The Department of Fisheries and Oceans is imposing a salmon fishing ban on the Fraser River beginning Thursday night.

Fishing for any salmon species is being suspended between the Alexandra Bridge south of Boston Bar to the Mission Bridge connecting Abbotsford to Mission.

The DFO said it has resorted to the ban in an attempt to conserve this year’s low salmon population, which was originally forecast at 4.7 million but now appears to be roughly half that.

Record-high water temperatures in the Fraser, which diminish the salmons’ ability to swim and contribute to disease outbreaks, are blamed in part for the dismal numbers.

All commercial and recreational fisheries along the Skeena River have already been closed due to a historic low sockeye return.

Just 453,000 sockeye are expected to swim the Skeena this year, compared to roughly 2.4 million last year, making for one of the worst runs in 50 years on the river.

This year’s run consists of offspring from the 2009 sockeye collapse, where just 1.5 million of the salmon showed up on the Fraser despite early predictions for 10 million.

B.C. enjoyed a banner year in 2010, however, with roughly 35 million sockeye on the Fraser alone.

News of this year’s ban came as environmentalists began sounding the alarm about alleged improper fishing practice’s along B.C.’s coasts that may have unnecessarily killed thousands of salmon.

The Watershed Watch group said boats targeting pink salmon in northern fisheries are inadvertently catching more than 165,000 salmon of other species, and sometimes letting them die before throwing them back into the water.

The group has posted video online that it claims is proof of the practice. The DFO said the footage is problematic, and warrants further investigation.

With files from The Canadian Press