Ocean Acidification Threatens Shellfish Hatcheries

New research paints an unsettling picture of the future of shellfish in coastal Alaska. The effects of ocean acidification are worsening and could mean the end of hatcheries in the next 25 years if costly mitigation efforts aren’t put in place.

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Two-thousand forty – that’s the year put forward by researchers in the ongoing study.

“It is dire,” says Wiley Evans, a research associate at the NOAA Pacific Marine Environment Lab in Seattle and the University of Alaska Fairbanks Ocean Acidification Research Center. He led the project, based at the Alutiiq Pride Hatchery on the Kenai Peninsula. Right now, the hatchery has only a 5-month window where ocean conditions are right for production.

“It was very, very alarming. Not knowing much about ocean chemistry, I know a lot more now than when we started, that’s for sure,” says Jeff Hetrick, owner of Alutiiq Pride shellfish hatchery, which is situated at the head of Resurrection Bay in Seward.

“Right now we have blue and red king crab, roughly 6 million

Beach clams. Alaska Public Media stock photo.
Beach clams. Alaska Public Media stock photo.

sea cucumbers, 2 million cockles, 7 million little neck clams, 100,000 butter clams, roughly 300,000 purple-hinge rock scallops, abalone as well, and we have oysters and geoducks, too.”

It’s currently the only full-time commercial shellfish hatchery in the state, with on-site personnel, which made it a logical choice for data collection.

Jeremy Mathis is a NOAA oceanographer who helped choose the site.

“We had the opportunity last year to install a state-of-the-art system that could monitor the water chemistry of the seawater that they were pumping in to the hatchery on a continuous basis and it would report out to us in what we call real-time,” Mathis says.

Ocean acidification is the name for certain changes in the ocean’s chemistry due to higher levels of carbon dioxide. When seawater absorbs CO2, there’s an increase in hydrogen ions, leading to more acidic water, and lower levels of carbonate ions.

Carbonate ions are crucial for organisms like clams and mussels to develop hard shells. And, without shells, they aren’t protected and can’t survive.

Mathis says Resurrection Bay is in a particularly vulnerable position because of certain environmental factors.

“It gets a lot of freshwater input from not only the streams and little freshwater runoffs that come through there but also quite a bit of meltwater from glaciers. And that unique water chemistry can actually exacerbate or worsen the ocean acidification effect.”

Cold water, which is quicker to absorb CO2, combined with the presence CO2-rich glacial melt put Alaska as a whole at particular risk. Evans says those factors are natural and it’s a delicate balance. But as for the levels we’re seeing here now-

“It’s not natural and it’s a large problem,” Wiley says.

Humans and their carbon footprint have added serious amounts of CO2 to the atmosphere very quickly.

“And that little bit of additional carbon dioxide can just push the system past thresholds to where you can’t produce shellfish perhaps anymore without very serious mitigation strategies,” he adds.

That’s what worries Hetrick when he thinks about the future and the 5-month production window at his hatchery that’s on track to close completely in 25 years.

“We don’t really know what the full costs are going to be. There’s going to be some. There’s going to be capital costs and there’s going to be some operational costs. It’s just going to be another thing we’re going to have to do to produce shellfish.”

Figuring out exactly what to do next is tricky but Mathis says, Alaska has to put in the effort, immediately.

“Unfortunately, Alaska is the canary in the coal mine for ocean acidification. We’re seeing changes in water chemistry faster in Alaska than really any other place around the world. So, it’s our job now in the next few years to figure out what the magnitude and impact of those changes are going to be.”

And he says, find a way to protect our fisheries before it’s too late.