Dungeness Crab in Peril (by Dylan Escobar)
Ocean Acidification could cause the Dungeness crab fishery to decline throughout the West Coast, a new study has found, threatening a fishing industry worth nearly a quarter-billion dollars a year.
Scientists in Seattle found that at current rates of greenhouse-gas pollution the pH levels predicted in West Coast ocean waters by 2100 would hurt the survivability of crab larvae.
Already scientists knew that increasing ocean acidification is predicted to harm a wide range of sea life unable to properly form calcium carbonate shells due to the pH drops. Now for the first time, scientists have also predicted that animals with chitin shells — specifically Dungeness crabs — are affected, because the change in water chemistry affects their metabolism.
That in turn likely would cause a decline in the population of a fishery that is of economic importance to tribal and nontribal fishers alike. The total value of the 2014 Dungeness crab catch in Alaska, California, Oregon and Washington was $211.5 million, according to data provided by NOAA fisheries.
The crab fishery is of great cultural importance, too, a birthright of tribal and nontribal Northwest residents for whom fresh-caught Dungeness crab defines part of what it means to live here.
Crab larvae also are an important food source for a wide range of sea life, including salmon.
Dungeness crab, Cancer magister, is a denizen of coastal and Puget Sound waters. Adults occur in the inshore waters where pH today in summer can be as high as 7.6, but in the future, are predicted to lower to 7.1.
Other fish species have been found to be harmed by acidifying waters, including clown fish, which mistake predators for prey as pH plummets.
While effects predicted in the research are forecast for the year 2100, levels of acidification could plunge lower sooner, depending on whether levels of greenhouse-gas pollution are brought under control ("NOAA: Dungeness Crab in Peril from Acidification", 2016).
Greenhouse-gas pollution is expected to reduce the survival of crab larvae.
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