Studies uncertain on how adaptable Alaska crab species are to ocean acidification

Ocean acidification is bringing uncertainty about the future to Alaska’s crabbing industry.

That’s according to the findings of two recent studies from the National Oceanic and Atmospheric Administration that examined the effects of acidification on Tanner and blue king crab in the state’s waters.

One of those studies found Tanner crab larvae were able to withstand shifts in ocean acidity but didn’t survive so easily if they were exposed to more acidic waters as embryos, an Alaska Fisheries Science Center report on those studies said.

The other study of juvenile blue king crabs over about a year found they were eventually able to adapt to acidic seawater. Though about 60 percent of the blue king crabs in the study died in the first 100 days of the study, none died in the next 200 days.

“What that means is the crab is able to adjust its body chemistry to adapt to the environment,” said Chris Long, a NOAA researcher in Kodiak who worked on both studies. “So that’s really interesting.”

Those blue king crabs did, however, have slower growth rates after being exposed to acidic conditions.

Ocean acidification is particularly strong in waters off Alaska. More acidic water more easily dissolves calcium carbonate, which is what the shells of many marine creatures are made of. The softening of shells in young crabs also makes it easier for them to become prey, the report said. That means fewer would make it to adulthood, populations would dwindle, and there would be less stock for fishermen to catch.

“It’s not cause for panic yet, but it’s certainly not good news for Tanner crabs,” said Long. “My theory is that this will happen over the next decades, centuries. It will be gradual and give populations time to adapt.”

These two studies are part of ongoing work about ocean acidification and crabs by NOAA in Alaska and the University of Washington.

UW researcher André Punt, who is using these studies to understand the eventual effect of ocean acidification on the crabbing industry, said in the report that crabbers can expect lower catches in the next 40 to 50 years if crabs don’t adapt to acidifying waters.

And that’s not just significant for Alaska. The rest of the U.S. also gets about 60 percent of its seafood from the state, the report said.

Annie Zak, Alaska Dispatch News, 2 March 2016. Article.


  • Reset

Subscribe

OA-ICC Highlights


%d bloggers like this: