Pacific ‘dead zone’ worse than thought

PORTLAND – Scientists say the oxygen-starved “dead zone” along the Pacific Coast that is causing massive crab and fish die-offs is worse than initially thought.

Scientists say weather, not pollution, appears to be the culprit, and no relief is in sight. However, some say there is no immediate sign yet of long-term damage to the crab fishery.

Oregon State University scientists looking for weather changes that could reverse the situation aren’t finding them, and they say levels of dissolved oxygen critical to marine life are the lowest since the first dead zone was identified in 2002. It has returned every year.

Strong upwelling winds pushed a low-oxygen pool of deep water toward shore, suffocating marine life, said Jane Lubchenco, a professor of marine biology at OSU.

She said wind changes could help push that water farther out but current forecasts predict the opposite.

After a recent trip to the dead zone and an inspection via camera on a remote-controlled submarine, Lubchenco said, “We saw a crab graveyard and no fish the entire day.”

“Thousands and thousands of dead crab and molts were littering the ocean floor. Many sea stars were dead, and the fish have either left the area or have died and been washed away,” she said. “Seeing so much carnage on the video screens was shocking and depressing.”

The effect on the commercial fishery isn’t yet known, said Hal Weeks, a marine ecologist with the Oregon Department of Fish and Wildlife.

“The last two years have been record-breaking years in Oregon for Dungeness crab” despite dead zones, he said.

“In that fishery there has been no apparent effect. That doesn’t mean there won’t be,” Weeks said.

It is Oregon’s most valuable fishery, worth as much as $44 million in recent years.

But Weeks said crab populations fluctuate wildly for reasons not well understood. Whether any harvest decline is a result of normal fluctuation or the effects of the dead zone is hard to say, he said.

He said some reports indicate the loss of fin fish may be due to movement to areas with more oxygen rather than mortality.

Al Pazar, chairman of the Oregon Dungeness Crab Commission and a crab fisherman out of Newport, said this season is shaping up to be the second-best ever, around 28 million pounds, but that most crabs are caught in the six or eight weeks following the season’s winter opening, well ahead of the appearance of the dead zones.

Oregon State scientists working with the Oregon Department of Fish and Wildlife used a remote-control device Tuesday to check biological impact and continue oxygen sampling.

Dissolved oxygen readings off of Cape Perpetua north of Florence are between 3 percent and 10 percent of levels needed for survival and near zero in some areas.

Similar but lesser zones have been found elsewhere along the Oregon and Washington coasts. Scientists say they don’t yet know how widespread it is.

There are no seafood safety issues, OSU experts say. Only live crabs and other fresh seafood are processed for sale.