Sea Lice AND Salmon - Farmed And Dangerous
Sea Lice AND Salmon - Farmed And Dangerous Sea Lice AND Salmon - Farmed And Dangerous
There is noknown ‘silverbullet’ forpermanentlystopping sea liceinfestations onfish farms.Treatment1. HOW DO SALMON FARMERS TREATFARMED SALMON FOR SEA LICE?In order to avoid costly losses, salmon farmershave developed a variety of methods to preventand treat sea lice outbreaks. Good farmmaintenance and husbandry can help preventoutbreaks, and chemicals and drugs can helptreat salmon after an outbreak occurs. There isno known ‘silver bullet’ for permanently stoppingsea lice infestations on fish farms. Mostsalmon farmers use a combination of treatments,depending on the severity of the infestationand the stage in the sea louse developmentcycle. [78]Various measures can be used either beforea sea lice outbreak, or as part of a continuousmanagement regime. They include thefollowing: [79]■ Proper site location —which maximizesthe chances that farmed salmon will behealthy by ensuring that farms are notlocated near potential sources of infection,such as salmon-bearing streams and othersalmon farms;■ Adequate tidal current —which minimizesdangers associated with accumulationof sea-lice larvae;■ Separating year classes —whichprevents smolts (i.e. the lice-free, freshwaterjuveniles) from contacting the older andalready lice-infested farm fish;■ Fallowing —which breaks the reproductivecycle of sea lice, thereby reducing the riskof outbreaks;■ Minimizing crowding —which decreaseshost density and stress, and therebyreduces infection rates;■ Good husbandry —which contributes tothe health of fish. Cleaning and caring ofnets is one example;■ Cleaner fish (wrasse) —which eatparasites carried by other fish, and feed onalgae and sessile animals, such as mussels(common on nets) are a less-expensive andnon-chemical means of controlling sea licecurrently being used on some Europeansalmon farms. [64] Unfortunately, there areno native wrasse in BC. Nor is it advisableto introduce non-native species into anyenvironment—including introducing Atlanticsalmon to the Pacific coast;■ Reactive treatments —which are usuallya chemotherapeutant given to farm fisheither in food or as a bath, after a sea-liceinfestation has occurred. Bath treatments aredifficult to administer and are not effectiveagainst all life stages of sea lice. Feed treatmentsare more effective, and farmers cantreat many cages quickly. Although dilutedby surrounding water, the chemicals usedmay affect non-target wild crustaceans andmay remain in the environment from tendays to six months. [78, 80-89] The ability ofsea lice to quickly develop resistances tochemical treatments is also a major issue.[111]2. WHAT IS FALLOWING?Just like farms on dry land, fish farms can befallowed. By taking all of the farmed salmonout of a farm and leaving it empty for oneproduction cycle (two years), the seabed mayrecover from damage caused by the farmabove it. It also breaks the cycle of sea liceand other disease infestation in that farm. Fallowingis most effective if all the farms in anentire bay or fjord are emptied, because it ismuch less likely that farms will be reinfectedby their neighbours. To be effective, fallowingmust be done in conjunction with a separationof year classes to ensure that smolts are notinfected by adult fish in the same farm.3. WHAT IS SLICE?SLICE is the commercial name for emamectinbenzoate, a chemical used to kill sea lice. Ithas mostly replaced its more costly and lesseffective predecessor, Ivermectin. [41] AlthoughSLICE is currently undergoing clinical trials inNorway, Scotland, and Chile, [78] in Canada, in16 Sea Lice and Salmon: Elevating the Dialogue
