Sea lice outbreaks at salmon farms in Passamaquoddy and Cobscook bays this summer have contributed, along with warm water temperatures, to the loss of thousands of fish and presented a significant challenge to the industry, but the losses have not placed the fish farming companies in financial jeopardy. While concerns have been expressed by a coalition of fishermen's associations about the impact on species such as lobsters by the pesticides used to treat sea lice, salmon farmers point to the monitoring of treatments by regulators of the industry that they show no impact on other species from the treatments. The fish farmers also note that they are moving toward using more "green" technology in trying to manage the salmon parasite.  
     Nell Halse, vice president of communications for Cooke Aquaculture, says that, since the number of fish affected is a small percentage of the company's overall production, the outbreaks "in no way put the company in jeopardy." Also, the water temperatures have now peaked, so the number of mortalities is diminishing.
     Salmon farmers say a significant part of the problem this summer was caused by not receiving approval from Health Canada for some of the chemical treatments until late June, so they could not be proactive in dealing with sea lice. Having to be reactive in managing the parasite, coupled with the high water temperatures, caused the challenges for the salmon farmers, according to Pamela Parker, executive director of the New Brunswick Salmon Growers Association.
     This summer sea lice have been a significant problem in the upper Passamaquoddy Bay area, where water temperatures have been 14 degrees C or higher, when they normally are about 12 degrees C. Sea lice are naturally occurring, and their life cycle accelerates as water temperatures increase. The high temperatures also cause plankton blooms and decreased oxygen levels in the water, which stress the fish and can place them at risk. The mortalities may be caused by a number of temperature-related issues, including the low oxygen levels and plankton blooms, along with the sea lice.

Addressing concerns about use of pesticides
     Concerns have been raised about the use of pesticides to treat sea lice, with the Traditional Fisheries Coalition recently calling on federal Minister of Fisheries Gail Shea to make a public statement regarding the eventual elimination of the use of the chemicals in the marine environment. Some of the pesticides can kill crustaceans, and that concerns fishermen, who feel that lobsters are at risk, in addition to krill and shrimp, important food sources for fish, whales and seabirds. The coalition is made up of the Fundy North Fishermen's Association, Fundy Weir Fishermen's Association, Grand Manan Fishermen's Association and Connors Brothers Ltd.
     To help manage the sea lice outbreaks this year, Parker says the fish farming industry has been evaluating the use of "green" technology, including the use of well boats for administering the bath treatments for the fish, instead of tarps around the fish cages, and the use of hydrogen peroxide, which is a more benign chemical that breaks down into hydrogen and water. The salmon growers association aims to measure the effectiveness of using the well boats both in treating for sea lice and in reducing the environmental footprint of the treatments. The use of the well boats reduces the overall amount of product used and minimizes potential effects on other species and the environment, according to information provided by the provincial Department of Agriculture and Aquaculture. "Sea lice can be effectively managed through good husbandry, a full suite of treatment tools and technology to enhance treatment efficacy," a statement released by the department says. "We are confident with the initiatives that have been taken over the last eight months that we can effectively manage sea lice as we go forward."
     Three well boats are now being used for treating the salmon. The first one, the Ronja Carrier from Norway, was chartered by the New Brunswick Salmon Growers Association and is being shared by different companies. The charter arrangement ends in December. The two largest companies have since purchased their own well boats, with Northern Harvest Sea Farms acquiring the Ronja from Norway and Cooke obtaining the Colby Perce from Chile.
     After treatments are administered in the well boats, the water is released into the bay. That water is monitored to look for any remaining therapeutant, how soon it disperses, where it goes and any impact on non-target species such as lobsters and fish. According to Parker, the provincial Department of Agriculture and Aquaculture, the federal Department of Fisheries and Oceans and Environment Canada all participate in monitoring the treatments, including tracing the path of the residue as it leaves the well boat or tarped area. Using a dye in the treatment, they are able to follow the residue until it is dispersed and also test plankton and species such as mussels and lobsters that are in the area.
     A statement from the Department of Agriculture and Aquaculture says, "All bath treatments have been subject to a rigorous risk assessment via the appropriate regulatory agencies prior to use. The risk assessment considers potential effects of the product on human and animal health and the environment. Any use of therapeutants for the purpose of managing sea lice has been subject to monitoring pre and post treatment."
     At least two of the chemicals, AlphaMax, which was licensed for use in certain areas of New Brunswick last year, and Excis, a trade name for cypermethrin, which has been permitted for specific periods of use in Cobscook Bay in Maine, are toxic at certain concentrations to crustaceans, including lobsters, and fish and plankton. During the licensing process for AlphaMax, trials were conducted using the insecticide, in which lobsters were placed in cages in the line of current from salmon cages where the chemical was administered. The lobsters were placed under observation for a year at the St. Andrews Biological Station, and all of the lobsters survived and their life cycles were not interrupted, according to Parker. Environmental monitoring of the water when cypermethrin has been used at Cobscook Bay fish farms has shown that the chemical is at non-detectable levels in the waters or in any of the nearby environment where samples have been collected.
     A national fish health working group looked at possible sea lice treatment options that are used in other countries without posing a risk to the environment. The salmon growers association then worked with the provincial government to obtain approval from Health Canada for the different products. They all have prescribed dosage and maximum annual treatments that can be completed, according to the Department of Agriculture and Aquaculture.
     In Maine, Cooke has been using hydrogen peroxide and cypermethrin, which is not permitted for use in Canada. At New Brunswick sites, Cooke has been using hydrogen peroxide bath treatments, but once the water temperatures get too high, that treatment cannot be used, since it hurts the fish. Although hydrogen peroxide hasn't been used during the past few weeks, the salmon companies hope to be able to use it again soon.
Salmosan is also being used in the well boats, with the salmon growers having just received approval for its use. Halse says that the amount that has to be used in the well boats is about a third of that which was used when the salmon were treated in tarps in the cages.
     AlphaMax was being used last year in bay management areas that are now fallow, and the salmon industry is now seeking to obtain approval for its use in all of the bay management areas. Two other therapeutants, Slice and Calicide, are in-feed treatments that are authorized for use. "We want to rotate the treatments so the sea lice don't develop resistance," notes Halse. They then would not have to readminister treatments at the same cage sites.
     Until last year, only one product, Slice, was licensed in Canada for treating sea lice, but it has not worked as effectively recently. "We didn't get approval in time" to use some of the therapeutants earlier in the year, says Halse. "We wanted to get the levels down so we could manage them, but we couldn't do aggressive treatments early." Cooke has been "struggling this summer" to manage the sea lice outbreaks. "If we had had the proper tools, this would not have happened," she says. "It reinforces the need for the salmon farming sector to have the tools to manage fish health. It's frustrating because other countries do have them."
     Parker says the industry would like to move away from using pesticides, and the use of hydrogen peroxide in well boats has been part of that process. Some countries are also using cleaner fish that eat the sea lice. Parker says the New Brunswick industry has reduced stocking densities in the cages to some of the lowest in the world, but she notes that fish densities have a limited impact on reducing sea lice numbers.
     Now that water temperatures are dropping, hydrogen peroxide can be used again, and the salmon farmers are hoping to go into the winter with fish that do not have sea lice and then use hydrogen peroxide in the spring to prevent such outbreaks next year. Halse observes, "If we can get approvals before winter and hit hard next spring, we'll be better able to manage it next year."