 2020, 64% of ships complied with the voluntary speed reduction in shipping lanes.

“We have more carriers on board – greater awareness and education as to why this is a program to participate in,” said Jacqueline Moore, vice president of the Pacific Merchant Shipping Association, an industry group that supports the extension of voluntary speed reduction. year-round area to shrines.

In 2019, a similar change was made in Southern California, when voluntary vessel speed reductions were extended to an area from Santa Barbara County to Orange County, but only seasonally. On the east coast, NOAA has instituted mandatory speed limits for ships to protect the critically endangered right whale.

The conservation group Center for Biological Diversity has called for mandatory speed limits in the Port of Los Angeles and San Francisco Bay shipping lanes in a petition to the National Marine Fisheries Service and a lawsuit against the U.S. Coast Guard and the NMFS, arguing that the number of whales killed each year exceeds what populations can sustain and still recover.

“There is a mentality of bending over backwards to avoid these mandatory ship speeds. It’s confusing,” said Brian Segee, legal director of the endangered species program at the Center for Biological Diversity. “It’s a highway at sea. Just as highways on land need rules that are enforced. It is the same with ships at sea.

The superintendent of Cordell Bank and Greater Farallones National Marine Sanctuaries will review the task force’s recommendations and likely make a decision by May, Morten said. If the changes are passed quickly, they could still save some whales next migration season, proponents say.

“Whales have a lot to tell us about the health of the ocean,” George said. “We must do what we can to reduce human impacts on whales.”

Tara Duggan is a staff writer for the San Francisco Chronicle. Email: tduggan@sfchronicle.comTwitter: @taraduggan

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