Citizen science website Zooniverse is asking people to look through images online that have been taken on the westernmost Aleutian Islands and classify them.
About 400,000 photos are captured each year from 20 remote cameras.
The Steller sealion population in this location has declined in the past 30 years by 94 per cent.
Experts are hoping to discover why by following the lives of certain individuals.
"This research is important to figure out why the endangered Steller sealion is not recovering in the Aleutian Islands," said Katie Sweeney, a biologist with NOAA Fisheries, which has gathered the images and is undertaking the research.
"This is the best way we can estimate important population rates and to accomplish this in a timely manner, we're asking for the help of citizen scientists."
The islands are so remote that the cameras are accessed only once a year by the researchers.
Less than five per cent of sealions are permanently marked with a combination of letters and numbers, allowing the researchers to identify these individuals throughout their lives.
Volunteers for the citizen science project are being asked to look through the pictures and identify those that feature marked sealions.
"It's great to be able to share our research on Zooniverse and engage with the public," said Sweeney. "They're helping us out immensely and making great headway on the images! We have hundreds and thousands of more to come!"
Find out how you can get involved with Steller Watch.
