NOAA: Oceanic acidity caused by climate change could affect Alaska crab numbers

ANCHORAGE – Oceanic acidification caused by climate change could cause a decline in numbers of Alaska crab species, according to new studies from National Oceanic and Atmospheric Administration, officials announced in a press release Tuesday.

60 percent of U.S. seafood comes from Alaska and a profitable portion comes from crab fisheries. The acidic conditions in ocean water could affect crabs on varying levels depending on a crab’s age, according to NOAA official, Chris Long.

“The ocean environment that larval Tanner crabs live in is highly dynamic, with variable levels of acidity,” said Long. “At this age, tanner crabs seem able to tolerate shifts in pH. But if these animals are exposed to more acidic conditions at the embryo stage, they may be less able to tolerate changes in ocean acidification as larvae.”

Young crabs exposed to low pH levels do not accumulate calcium well which makes them more vulnerable to predation and that fewer crabs would make it to adulthood.

A separate study on blue king crabs revealed slower growth rates and higher mortality in juveniles exposed to more acidic conditions. The blue king crab populations around Pribilof Islands and St. Matthew Island areas have fluctuated dramatically, officials say.

“This suggests that environmental conditions play a big role in the number of young crabs that actually grow to maturity and can be caught by the commercial fishery,” officials wrote. “Changes in ocean acidification may make it even more difficult for these populations to recover from recent low levels.”

Bob Foy, head of the Kodiak Lab for Alaska Fisheries Science Center says the situation doesn’t look good. Based on the research, unless crabs are able to adapt to the changing conditions, officials say Alaskan fishermen will see a drastic drop in crab numbers within the next 50 years.

Kendall Bautista, KTUU, 1 March 2016. Article.

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