Ocean acidification threatens NW oysters

Posted NWCN.com: July 10, 2012 — By King 5 News


The world’s top marine scientists are meeting this week in Australia to discuss what many are calling the greatest threat so far to the survival of our oceans – acidification. It’s a problem that’s already attacking one the Northwest’s greatest resources: its oysters.

Local commercial growers like Taylor Shellfish are spending every day trying to create healthier water for their oysters. They’ve seen what acidification has done to others in the shellfish industry.

“There have been huge die-offs. There’s been a large inability to produce oyster larvae,” said Katie Schaffnit, hatchery research technician

Acid levels go up as the ocean absorbs excess carbon dioxide, the ph levels then drop and tiny oysters  lose the ability to produce what every oyster needs to survive: its shell.

“The ultimate goal is to increase ph levels and decrease CO2 from the water. We’ve tried sodium hydroxide, we’ve experimented with sodium carbonate and right now we’re working with a natural algae treatment,” said Schaffnit.

Algae is nature’s filter system and may offer a cheaper, more natural way of controlling carbon dioxide and acidification.

“Because when algae or sea lettuce, as many people call it, is exposed to daylight, in undergoes photosynthesis and works like a tree and absorbs carbon dioxide, which is bad for oysters, and replaces it with oxygen, which is good,” said Schaffnit.

The experiment is only a few weeks old, so it’s too early to tell if the method is a success.  The water Taylor uses in Hood Canal doesn’t have dangerously high acid levels yet, but something is affecting the crop.

“Our production this year is much slower than it was last year. The larvae are growing much more slowly,” said Schaffnit.

Ocean acidification has gotten so bad for one commercial shellfish grower in the Northwest that they’ve decided to move their hatchery operations to Hawaii, where the levels are lower. Taylor hopes to avoid that by coming up with natural methods to control it.
KING 5’s Gary Chittim and Liza Javier contributed to this report