May 19, 2016 — The Dungeness crab fishery could decline West Coastwide, a new study has found, threatening a fishing industry worth nearly a quarter-billion dollars a year.
Scientists at the Northwest Fisheries Science Center in Seattle found that pH levels likely in West Coast waters by 2100 at current rates of greenhouse-gas pollution would hurt the survivability of crab larvae.
Increasing ocean acidification is predicted to harm a wide range of sea life unable to properly form calcium carbonate shells as the pH drops. Now scientists at the NOAA’s Northwest Fishery Science Center of Seattle also have learned that animals with chitin shells — specifically Dungeness crabs — are affected, because the change in water chemistry affects their metabolism.
Carbon dioxide, a potent greenhouse gas, is pumped into the atmosphere primarily by the burning of fossil fuels. Levels of atmospheric C02 have been steadily rising since the Industrial Revolution in 1750 and today are higher than at any time in the past 800,000 years — and predicted to go higher.
When carbon dioxide mixes with ocean water it lowers the pH. By simulating the conditions in tanks of seawater at pH levels likely to occur in West Coast waters with rising greenhouse gas pollution, scientists were able to detect both a slower hatch of crab larvae, and poorer survival by the year 2100.