Sea lion scientists need your help.
Each summer, researchers from National Oceanic and Atmospheric Administration (NOAA) Fisheries in Seattle trek to Alaska’s remote Aleutian Islands. They take small boats to rocky beaches to tag Steller sea lion pups. They fly planes and deploy hexacopter drones to capture images of the beached behemoths. Cameras mounted on shore snap even more photos.
Their job is to solve the mystery of the precipitous decline of the creatures. The largest sea lions in the world, an adult male Steller sea lion can weigh 2,500 pounds — nearly as much as a compact car.
“You’re on these spots that very few people get to go see, around hundreds of animals that could rip you apart if they wanted to,” said Lowell Fritz, a research fishery biologist with NOAA Fisheries.
Not to worry. The assistance that the researchers are seeking can be done from the safety of your own home or office, with no risk of a sea lion mauling. What the federal scientists need is help analyzing the thousands of sea lion images collected each year.
“We’re hoping someone can create sea lion recognition software,” said Fritz, who works for the agency’s Alaska Fisheries Science Center, which is based in Seattle.
Identifying the sea lions in the photos provides essential data for saving the animals. It gives insights into the overall population size, their birth rates and age at reproduction, and survival at different ages.
Some photos of sea lions are easy to tally, but in others the animals cluster in a big blob.
“It’s a tricky problem,” he said. “When you look at it by eye, you can see it’s 10 sea lions. When a computer does it, it’s a little harder.”
So last week the researchers opened a competition on Kaggle, a data science website, seeking an individual or team who can build software to successfully count the sea lions. There are already 40 participants competing for a share of $25,000 in prize money.
The scientists believe that about 13,000 Steller sea lions live in the Aleutians, which are volcanic islands that stretch from Alaska to Russia. Only a few thousand people live there. An additional 52,000 Steller sea lions live in the area that includes Prince William Sound, Kodiak Island, the Shumagin Islands and the eastern Bering Sea.
In the Aleutians, their numbers have been slipping since at least the 1970s and ‘80s. Twenty years ago, the western stock of Steller sea lions was federally listed as endangered, meaning they’re at significant risk of extinction.
But while populations in the rest of Alaska have shown an increase in recent years, the Aleutian sea lions have not. In fact, their numbers are down 95 percent from what they were in the ‘80s. And there is no sign of recovery.
Researchers don’t know exactly why that is. They suspect that the decline in sea lion prey, including mackerel, cod, salmon and squid, might be playing the largest role. The scientists are also finding elevated levels of toxic mercury in the pups. Orcas hunt some of the sea lions as well.
Sea lions are very habitual, returning each year to the places they were born to give birth to the next generation of pups. But scientists have been alarmed to find that formerly popular rookeries are now abandoned.
“There are no pups born there anymore,” Fritz said. “That’s one of those things where you go, ‘Wow, that’s rare to see.’”
The photographs helped the researchers identify the vanished rookeries. They’re monitoring 450 sites through aerial photography, hitting half the locations each summer. Annually, they gather 40,000 images this way.
The female sea lions return to the rookeries in late May and early June to have their pups. They mate again about a week later. (In an interesting biological quirk, three months pass before the fertilized sea lion egg implants in the mother. Once it does, the fetus grows for nine months, ensuring that the pups will be born at the same time each year.)
It takes two people up to four months to process the aerial photos by hand. They place paint balls on each sea lion using Photoshop, with different colors according to age and gender. The researchers could retire that tedious process if the Kaggle contest is a success.
Engineers have until June 20 to enter the Kaggle competition. June 27 is the final submission deadline.
In addition to the aerial images, the NOAA Fisheries scientists collect even more photos of the sea lions from 20 remote cameras mounted near beaches favored by the marine giants.
During daylight hours, the cameras snap an image every five to 20 minutes year-round. The exercise produces approximately 400,000 images annually. Each photo is then split in two to increase the resolution and analyzed.
But the success of the program, which started in 2012, created a backlog of hundreds of thousands of images needing analysis.
A month ago, the scientists started a campaign on a site called Zooniverse, which is billed as “the world’s largest and most popular platform for people-powered research.” The researchers are asking volunteers to help them sift through the images, chucking those that don’t contain sea lions and noting those that show sea lions that they’ve tagged by branding them.
About 3,500 volunteers have participated in the Zooniverse project, retiring about 98,000 images that lacked sea lions. An additional 750,000 images have been uploaded by the citizen scientists with details about tagged animals.
To tag the sea lions, researchers visit the rookeries when the pups are about a month old. They anesthetize the pups and hot brand them with numbers and symbols measuring about 3 inches tall. Two veterinarians are part of the process, and the pups are monitored to make sure they recover from the anesthesia and reunite with their mothers. The pups are about 70 to 110 pounds when branded, and as they grow, the markings grow with them.
The scientists only brand half of the pups at any given site, and a team of 10 can tag up to 100 sea lions in a day.
“It’s a rodeo,” Fritz said, “but it is a lot of fun.”