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FrançaisLousy Choices II: Pricey De-lousing Equipment gets Failing Grades
Pricey De-lousing Equipment gets Failing Grades
VANCOUVER: Expensive new vessels are failing to control the parasites that are decimating wild salmon stocks, according to a report released today by Living Oceans Society. The report analyses the treatments given on the farms over the past two years and assigns a failing grade to the Hydrolicers and wellboats purchased by salmon farming companies at reported costs of $12 to $30 million.
The costly de-lousing equipment was touted by salmon farming companies as the answer to lice control now that the lice are developing resistance to SLICE ™, the in-feed drug they’ve been using since the early 2000’s. Living Oceans’ report analyses the data reported by the salmon farmers themselves and concludes the treatments are failing:
- 70 percent of treatments failed to reduce lice numbers for more than 4 weeks;
- 85 percent of treatments failed during spring outmigration, resulting in devastating lice loads on outmigrating salmon, especially in Nootka Sound and the Discovery Islands;
- once the lice count reaches 3 per farmed fish (the current limit set for treatment to begin), treatment efficacy declined sharply:
- freshwater baths were effective about 1/3 of the time;
- hydrogen peroxide baths were not effective at all;
- Hydrolicer treatment scored 12.5-25% effective.
“They simply can’t keep up with the lice,” said report author Karen Wristen. “This year, nearly 38 percent of operating farms saw lice counts go up over the 3-lice limit during the spring, while wild salmon smolts were migrating by the farms. That’s sharply increased over the past two years, that saw 21-25 percent of farms over the limit—and there were 20 percent fewer farms operating this spring.”
“The only times this equipment proved really effective were when treatment was started while the lice count was still really low—below 1 louse per fish,” said Wristen. “It was also more likely to be effective if the farm being treated was isolated from other operating farms, or all farms in the area were maintained at similarly low lice levels.”
The report makes seven recommendations for immediate implementation by the Department of Fisheries and Oceans, to prevent another season of wild salmon smolts being decimated by salmon lice. Read the full text here: Lousy Choices II: The Failure of Sea Lice Treatment in British Columbia, 2019-2020.
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Contact Information
Karen Wristen, Executive Director 604-788-5634
Background
Wild Salmon Impacts, 2020
Sockeye, pink and chum salmon sampled in 2020 were infected at the following rates, according to figures released by independent monitors at the Salmon Coast and Cedar Coast Field Stations:
Broughton 34%, Clayoquot 72%, Nootka 87% and Discovery Islands 94%
Infected fish carried an average lice number of:
Broughton 1.3 Clayoquot 3.1 Nootka 8.9 and Discovery Islands 7
Average numbers, however, are poor indicators of the fate of infected fish as they generally include data from sites near natal rivers, as well as sites more proximate to salmon farms. For example, at the three Nootka sites near salmon farms 99% of juvenile wild salmon were infected with an average of 9.3 sea lice per fish. Nevertheless, even the average numbers of lice reported here are sufficient to kill juvenile pink and chum salmon (the majority of the samples). Discovery Island sockeye samples were also infested at a rate (99%, average lice count that calls into question the survival of this year’s Fraser sockeye smolts.
Broughton results are the best in memory and are attributed to the closure of several farms along the outmigration route, pursuant to the landmark Broughton Agreement that has ‘Namgis, Kwikwasut’inuxw Haxwa’mis and Mamalilikulla First Nations co-managing salmon farming.
The De-Lousing Equipment
In 2019, the three companies farming Atlantic salmon in B.C. all announced the arrival of new equipment to treat farmed salmon for sea lice.
MOWI Canada West’s Aqua Tromoy was described as a $30-million, state-of-the-art wellboat that could provide freshwater and medicinal bath treatments. Grieg Seafood BC Ltd. put a price tag of $50 million on its similar wellboat; and Cermaq Canada announced it had purchased a Hydrolicer for $12 million USD, that would use ocean water under pressure to dislodge lice from its fish. MOWI was already operating a hydrolicing barge here on the coast, cost unknown.
While the numbers are big (and so are the boats), this represents precious little equipment to deal with 60-70 operating farms located from Sechelt to Klemtu, including both coasts of Vancouver Island. The vessels take several days to process all the fish at one farm and must then leave the immediate area to discharge the waste treatment water (and, unfortunately, the lice they just removed from the fish) and refill the wells for the next treatment.