Kokanee in Peril

The Canadian Broadcasting Corporation has just released a story about the decline of the Kokanee fishery in the Okanagan’s Wood Lake this year. In short, local fishermen have been unable to find kokanee this year in this, the most productive kokanee lake in the entire region. Here’s the story. The story is now going viral on the Internet.

Kokanee Fishing on Wood Lake Source

But the fish aren’t here.

Since the beginning of the series of explorations called Okanagan Okanogan I have been concerned with the alterations that human society has made to the natural water systems of the Okanagan, by diverting water flows from natural systems and piping water through homes, sewers, and water purification plants instead. Perhaps what we are seeing is the consequence of this behaviour. During the 1970s, for example, when large algal blooms were threatening the health of Wood Lake, the Hiram Walker Distillery on the shores of Wood Lake saved the day by diverting large volumes of clear Okanagan Lake water into their plant, and then flushing it out again through Wood Lake. As a result, the length of time water remained in Wood Lake was reduced by 50% and the danger of excessive algal bloom and its subsequent consumption of all the oxygen in the cool, lower layers of the lake, was avoided. Now the bloom is back, and the fish aren’t. A similar crash happened in the Kootenay Lake system in the 1980s, when the productivity of the lake, destroyed by upstream dam construction in the 1920s was mitigated by runoff from a fertilizer plant, which kept the lake alive. When the plant was required to meet new pollution requirements, the lake died. The solution is to fertilize the lake annually with chemical fertilizers. You can read this amazing story here.

Don Gayton’s Redfish

Salmon that never go to sea

In the case of Wood Lake, it looks like the solution might be to return water flow to the lake, as opposed to just mechanically or chemically managing the algae. No matter how it works out, it’s good to remember that algal bloom is just a symptom of water abuse. It also is becoming clear that in the mountains on this shore of the Pacific, kokanee are like canaries in a coal mine.

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