As blue king crab fisheries continue to struggle in the Bering Sea, another stock has been added to the nation's "overfished" list.
Every year, the National Oceanic and Atmospheric Administration (NOAA) reports to Congress on the status of U.S. fisheries. The report highlights which stocks are in "overfishing" and "overfished" status, as well as which stocks have been rebuilt.
Krista Milani, a natural resource specialist with NOAA Fisheries in Unalaska, said the 2018 report, released in August, shows the number of U.S. fish stocks subject to overfishing remains at a near all-time low. That means there are a lot of healthy, sustainable populations, but it's not all good news.
"For the Alaska region, we didn't have any fisheries that were in overfishing status, but we do have two stocks that are considered overfished," said Milani.
One of those is Pribilof Island blue king crab, which has been designated as "overfished" since 2002. The other is the newly-added blue king crab stock around St. Matthew Island, north of the Pribilofs in the Bering Sea.
Milani said there's an important distinction to make when it comes to stock status. If a stock is experiencing "overfishing," humans are responsible for catching too many of the species. But if it's been designated as "overfished," that doesn't necessarily mean overfishing has occurred.
"For blue king crab, we're fairly certain that they're declining due to environmental conditions," said Milani. "Things like warmer water, ocean acidification, changing ocean currents — all those things can affect a blue king crab's ability to reproduce and for larvae to mature to adult crab, which affects overall biomass of the stock."
NOAA has two years to develop a rebuilding plan for the St. Matthew stock. Milani said that could include reevaluating the agency's management strategies or closing certain fishing areas to avoid blue crab bycatch.
"The rebuilding plan [should] go into effect in 2020," she said. "From the start of that rebuilding date, the Magnuson–Stevens Act gives us 10 years to declare the stock 'rebuilt.'"
That timeline doesn't always work. For instance, the Pribilof blue king crab stock has been "rebuilding" since 2004, and it's still considered overfished.
Milani said many crab populations in the Bering Sea/Aleutian Islands region have been declining over the past few years, and it's hard to pinpoint exactly why.
At its peak in the 1980s, the St. Matthew fishery harvested nearly 9.454 million pounds of blue crab each year, according to data from NOAA and the Alaska Department of Fish and Game. In 2015-16, the catch was down to just 105,000 pounds.
Going forward, Milani said there's no doubt scientists will have to study climate changes more and more to determine how Alaska's fish stocks will fare in the future.
Other species added to the 2018 "overfished" list include coho salmon in the Washington's Puget Sound, chinook salmon in California's Klamath and Sacramento rivers, and Atlantic mackerel in the Gulf of Maine.