2004, it has yet to be tested for food safety bythe Canadian Food Inspection Agency, [90] tobe licensed by the Bureau of Veterinary Drugs(Health Canada), or to be permitted for usethrough the Pesticide Control Act. So how is itthat salmon farmers in BC are able to useSLICE to control sea lice? They gained the goaheadthrough the Emergency Drug ReleaseProgram (EDR) which approves the use of nonapproveddrugs when recommended by veterinariansfor emergency situations. [91]Emamectin benzoate belongs to a class ofchemicals called avermectins, which areproduced by the actinomycete Streptomycesavermictilis. [92] Avermectins are axonic poisonswhich affect nerve cells causing hyperexcitednessleading to loss of nerve control. [82]Farm fish ingest SLICE as a coating on commercialfood pellets. Digestion releases thedrug to pass through the lining of the fish’sgut and into the fish’s tissues, from where ittakes about a week to be eliminated. [93]Although SLICE contains emamectin benzoate(0.2%), an active ingredient in pesticides, it isclassified as a drug because it is fed to the fishrather than applied externally. Drugs are regulatedby the Food and Drugs Act, whereas pesticidesare regulated by the Pest Control ProductsAct. [112] Whether emamectin benzoate isconsidered to be a drug or a pesticide, however,it is the same chemical. Because of its abilityto accumulate in sediments, SLICE couldbecome toxic to marine life. In fact, the labelof the pesticide ‘Proclaim’, in which emamectinbenzoate is the only active ingredient, clearlywarns that “This pesticide is toxic to fish,birds, mammals, and aquatic invertebrates. Donot apply directly to water, or to areas wheresurface water is present, or to intertidal areasbelow the mean high water mark. Do not contaminatewater when cleaning equipment ordisposing of equipment wash water.” [94]Though SLICE effectively controls all life stagesof sea lice, [95] and appears to have no negativeeffects on farmed salmon, it is not knownhow long SLICE might remain effective beforesea lice develop a resistance to the treatment.4. DOES SLICE AFFECT ANYOTHER MARINE ANIMALS?Whether or not SLICE affects animals otherthan sea lice is the cause of much argument.Industry [93] and government agencies [91]claim that SLICE is quite safe, but recent sciencewarns that SLICE may harm non-targetanimals. SLICE has been found to induce prematuremolting in lobsters (a crustacean), andto have caused female lobsters to lose theireggs prematurely. [96] Scientists in Scotlandhave shown that mysid shrimp are highly sensitiveto emamectin benzoate; [97] the equivalentof half a drop in an Olympic-sized swimmingpool is enough to poison these smallplanktonic animals. Because of its low solubilityin water, SLICE is very likely to bioaccumulatein marine sediments, [98] possibly to levelstoxic to nearby marine animals.5. WHO WINS AND WHO LOSESBY GOVERNMENT IMPATIENCE?Because SLICE is classified as a drug, and hasnot been approved through the provincial PesticideControl Act, the government can delay thefiling and/or enforcing of management plans.Fish farms get a reprieve. The public loses anopportunity to appeal government decisionsthrough the Environmental Appeal Board. Thepublic also loses a guarantee that it will evenbe informed when SLICE is being used. Fishfarmers gain the opportunity to avoid advertisingtheir intention to use SLICE until governmentadopts the permitting procedure. [114]6. HOW DOES GOVERNMENTREGULATE SEA-LICE TREATMENTS?There are, as yet, no rules governing how BCfish farmers treat lice. In Europe, protocols areprecise, even to identifying the number of sealice allowed per fish before sea-lice treatmentbecomes obligatory. In Norway, the thresholdis an average of 0.5 gravid (pregnant) femalelice/fish, [17] but even this seemingly low numbermay be excessive. [59] In BC, the usualpractice is for fish farmers to call a veterinarianwhen they become concerned about sealicenumbers. The veterinarianThere are,as yet, no rulesgoverning howBC fish farmerstreat lice.Sea Lice and Salmon: Elevating the Dialogue17
- Page 1 and 2: Sea Lice AND SalmonW WatershedatchS
- Page 3 and 4: British Columbia boasts one of theg
- Page 5 and 6: 3. CHRONOLOGY OF SALMON FARMING IN
- Page 7 and 8: 6. WHAT SPECIES OF SALMONARE FARMED
- Page 9 and 10: diseases and parasites can and will
- Page 11 and 12: ■ The health of the fish. The wea
- Page 13 and 14: Sea Lice &Salmon Farming1. WHY ARE
- Page 15 and 16: salmon farms carried an average of
- Page 17: 5. THROUGH WHAT PARTS OF THEBROUGHT
- Page 21 and 22: The government’s pink salmon corr
- Page 23 and 24: People1. WHAT IS CAAR?CAAR is the C
- Page 25 and 26: Why conserve the diversity of wild
