Oxygen levels improve in Hood Canal past few days

Fish and other sea creatures are finding some room to breathe in southern Hood Canal as higher oxygen levels have returned to the upper portion of the waterway after things looked pretty bleak on Monday. See Water Ways post.

I reported yesterday that fish could safely go down to 60 feet in a story posted on the Kitsap Sun website, but conditions are changing all the time. Now it looks like the cutoff depth is closer to 50 feet, while waters closer to the surface appear to be more oxygenated than yesterday.

I discussed the situation with Dan Hannifious of the Hood Canal Salmon Enhancement Group and included some of Dan’s comments in the story. Rather than repeat those comments here, I’ll let you click on the story.

What I did want to share are a couple graphs that show current conditions as of 9:30 this morning. Most of the real-time analysis comes from monitoring buoys in Hood Canal.

This is a profile of the oxygen levels from the surface down to the bottom of Hood Canal, or close to it. The blue line is for the Hoodsport buoy, turquoise for Twanoh and green for Dabob Bay. The black line is for Carr Inlet in South Puget Sound and purple is Point Wells near Edmonds. Biological "stress" occurs at less than 5 milligrams per liter, while "hypoxia" is shown at 2 mg/l. At Hoodsport, if fish go below about 18 meters, they will be in hypoxic conditions. Earlier this week, these condition were seen at the surface.
Data from the Hood Canal Dissolved Oxygen Program.
This graph shows changes over time. While conditions have gotten better near the surface (blue line), it doesn't show much change at 66 feet (green line). As we can see in the previous graph, the changes are occurring in shallower water and will take time to reach this depth. The red line shows the intrusion of heavy seawater containing more oxygen. When comparing, remember one graph uses meters, the other feet.
Data compiled by the Integrated Ocean Observing System

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