Farmed and Dangerous Blog

What is DFO doing to protect juvenile Fraser River sockeye salmon from sea lice infestations during this migration season?

Posted by: Michelle Young | June 28th, 2011 | Comments Off

Sea lice on wild salmon

Many of the juvenile salmon now migrating through the Discovery Islands are the offspring of the Fraser River sockeye that collapsed in 2009. This subgroup of fish with a troubled past are faced with myriad hazards as they struggle for survival, but adding to their peril (and of course the peril of all wild juvenile salmon) are the rising lice levels on salmon farms.

The conditions attached to the new Fisheries and Oceans Canada (DFO) marine finfish aquaculture licenses for farms growing Atlantic salmon state that if levels reach or exceed three motile lice per fish during the out-migration period for sensitive juvenile wild salmon from March 1st to July 1st, specific actions to reduce infection must be taken within fifteen days of exceeding the threshold. Yet a graph tracking lice levels on the group of Atlantics being grown at Marine Harvest Canada’s (MHC) Chancellor Channel Farm shows that the three lice per fish threshold was reached near the end of May, with levels trending upwards to four lice per fish into June. Lice levels at the company’s Lees Bay farm had passed the treatment threshold as of May 11th.

Both of these farms are located near Johnstone Strait on the Fraser sockeye migration route. Marine Harvest deserves credit for web-posting fairly up-to-date and detailed information on the number of fish in their farms, lice levels per fish and treatment dates. But it is alarming to see the lice levels climbing during the wild juvenile sockeye out-migration.

MHC has now informed CAAR that the Chancellor and Lee’s farms are receiving pesticide treatments. But how high will the lice levels have climbed before the treated feed was milled, shipped to the site, fed to the fish and began to take effect to lower lice levels? There are approximately 430,000 farmed fish in the Chancellor pens. Four lice per fish add up to about 1,720,000 lice on the farm. And that number can rise rapidly in the period between identifying the need for treatment and treatment results.

Meanwhile, how far will the lice travel and what affect will they have on the out-migrating sockeye running the gauntlet? Modeling research in BC suggests that a single salmon farm can increase naturally occurring sea lice levels by 73 times and elevate infection rates for 30km beyond the net-cages.

It’s also worth noting that this farm had over three lice per fish at the end of August 2010 until the middle of November 2010 – reaching a level of 11 lice per fish in October 2010. Overall, the farm has been in violation of the three lice per fish threshold for almost 30% of the time this group of fish has been in the water.

Clearly, DFO is failing to use their new regulatory authority to properly control the industry in order to stop the proliferation of sea lice on salmon farms. While a federal inquiry is underway to determine why the 2009 Fraser sockeye run collapsed, and the impacts of open net-cage salmon farms are among the factors being investigated, it seems little is being done to protect the progeny of that run of wild sockeye.

Wild salmon migration routes will never be safe for juvenile salmon as long as net-cage farms are in the water. The only way forward is for DFO to modernize its approach to salmon aquaculture and initiate the transition of the industry to closed containment technology.

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