- Page 27 and 28: 66. Tully, O. and K.F. Whelan, Prod
2004, it has yet to be tested for food safety bythe Canadian Food Inspection Agency, [90] tobe licensed by the Bureau of Veterinary Drugs(Health Canada), or to be permitted for usethrough the Pesticide Control Act. So how is itthat salmon farmers in BC are able to useSLICE to control sea lice? They gained the goaheadthrough the Emergency Drug ReleaseProgram (EDR) which approves the use of nonapproveddrugs when recommended by veterinariansfor emergency situations. [91]Emamectin benzoate belongs to a class ofchemicals called avermectins, which areproduced by the actinomycete Streptomycesavermictilis. [92] Avermectins are axonic poisonswhich affect nerve cells causing hyperexcitednessleading to loss of nerve control. [82]Farm fish ingest SLICE as a coating on commercialfood pellets. Digestion releases thedrug to pass through the lining of the fish’sgut and into the fish’s tissues, from where ittakes about a week to be eliminated. [93]Although SLICE contains emamectin benzoate(0.2%), an active ingredient in pesticides, it isclassified as a drug because it is fed to the fishrather than applied externally. Drugs are regulatedby the Food and Drugs Act, whereas pesticidesare regulated by the Pest Control ProductsAct. [112] Whether emamectin benzoate isconsidered to be a drug or a pesticide, however,it is the same chemical. Because of its abilityto accumulate in sediments, SLICE couldbecome toxic to marine life. In fact, the labelof the pesticide ‘Proclaim’, in which emamectinbenzoate is the only active ingredient, clearlywarns that “This pesticide is toxic to fish,birds, mammals, and aquatic invertebrates. Donot apply directly to water, or to areas wheresurface water is present, or to intertidal areasbelow the mean high water mark. Do not contaminatewater when cleaning equipment ordisposing of equipment wash water.” [94]Though SLICE effectively controls all life stagesof sea lice, [95] and appears to have no negativeeffects on farmed salmon, it is not knownhow long SLICE might remain effective beforesea lice develop a resistance to the treatment.4. DOES SLICE AFFECT ANYOTHER MARINE ANIMALS?Whether or not SLICE affects animals otherthan sea lice is the cause of much argument.Industry [93] and government agencies [91]claim that SLICE is quite safe, but recent sciencewarns that SLICE may harm non-targetanimals. SLICE has been found to induce prematuremolting in lobsters (a crustacean), andto have caused female lobsters to lose theireggs prematurely. [96] Scientists in Scotlandhave shown that mysid shrimp are highly sensitiveto emamectin benzoate; [97] the equivalentof half a drop in an Olympic-sized swimmingpool is enough to poison these smallplanktonic animals. Because of its low solubilityin water, SLICE is very likely to bioaccumulatein marine sediments, [98] possibly to levelstoxic to nearby marine animals.5. WHO WINS <strong>AND</strong> WHO LOSESBY GOVERNMENT IMPATIENCE?Because SLICE is classified as a drug, and hasnot been approved through the provincial PesticideControl Act, the government can delay thefiling and/or enforcing of management plans.Fish farms get a reprieve. The public loses anopportunity to appeal government decisionsthrough the Environmental Appeal Board. Thepublic also loses a guarantee that it will evenbe informed when SLICE is being used. Fishfarmers gain the opportunity to avoid advertisingtheir intention to use SLICE until governmentadopts the permitting procedure. [114]6. HOW DOES GOVERNMENTREGULATE SEA-LICE TREATMENTS?There are, as yet, no rules governing how BCfish farmers treat lice. In Europe, protocols areprecise, even to identifying the number of sealice allowed per fish before sea-lice treatmentbecomes obligatory. In Norway, the thresholdis an average of 0.5 gravid (pregnant) femalelice/fish, [17] but even this seemingly low numbermay be excessive. [59] In BC, the usualpractice is for fish farmers to call a veterinarianwhen they become concerned about sealicenumbers. The veterinarianThere are,as yet, no rulesgoverning howBC fish farmerstreat lice.<strong>Sea</strong> <strong>Lice</strong> and <strong>Salmon</strong>: Elevating the Dialogue17
Change language