Shaun Chadburn, environmental programs coordinator for North Cowichan, said in response: “We regularly monitor water quality in the lake and we have observed a few dead fish over the past weeks so this doesn’t came as a huge surprise. 

“The lake has/or is still in the process of ‘turning over’ and as a result,  the dissolved oxygen has been steadily decreasing to near zero throughout the water column. 

“We have one of our regular sampling events scheduled to occur next Tuesday which will likely confirm that dissolved oxygen levels have decreased to a state where fish can no longer survive.
 
“Unfortunately, there isn’t much we can do to mitigate the current situation, but as you likely know, we are looking to do a trial of an aeration system in 2026.

“Hopefully this trial will show some positive results and lead to us closer to installing a lake-wide aeration system which will help to remediate the lake and avoid this in the future.”

Read more background: https://www.cowichanvalleycitizen.com/home/north-cowichan-aims-to-improve-somenos-lake-water-quality-following-fish-kill-7742227
 
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— Larry Pynn, Sept 19, 2025.