SF Bay whale migration patterns put priority on safety programs

ByDan Ashley and Tim Didion via KGO logo
Saturday, October 15, 2022
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A researcher at the Marine Mammal Center who has been watching SF Bay for decades says, lately, there's been a lot more to keep an eye on.

SAN FRANCISCO (KGO) -- As a researcher at the Marine Mammal Center, Bill Keener has been watching San Francisco Bay for decades. But he says lately, there's been a lot more to keep an eye on.

"Well, the humpbacks are in this, the strait area and the Golden Gate Bridge, but the gray whales tend to go farther and even past Alcatraz," Keener explains.

He says the number of visits into the Bay by certain whale species have increased significantly.

Although, it's difficult to isolate a single cause, researchers suspect the pressure on their food sources from climate change could be having an impact. Keener says the humpbacks are often following anchovy, a phenomenon sometimes known as habitat compression. Gray whales, which typically migrate between Mexico and Alaska, may be facing other pressures.

"Some of them, we noticed, were starving, they were actually so hungry," he says. "They were coming into the Bay and looking for food. There's not much in the Bay for them. Normally, they feed way up north and Alaska. But they were pausing here in the Bay for days at a time."

A recent study by the National Oceanic and Atmospheric Administration found the overall gray whale populations along the coast dropping significantly. And in the last decade researchers have been documenting a variety of threats to whales tied to everything from food migration to human behavior.

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In response, agencies including NOAA, have put a priority on keeping the visiting whales safer -- especially in the crowded shipping channels that run along our coastline.

Danielle Lipski is research coordinator with NOAA and the Greater Farallones Cordell Bank National Marine Sanctuaries. The group has been monitoring whale populations with the help of a buoy-based system that literally allows them to eavesdrop, then retrieve the recordings.

"When they're vocalizing whales in the area, and we can hear them, we listen to them," explains Lipski. "And so what this has illuminated for us is that there are whales in the region for a lot longer than we thought. Humpback whales are pretty much here year round. And the season for blue whales and fin whales is also longer than we thought."

She says that data is combined with ocean surveys to inform the agency's Ship Strike program, which asks shipping companies to slow down in areas where multiple species of whales are vulnerable.

"So this year, partially based on that information, we extended our voluntary speed reduction request to be longer in the year, so we extended until December this year. And next year, starting in 2023, we're going to be looking to extending that even further," she says.

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And that surveillance is getting an added layer as well. Several weeks ago, we watched a demonstration of a new monitoring system called Whale Safe, deployed in a collaboration by the Marine Mammal Center and Benioff Ocean Science Laboratory. It's able to transmit real-time updates, including the speeds of nearby ships.

Back in the Marin Headlands, Keener is concerned both about the safety of the whales, and better understanding the potential changes to their complex ecosystem.

Learning whether the shifting patterns in feeding and migration are temporary, or a longer-term effect of climate change or other factors.

"Well, I think everything's changing out in the ocean. And so before 2016, we didn't see humpbacks coming into feed. So I think things could go up and down over the years so that we might get more in some years and lessons and other years," Keener believes.

These unpredictable changes could ultimately force humans to adapt our behavior along with the whales.

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