OLYMPIA, Wash. - Some of Washington state's top leaders met in Olympia Friday to discuss what a thick, gooey blob on the bottom of Hood Canal means for the marine life there.

On the surface Hood Canal shows no signs its struggle to breathe. But below the surface, its a different story. Divers this week found the bottom littered with fish carcasses. Then Skomokish tribal divers found a thick coating of mysterious goo creeping along the bottom and dozens of dead crabs coated with the substance.

Biologists knew right away what it was.

Shane Miller

Dense bacterial mats sit at the bottom of Hood Canal.

"The observation is of mats of white bacteria and what these are, they're quite common in anoxic regions, areas where there's low oxygen,” said Jan Newton, a University of Washington oceanographer.

They're called beggiotoa mats. Could this be the cause of the massive fish kill at the south end of Hood Canal this week?

Dozens or more different species were found: three different kinds of crab and three different kinds of perch. Tests show the fish are suffocating in oxygen-deprived water.

Biologists have long blamed the canal's low oxygen levels on its naturally poor circulation, and on the steady flow of leaking sewage and fertilizer from human development.

Federal divers will soon take samples of the mystery goo to determine exactly what it is and what it's doing. But if it's what scientists suspect it is, it's probably not causing the oxygen depletion it's more likely a product of it.

"The beggiatoa mats are simply a symptom showing we do have that kind of environment,” Newton said.

It’s not a cause, just another effect of a problem reaching a tipping point.

Hood Canal has suffered from oxygen-depleted dead zones for decades, but they are growing in size and duration and taking a toll on different sizes and species of fish.

The discovery of the mystery slime is apparently just one more symptom in the search for the cause.