The salmon farming industry in New Brunswick is always on the lookout to
improve both the environmental management of their operations and improve the health management protocols that will ensure a healthy farm stock that result in a wholesome product for our customers.
Articles have been written-including a recent one in this publication (“New Brunswick sea lice treatment generates opposition,” Working Waterfront, August issue) -regarding the trials to test a new option for fish health management on our farms.
That treatment recently questioned is AlphaMax, the brand name for
deltamethrin, which is approved for trials off parts of the New Brunswick
coast. Those trials are being carried out by salmon farmers under strict
conditions-including who can administer it, how much can be used and even how much can be brought to a salmon farm. With researchers from the New Brunswick Department of Agriculture and Aquaculture overseeing the collection of data, the effects of the treatment are becoming clear-a low concentration of deltamethrin is killing more than 90 per cent of sea lice and researchers can find no trace of the chemical in the bay once the treatment is complete.
AlphaMax trials ran on select salmon cage sites starting July 9 and will end
in late August. Extensive monitoring is part of the experimental treatment
and so far the results are promising. According to Dr. Michael Beattie, a
veterinarian with the provincial aquaculture department, AlphaMax is killing sea lice without impacting the surrounding environment.
AlphaMax is administered to salmon in cages surrounded by protective skirting that falls to a depth of seven metres and effectively keeps the AlphaMax confined to the cage itself during the 40-minute bath. That
skirting is so effective, in fact, that during an application on August 12 in Lime Kiln Bay, oxygen levels in the cage dropped, forcing crews to add oxygen during the bath.
Researchers have taken water samples in the cage, around the cage and
downstream from the cages to ensure they are getting a thorough and accurate picture of where the AlphaMax is going during and after treatments. They also used plankton tows. Within 10 minutes after treatment, the AlphaMax is undetectable.
A system of testing the impact of AlphaMax on sentinel species-such as
lobster, crabs, mussels and sea cucumbers was also established. To date
there has been no ill effect to any of the organisms. Scientists will continue to monitor those lobsters in labs at the St. Andrews Biological
Station to ensure there are no long-term impacts. The lobsters that are used
in the experiment are at various development stages and include larval
lobster, adults and egg-bearing females.
These trials have generated some criticism and concern from environmental
groups and the traditional fisheries. Those groups have a right to be
concerned, to ask questions. The water is theirs too. The bay is a shared
resource. The salmon farming industry is answering those questions head on, including at a meeting with stakeholders on August 13 in St. George, New Brunswick. Beattie said this research has one basic, simple goal-if it is found that deltamethrin treatments pose any threat or do any harm to any non-target species, the project be shut down.
The trials are part of the salmon farming industry’s effort to expand its health management strategies and tools-a diversification strategy supported by salmon conservation organizations like NASCO. Since 2002 the amount of therapeutants used to treat sea lice on New Brunswick salmon farms is down 50 per cent. Diversifying the treatments available-adding AlphaMax to the existing treatment, SLICE (the only treatment currently approved in Canada)-may help reduce overall use even more. Alternating a variety of treatment options helps to ensure optimal benefit from each over time. So it’s essential the industry have access to a broad range of tools to optimize the disease prevention and parasite control. The salmon farming industry also uses natural control measures like reducing stock density, fallowing and temperature; however, therapeutants are also necessary at times.
Salmon farmers have a genuine concern about the environment. A broad
diversity of natural species is evidence of a healthy marine environment and
its important that it is maintained-not just because it’s the best environment for growing healthy fish but also because it supports a diversified working waterfront and benefits our neighbors too.
Pamela Parker is the executive director of the New Brunswick Salmon Growers Association.