[Wednesday] will bring."
Scientists have been warning all month that oxygen conditions in Hood Canal are the worst they’ve seen in years and could at any moment lead to the suffocation of tens of thousands of fish.
Twice last week, hundreds of creatures washed up dead on the canal’s shores, but oxygen levels improved before things grew worse.
On Monday poor conditions returned with a vengeance, and researchers were bracing themselves for wholesale marine death.
But late Tuesday, Tony Parra, a marine biologist with the Washington Department of Fish and Wildlife, and other divers went back underwater again, where things had slowly begun to improve.
Fish still clustered near the surface, straining to capitalize on a slight increase in oxygen brought about by a shift in the wind.
A single white spotted greenling appeared to have suffocated, and wolf eels and other fish were still panting. But, for the moment, the worst seemed to be over.
For more than a decade, natural conditions and increasing pollution have led to recurring bouts of low-oxygen in Hood Canal. That oxygen-depletion results in a floating dead zone that has at times killed thousands of fish, most notably in 2003 and 2006.
The problem comes at the end of summer after algae blooms, nourished by nitrogen from sewage and other runoff, die and decompose in the southern part of the canal. That uses up oxygen throughout much of the water column. That "hypoxic" water is eventually flushed from the canal.
But last year much of that dangerous water stayed in the canal and has now been compounded by another summer of algae growth. This year that low-oxygen zone sometimes stretches vertically through more than 150 feet of water, and has pushed most of the fish to the surface.
Through the night Monday, strong south winds pushed the surface waters north, allowing poorly oxygenated water from below to take its place, leaving nowhere for the fish to go.
"I don’t know how anything can survive right now," diver Janna Nichols said Tuesday. She’s a volunteer who shot underwater photographs and video Monday and returned Tuesday to take a second look. Monday, "I saw an octopus die right in front of me. I saw it breathe, and then it stopped, just like that. And it’s definitely worse today."
By late afternoon Tuesday, the wind had shifted to the north, which brought fresher water back into the canal.
Measurements taken from research gauges late in the afternoon showed oxygen levels in and around Hoodsport had increased from one milliliter per liter to about two milliliters. Anything below five is stressful for fish respiration; below two is considered lethal.
Scientists remain sufficiently concerned that they planned to be out working through the night Tuesday, monitoring beaches with flashlights to keep tabs on any fish mortality.
The concern is that Wednesday’s 3:15 a.m. minus tide, the biggest in 24 hours, could strand the seriously weakened fish near shore.
"We may see lots of fish dying overnight, or maybe no fish die — hopefully that’s the case," Parra said.
Either way, "chances are pretty good that I won’t be getting much sleep."
Craig Welch: 206-464-2093 or firstname.lastname@example.org