Dead cutthroat trout, about 76 in total, littering the banks and stream bed of West Vancouver's Larson Creek last week provided a grim reminder of how fragile the ecosystems near our towns and cities can be.

"It sounds melodramatic, but for us it's total devastation; I have no idea if there are any fish left in this creek," said John Barker, the president of the West Vancouver Streamkeepers Society.

On Monday, Barker inspected the little pool that was created to give fish a habitat in the creek, adjacent to Gleneagles golf course, but he couldn't find any trace of the fish that were there a week earlier.

"It's such a setback and so frightening," said Barker.

West Vancouver Streamkeepers president John Barker inspects Larson Creek to see if there's any trace of the trout that were killed there a week earlier. (Rafferty Baker/CBC)

Nearby highway work

The deaths are being blamed on construction work across the street, where crews are doing a ground stabilization project.

The Ministry of Transportation provided CBC News with a written statement, saying "the incident which occurred at Larson Creek as a result of construction was unexpected and unacceptable, and the ministry is working with the contractor to ensure this type of incident won't happen again."

"It is our understanding that this unfortunate incident was the result of a construction contractor performing a pressure test on some equipment using clean water and then disposing of the water within the project site," said the ministry.

"The water unexpectedly caused erosion which infiltrated the ground and caused turbid water to flow underneath the surface to a nearby culvert and then enter Larson Creek."

A construction worker walks across the site adjacent to Larson Creek where the creek contamination originated. (Rafferty Baker/CBC)

Barker said a plume of contaminated silt must have flowed down the creek, killing the fish and any other critters in its path. He was notified of the incident after golf course employees reported the dead fish to the municipality.

"By the time you get here to check it, you can take a water sample, everything looks fine ... but the damage has been done, and this is probably the case in this one. Nobody saw the plume," said Barker, who said he's not confident the fish population can recover, since it was unique to the creek and can't necessarily be re-introduced.

Other nearby cases

About two or three kilometres east of Larson Creek, the streamkeepers were investigating another sudden fish death incident that took place at Wood Creek on April 19.

In that case, about 50 cutthroat trout were killed, according to Barker, but there was no nearby construction work to blame, and Barker speculates some residential waste water got into the creek.

The B.C. Ministry of the Environment didn't get a report about that incident, but staff is investigating yet another case — this time in North Vancouver's MacKay Creek near Handsworth Secondary School, where more than a dozen juvenile coho salmon and cutthroat trout were found dead in late April.

No pollution or contamination was found in MacKay Creek.

The dozens of dead cutthroat trout in Larson Creek measured three to eight inches. According to John Barker, they all sank to the bottom of the creek. (John Barker)

Barker said in all three cases, the deaths probably weren't intentional, but the result of human carelessness in regard to sensitive fish habitat.

His message for people living, working and playing near waterways, even seemingly insignificant ones?

"Treat the creeks with respect; they're precious and they've got life in them," said Barker, adding that it could be awhile before most of that life returns to Larson Creek.

Follow Rafferty Baker on Twitter: @raffertybaker