(Bloomberg) -- Helping the canned tuna industry cope with climate change tops an already lengthy to-do list for Darian McBain, chief sustainability officer at the Thailand company that owns the Chicken of the Sea and John West brands.

In a business long accused by activists of abusing workers and killing dolphins, McBain’s responsibilities at Thai Union Group Pcl typically focused on improving labor rights in the supply chain and reducing the abandoned fishing gear on the high seas.

“Climate change hasn’t been the No. 1 topic,” she said. “Now, the climate emergency has to be a lot stronger part of the dialogue.”

The industry hasn’t yet confronted the magnitude of the problem, McBain said.

“In five years’ time, maybe the tuna won’t be in the oceans we thought they would be,” she said. “Will it be economic to catch those species? These are issues too big for one company to solve on its own.”

For now, Thai Union is looking at what it can do itself. That means reducing carbon emissions from its facilities and boosting efforts to protect coastal ecosystems and ocean fisheries. And in a world with a limited supply of wild-caught fish, the company is hedging its bets by investing in alternative proteins.

There’s a lot riding on protecting the industry. The four major types of tuna generate at least $42 billion in revenue (nearly 30% of the world’s seafood industry) and provide protein to 3 billion people, according to the Pew Charitable Trusts.

But about 18% of the world’s commercial tuna stock is overfished, the International Seafood Sustainability Foundation said in a March report, with 65% at a healthy level and the rest in between. Bluefin tuna, popular with sushi eaters, is one of the most endangered, although fisheries for skipjack (the main type sold on supermarket shelves) still were healthy.

Thai Union makes one of every five cans of tuna worldwide, and its sales of products on supermarket shelves totaled about 55.2 billion baht ($1.7 billion) last year, more than 40% of total revenue.

The company is getting a bump from the coronavirus pandemic as worried consumers stockpile cans of tuna. Shares rose more than 12% in the week ending March 20.

McBain, 46, earned her Ph.D. in supply-chain analysis from the University of Sydney and formerly worked for the U.K.’s National Health Service. She joined Thai Union in 2015 when it was under siege from environmentalists and human-rights groups. The company now works with non-governmental organizations, including Greenpeace and WWF, to implement labor reforms and improve sustainability standards.

In 2018, Thai Union announced a partnership with California’s Monterey Bay Aquarium to work on sustainability projects.

“Trust has been established,” said Jennifer Dianto Kemmerly, who oversees the aquarium’s Seafood Watch program. “We all have the same end goal, which is to help the ocean.”

Thai Union ranks first among 30 companies in the Seafood Stewardship Index, a grading by the World Benchmarking Alliance of corporate policies toward supply chains, ecosystems and working conditions. Rivals Bumble Bee Foods ranked 16th and StarKist owner Dongwon Group of South Korea ranked 19th.

Thai Union has 10 partnerships called Fishery Improvement Projects (FIPs), in which the company works with suppliers and non-profit groups to manage fisheries and move toward receiving third-party sustainability certification. That’s an important seal of approval for many retailers in the U.S. and other countries.

Within five years, Walmart Inc. will require canned tuna sold in its U.S. stores to have sustainability certification or come from an FIP with “definitive and ambitious goals, measurable metrics, and time bound milestones,” according to a policy statement. Aramark, which provides food to schools, businesses and sports arenas, only buys canned tuna that meets Seafood Watch’s standards.

Other seafood companies formed FIPs, too, but Thai Union stands out, said Blake Lee-Harwood, strategy director of the Sustainable Fisheries Partnership, a non-profit that works with companies in the seafood supply chain such as Tesco Plc and McDonald’s Corp.

“They are the most progressive,” Lee-Harwood said. “They seem to be the best-in-class at the moment.”

Warmer oceans threaten to disrupt that progress. Ocean temperatures last year “were the warmest in recorded human history,” according to a recent paper by scientists in the U.S. and China.

Because of climate change, certain parts of the ocean also may contain less oxygen, posing another risk to fish. Schools of tuna likely will change their migratory patterns, many policy makers and environmentalists say, and that could jeopardize long-established fisheries where companies get much of their supply.

“You have a whole new set of sustainability issues that companies are going to have to deal with,” said Timothy Fitzgerald, a director at the Environmental Defense Fund in Washington. “As climate change takes hold, the population will be shifting toward an area that is less well-managed: the part of the ocean that doesn’t belong to anybody.”

Even as they try to address these problems, McBain and Thai Union are taking hits on some of the issues they tried to put behind them. In the U.S., critics question the assertions on Chicken of the Sea labels that the production process doesn’t harm dolphins swimming near the tuna. The Thai Union brand isn’t dolphin-safe, according to a lawsuit filed in California in May.

Attorneys for the plaintiffs declined to comment.

Thai Union is fully compliant with U.S. rules regarding dolphins, McBain said.

“As a listed company, our imperative is to comply with regulations,” she said. “We have gone beyond that and are in the process of continuous improvement.”

To address climate change, the company is focusing on ways to reduce carbon emissions, including from suppliers, she said. Thai Union also will consider putting resources into the protection and restoration of mangroves and other coastal ecosystems important for many fisheries.

McBain is, in many ways, an outsider at Thai Union. She’s an Australian woman at a Thai company with an all-male board. And at a company that makes so much of the world’s packaged tuna, she’s a vegetarian.

Thai Union is moving in new dietary directions, though, launching a $30 million fund to invest in innovations such as alternative protein sources. It’s already backing startup Flying Spark Ltd., which makes food from the larvae of fruit flies.

Climate-change strategies should focus on innovation, she said, since the fishing industry is close to maximum catch levels. The old adage about there being plenty of fish in the sea isn’t so accurate anymore.

“You won’t be getting more fish out of the ocean,” McBain said.

©2020 Bloomberg L.P.