Droughts in northern B.C. could threaten fish stocks

Kate Allen
August 11, 2010
The Globe and Mail

British Columbia’s dry summer is creating alarmingly low river levels throughout the province, a problem that could endanger fish populations in some regions, the provincial government warned Tuesday.

The Ministry of Environment is encouraging British Columbians to conserve water and create drought-management plans to mitigate the record low water levels in streams across B.C.

According to its website, the Peace, Liard and Skeena regions have been classified as Drought Level 3, which would indicate “concern for fish and water supplies, unless significant rainfall occurs.” Some areas in those regions only received a quarter of the amount of rainfall expected for this time of year.

The Lower Mainland also received only two-thirds of its usual rainfall. This could put salmon at risk, according to Diana Allen, a professor of earth sciences at Simon Fraser University. “The whole province is really suffering quite significantly from this dry spell,” Dr. Allen said.

In late summer, rivers in the province go through “low flow” periods after the snow pack has completely melted and glacier water stops running. Salmon spawn during this period.

Dry periods could affect salmon spawning in two ways: by creating water levels that are too low for fish to swim in, or by heating waters up, which deteriorates fish habitat.

“It’s the heat that is actually more critical sometimes than the low flows,” Dr. Allen said. Salmon are a greater concern than other species of fish. “I don’ t want to say they’re picky, but it’s a very narrow range they’re comfortable in,” she said.

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Read related stories:

• The Vancouver Sun and Times Colonist; August 11, 2010; Droughts in northern B.C. could threaten fish stocks"