Editor's note: This story has now been updated to include comments from the City of Delta.
The Cougar Creek Streamkeepers is once again raising alarm following a recent fish kill.
A disappointed Deborah Jones with the volunteer stewardship group notified the public Tuesday of the apparent fish kill caused by an unidentified substance entering lower Cougar Creek from the Westview Drive storm sewer outfall, likely occurring last Tuesday, June 11.
The group notes an estimated 300 salmonoids, including coho salmon fry and cutthroat salmon trout smolts, were killed.
Despite an investigation, the specific spill source and toxin could not be determined, she said.
“Fortunately, there are still thousands of tiny coho fry in the creek, and no doubt many beautiful 10-cm cutthroat trout smolts. Those who were upstream of the spill, and others far enough downstream, were not impacted, but unless, and until we get all street runoff filtering through landscaping before entering the creek, our precious North Delta salmon runs remain highly vulnerable to human carelessness,” Jones said.
“As one fish expert said, it's a miracle and a testament to salmon resilience, that they manage to survive at all in the toxic soup that pours off our pavements and roofs even in the best of circumstances. “
However, according to the City of Delta, staff took water quality readings upstream and downstream of the outfall which did not detect anything out of the ordinary and the water appeared to be clear.
Staff also opened the manhole at the outfall and tested the water with a chlorine strip but the test was negative.
A spokesperson with the city also noted the person who reported the incident to the also didn’t see any discolouration of the water at the time, and there was no evident cause of the fish mortality incident and live fish have recolonized the area, including at the mouth of the outfall.
The incident was reported to the province and also communicated with Department of Fisheries & Oceans (DFO).
The Cougar Creek Streamkeepers are reminding the public that all storm drains empty directly into the local salmon streams without filtration or treatment.
Examples of toxins include any harsh cleaning agent used outdoors, pool or hot tub chemicals, chemicals for cleaning concrete and driveway sealants.
The City of Delta, on its website notes, the community’s creeks, ravines and park reserves face many ecological threats including illegal dumping, invasive species, water pollution, erratic flows, erosion and climate change.
The creeks have year-round salmon rearing and spawning habitat. The main migratory salmon species in the creeks are coho and chum salmon. Non-migratory salmonids include rainbow trout and cutthroat trout.
“Storm drains collect rainwater from buildings, sumps, roads and parking lots into underground pipes that then discharge the water to local creeks and ditches, untreated. This water is called stormwater. Stormwater will pick up contaminants and debris as it moves. Examples of contaminants and debris include oils, soap, brake dust, animal or human waste, sediment and fertilizers. Because stormwater is untreated, make sure ‘only rain goes into a storm drain’ and be mindful of any chemicals used outdoors,” the city explains on its website.
The Streamkeepers said with the assistance of the DFO, they and many elementary school student helpers release 150,000 chum fry and 1,000 coho smolts into Cougar Creek every year in April.
