North Island coho runs were decimated by DDT experiment

Brenda McCorquodale's history column looks at 1950s DDT use on the North Island.

We don’t have to look very far into our history to see some surprising examples of what once constituted ‘acceptable environmental impacts.’

In 1955, North Island foresters realized they had a problem. The valuable stands of timber in the area from the Nimpkish River north were seeing a significant infestation of the black-headed budworm. Worried about the possible impact on timber supplies, the province decided to experiment with a new treatment that was first used to kill parasites during World War II to prevent the spread of malaria and typhus.

Dichlorodiphenyltrichloroethane, known more commonly as DDT, is colourless, tasteless, and almost odourless.

The government knew that the DDT application could have significant effects on the local fish and wildlife, and involved the Department of Fisheries and the Game Commission in the experiment. Flight patterns were designed to avoid rivers.

The treatment on North Island forests involved mixing one pound of DDT with a wood penetrating emulsifier, added to a gallon of diesel oil.  One gallon was then applied per acre by low-flying aircraft, with a total of 155,000 acres being sprayed in effected areas between June 10 and 20, 1957.

The spraying annihilated almost all insects within the treatment area.  Even stream-dwelling insects were almost totally eliminated, as recorded at number of stations sampled prior to, immediately after, and four months following the application.

The impacts on salmon were also catastrophic.  It was hoped that the timing of the application would minimize impacts on local salmon runs, but there were many tens of thousands of juvenile coho salmon and trout within local watersheds at the time.

Thousands of chum fry died as a result of the DDT application in the estuary of the Nimpkish River.  In the Keogh, Waukwass, Klaskish, and Benson Rivers, coho salmon mortality approached 100%. Steelhead trout may also have suffered significant losses. There were also lesser impacts on other North Island streams and rivers.

Researchers concluded that the decimated runs would take many years to rebuild. There were suggestions that juvenile fish from other areas could be flown in to Port Hardy to restock local creeks. Some reports of the day noted that it was good the area was isolated, because it would mean light angling pressure in the affected creeks.

Rachel Carson used the North Island DDT application as an example of the the harmful environmental impacts of synthetic pesticide application in her famous book Silent Spring (1962).

Some local people from Quatsino Sound have reported that the Marble River watershed had a rain event shortly after the DDT application, and that there were piles of dead sea creatures which washed up on the shores of Quatsino Sound in the following days (I would be interested in any further information for our collective historical record).

Brenda McCorquodale is a Port Hardy resident and North Island history enthusiast. If you have any stories or local lore you’d like to share, email her at storeysbeach@gmail.com. A collection of her past articles is available on her blog at http://undiscoveredcoast.blogspot.ca/.

 

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Emma Garriott is releasing her second album titled ‘Sad White Girl Angst.’ (Emma Garriott / Facebook photo)
North Island musician releases second album titled ‘Sad White Girl Angst’

“When you hear it, I want you to feel like your best friend in the whole world is sitting beside you’

Environment Canada has issued a special weather statement forecasting windy weather Sunday and Monday. (News Bulletin file photo)
More windy weather on the way for Vancouver Island

Environment Canada issues special weather statement for Victoria, east coast of Island, north Island

Jay Vaughn, Brian Pohto and Janet Pohto opened up the Island Sun’s tuna freezers for anyone worried about food thawing over the four-day power outage on Malcolm Island. (Christopher Hurst photo)
Community shines bright during power outage

Hardest hit areas on the North Island stepped up to keep neighbours warm and fed

Mary Cox and Jack Plant dance in their pyjamas and slippers at the morning pyjama dance during the Rhythm Reelers’ 25 Annual Rally in the Valley Square Dance Festival in Chilliwack on June 4, 2011. Sunday, Nov. 29, 2020 is Square Dancing Day. (Jenna Hauck/ Chilliwack Progress file)
Unofficial holidays: Here’s what people are celebrating for the week of Nov. 29 to Dec. 5

Square Dancing Day, Disability Day and International Ninja Day are all coming up this week

Black Press Media and BraveFace have come together to support children facing life-threatening conditions. Net proceeds from these washable, reusable, three-layer masks go to Make-A-Wish Foundation BC & Yukon.
Put on a BraveFace: Help make children’s wishes come true

Black Press Media, BraveFace host mask fundraiser for Make-A-Wish Foundation

Kevin Bieksa during his days playing with the Vancouver Canucks. (Photo: commons.wikimedia.org)
Bieksa to guest on free Canucks Alumni ‘Hot Stove’ on Zoom app

Former NHL player has become a game analyst on Sportsnet

A small crash in the water south of Courtenay Saturday afternoon. Two men had to be rescued, but reports indicate there were no serious injuries. Photo by Mike Chouinard
Small plane crash in Comox Valley waters Saturday afternoon

Two rescued from plane that had flipped in water; no serious injuries reported

A photo from 2017, of Nuchatlaht First Nation members outside court after filing a land title case in B.C. ( Submitted photo/Nuchatlaht First Nation).
Vancouver Island First Nation calls on B.C. to honour UNDRIP in historic title case

Nuchatlaht First Nation says Crown counsel continues to stall the case using the ‘distasteful’ argument that the Nation ‘abandoned’ their land

West Vancouver Island’s Ehattesaht First Nation continues lock down after 9 active cases were reported today after a visitor tested positive last week. (Ehattesaht First Nation/Facebook)
Ehattesaht First Nation’s COVID-19 nightmare: nine active cases, a storm and a power outage

The Vancouver Island First Nation in a lockdown since the first case was reported last week

114 Canadians were appointed Nov. 27 to the Order of Canada. (Governor General of Canada photo)
Indigenous actor, author, elder, leaders appointed to Order of Canada

Outstanding achievement, community dedication and service recognized

The Ahousaht First Nation confirmed its first case of COVID-19 on Nov. 26, 2020. (Westerly file photo)
Ahousaht First Nation on lockdown over COVID-19

“Emotions are high. The anxiety is high. We want our community to pull through.”

Most Read