Volunteers with the Byrne Creek Streamkeepers Society are seeing more coho prespawn mortality this season. That’s when coho that return to spawn die before they can do so.

This has been a recurring problem on the creek over the years, and is likely due to polluted road wash that carries contaminants into the water. There are ongoing studies in Washington State that point to a toxic brew of contaminants in stormwater as being lethal to coho, which seem particularly susceptible to it.

We found this coho male today

And this coho female full of eggs a couple of days ago

We get so few coho back to Byrne Creek that we treasure every one, and it’s so sad to see them die without completing their life cycle.

We desperately need to infiltrate water washed off from roads and parking lots into the ground through swales and rain gardens. The ground acts as a natural filter. Yet the Byrne Creek watershed in Burnaby, BC, is seeing more and more ground paved over despite hundreds of hours of professional and public input into Stormwater Management Plans and a recent Environmental Sustainability Strategy.

Note that it is illegal to interfere with spawning salmon. Streamkeepers have training and permission to process dead salmon to collect data on species, size, spawning status, etc. We return the carcasses to the creek after processing as they provide food and nutrients to other fish, animals and the overall ecosystem.

UPDATE (Dec. 7, 2017): More research coming from the US northwest.