First Nations in B.C.’s Fraser Valley say a large spill in the historic Hope Slough waterway on Monday has led to the death of thousands of salmon and other fish.

The Cheam First Nation said in a Tuesday statement that the spill was discovered on Monday when community members went out to the waterway to check on years-long restoration efforts led by the Cheam and Sqwá First Nations.

The nations say thousands of fish — including juvenile coho salmon, trout and the endangered Salish sucker — were killed.

The nations say the exact source of the spill has not yet been determined. The spill could mean that spawning coho stocks could be wiped out for a year, they say.

Eddie (T’ít’elem Spath) Gardner is a Sqwá First Nation councillor who is responsible for the lands and resources portfolio. He mourned the loss of the juvenile coho salmon in the Hope Slough stream. (Camille Vernet/Radio-Canada)

“I almost broke out in tears because I could see dead coho … the little ones that were all lined up along the bank here,” said Eddie Gardner, a Sqwá First Nation councillor who was one of the first to discover the spill.

“It’s very sad for us because we consider ourselves as salmon people. We consider them as our relatives.

“To see a coho kill, you know, in the stream where we’ve been making every effort to make this a good and healthy place for the salmon … is very, very disturbing.”

Dead juvenile fish were visible on the grass surrounding the Hope Slough after the spill, whose cause has yet to be determined. (Camille Vernet/Radio-Canada)

The Hope Slough, which has been given the traditional name of Sqwa:la by local First Nations, flows into the Fraser River.

Gardner says the First Nations have been trying for many years to restore salmon stocks and clean the waterway as they have been part of the nations’ cultures for centuries.

“We need to pull out all the stops, you know, to make sure that our salmon relatives don’t go … the way of the buffalo, so they don’t go extinct,” he said of restoration efforts.

‘Heartbreaking’

Roxanna Kooistra, who works for Cheam First Nation as an environmental stewardship manager, thinks the spill resulted from some kind of organic matter that flowed from upstream.

In its statement, the Cheam First Nation says the spill may be related to agriculture and farming activities upstream, with Kooistra saying the nation had deployed drones and people on foot to locate the source of the spill.

Roxanna Kooistra, who works for Cheam First Nation as an environmental stewardship manager, says she was in tears when she discovered the spill on Monday. (Camille Vernet/Radio-Canada)

“We’ve tested approximately 10 kilometres down the slough, and as far as we know all salmonids are dead as far as 10 kilometres downstream,” she told CBC News.

“There’s people fishing, there’s likely children playing in the area, and this water is now toxic for them,” she added. “We need to get the word out as soon as possible.”

An oil sheen was visible on the Hope Slough on Tuesday. The waterway feeds into the Fraser River. (Camille Vernet/Radio-Canada)

Kooistra said the nations have been working to educate the community that the Hope Slough is a salmon-bearing waterway, and it has been difficult to break through people’s preconceived notions that it is not an active stream.

“To come here and know that potentially tens of thousands of litres of toxins were released just because someone didn’t feel like paying to dispose it, it’s heartbreaking, it’s crushing, it’s disheartening for the community,” she said.

A spokesperson for the province’s Ministry of Environment said ministry staff were on site Tuesday monitoring the oil spill.

“An Environmental Response Contractor has been retained to begin mitigation and cleanup actions,” they wrote in a statement.

A boom was in place to contain the spill on the Hope Slough near Chilliwack, B.C., on Tuesday. (Camille Vernet/Radio-Canada)