UPDATE: Sept. 24, 2010
Conditions have remained pretty much the same the last couple of days, although the intrusion of dense higher-oxygen water from the ocean is beginning to create a thicker layer at the bottom of Hood Canal. The middle layer of low-oxygen water remains fairly thick, but the upper layer with higher oxygen concentrations is still providing fish some relief. South winds remain a threat, as I’ve explained for the last few weeks.
One can observe the three layers in the upper graph. The lower
graph shows changes over the past week or so. Notice how oxygen
concentrations are rising in the deep layer.
Fish in southern Hood Canal got a little more room to breathe this morning, as oxygen levels rose in the top 30 feet of the water column.
I described the latest observations from researchers in a story published this morning on the Kitsap Sun’s website. A story written for today’s Kitsap Sun also contains some important observations about events of the past two days.
The rapid recovery may have been largely the result of a seiche, in which waters pushed away by winds came back when the winds ceased. In terms of the overall conditions, nothing major has changed, however, and south winds could trigger another fish kill.
One thing I found interesting but disturbing was that many of Hood Canal’s famous spot prawns were making a deadly choice. They were swimming into freshwater inlets, where the waters were more oxygenated, only to die when they could not survive the low salinity. I understand that the greatest losses were at the outlet of the lower Cushman Dam at Potlatch, where waters from the North Fork of the Skokomish River come into Hood Canal.
Here’s how the oxygen levels have changed at Hoodsport
since 11 o’clock last night and 10 o’clock this morning. Note the
blue line, which is about the 9-foot level, as measured by a
monitoring buoy that operates around the clock.