Biological, environment, and social conflicts caused by salmon farming
By Coastal Alliance for Aquaculture Research, July, 2015
What is Salmon Farming?
Salmon aquaculture (farming) is the industrial production of salmon from egg to market in a net-cage, pond or contained system. Most of the industry still uses open net-cages in the ocean, and these floating feedlots hold up to a million fish in an area the size of two football fields.
In BC, the open net-cages are generally sited in sheltered bays along the coast in close proximity to wild salmon streams and rivers.
Salmon Farm Facts
- A salmon farm is likely to hold 500,000 to 750,000 fish in an area the size of four football fields.
- The biomass of farmed salmon at one farm site can equal 480 Indian bull elephants – that is 2,400 tonnes of eating, excreting livestock.
- Salmon are carnivores. On average it takes two to five kilograms of wild fish (used in feed) to produce one kilogram of farmed salmon.
- In one study, over a billion sea lice eggs were produced by just twelve farms in a two week period. preceding the out-migration of wild juvenile salmon.
- Infection with one to three sea lice can kill a wild juvenile pink salmon.
- In British Columbia alone there are approximately 136 salmon farm licenses with over 85 farms active at any given time.
- Canada and Chile are the two primary sources of farmed salmon for American consumers.
- Two-thirds of the salmon consumed by Americans is farm-raised.
- The government and industry would like to see BC farmed salmon production double within the next 10 years — that means twice the toll on our oceans, wild fish and coastal livelihoods.
Environmental Impacts
Currently, BC has an average of over 85 open net-cage fish farms operating at any given time in our coastal waters.
There are presently 136 licensed farm sites but some will always be empty of fish, or “fallowed.” Despite occasional fallowing, industrial open net-cage farms create huge environmental impacts that will only increase if the industry continues to expand.
Impacts
Salmon farming is one of the most harmful aquaculture production systems. The industry uses open net-cages placed directly in the ocean, where farm waste, chemicals, disease and parasites are released directly into the surrounding waters, harming other marine life. Escapes of thousands of farmed fish are common in this industry, as are the deaths of natural predators like sea lions and seals who are attracted to the pens of fish.
Raising carnivorous fish like salmon that require a high percentage of protein derived from wild fish in their feed also has a significant impact on the environment. More kilograms of wild fish are used to raise salmon than farmed salmon produced, depleting wild fish stocks rather than supplementing them.
The vast majority of salmon farming operations depend on the use of vaccines, antibiotics and pesticides to control disease and parasites that are often exacerbated by the high densities required to make industrial livestock operations profitable.
Learn more about each of these impacts by following the links below:
- One of the most devastating impacts of salmon farming is the risk sea lice pose to juvenile wild salmon. Sea lice proliferate on salmon farms and spread to surrounding waters attacking baby salmon as they head out to sea. Learn more about the weight of scientific evidence documenting the impacts of sea lice on wild salmon.
- When over half a million or more farmed salmon are penned in a small area, fish feces and waste feed can have a significant impact on the ocean bottom and surrounding ecosystems, especially in shallow waters or areas that do not flush well.
- Despite regulations and management practices intended to limit farmed salmon escapes, escapes still happen in every salmon farming region in the world, BC included. Learn more about how escaped farmed fish compete with wild salmon for habitat and food.
- Open net-cages attract natural fish-eating predators like seals and sea lions. Some of these marine mammals are shot by fish farmers that feel that the animals are a threat to their stock. Others become ensnared in the nets surrounding the open net-cages and drown. An untold number of seals, sea lions, dolphins and porpoises are killed annually by salmon farms. Learn more about marine mammal deaths.
Closed containment systems offer a promising solution to many of the problems created by open net-cage farming. Find out more about closed containment.
Sea Lice
Sea lice are small marine parasites that occur naturally on many different species of wild fish including wild adult salmon. Sea lice are planktonic and are transported on the tide. When they encounter marine fish they attach themselves, usually on the skin, fins and/or gills and feed off the mucous or skin.
There are 13 known species of sea lice in the marine waters of British Columbia, but the common ‘salmon louse’ is the one we hear the most about. The Latin name for this salmon louse is Lepeophtheirus salmonis.
Sea Lice & Salmon Farms
Sea lice from salmon farms are one of the most significant threats facing wild salmon in British Columbia. Stocked year round with hundreds of thousands of fish in small areas (net-cages) fish farms are ideal, and unnatural breeding grounds for lice. Infestations on farms significantly increase the number of lice in surrounding waters, far beyond what would occur naturally.
In the spring, when fish eggs hatch and juvenile salmon emerge from the rivers and make their way to the ocean many are exposed to sea lice during their journey because fish farms are typically located in sheltered waters along wild salmon migration routes. Juvenile pink and chum salmon are smaller than an AAA battery when they migrate by salmon farms and some may not have fully developed scales yet. When lice attach themselves to juveniles, their bodies may not be able to cope, and they may die.
Peer-reviewed research has shown that one to three sea lice are enough to kill a juvenile pink salmon newly arrived in saltwater.
To understand the link between salmon farms, sea lice and wild salmon – watch this short video:
Disease
There are four major infectious diseases that affect salmon in industrial farming operations:
- Infectious Salmon Anaemia (ISA)
- Infectious Hematopoietic Necrosis (IHN)
- Furunculosis
- Bacterial Kidney Disease
One of the most devastating diseases is Infectious Salmon Anaemia (ISA). ISA was first detected in Norway in 1984. Since then, it has spread Scotland, eastern Canada and the USA. In 2007 an outbreak among Chilean salmon farms became an epidemic leading to the death or destruction of 70% of the country’s farmed salmon. Now for the first time the ISA virus has been detected in the North Pacific. See CAAR’s statement on the discovery of ISA in BC.
Infectious Hematopoietic Necrosis (IHN) is a virus that affects both wild and farmed salmon. Sockeye, chinook, coho, rainbow trout and Atlantic salmon can all contract the virus, but Atlantic salmon are particularly susceptible. IHN is a virus and not a bacterial infection and infected fish are not treated with antibiotics.
Furunculosis is another highly infectious disease. It is caused by the bacterium Aeromonas salmonicida, Both Atlantic and Pacific salmon are susceptible to this disease at all stages of their lifecycle. It causes large boils to appear on the surface to the skin.
In 2005 furunculosis killed 1.8 million Atlantic salmon smolts at a single commercial salmon hatchery on Vancouver Island. The disease occurs in salmon farms throughout Scotland, Norway, Canada, the Broughton Archipelago in British Columbia, and Washington State.
Bacterial Kidney Disease is a chronic systemic bacterial condition of fish of the family Salmonidae caused by Renibacterium salmoninarum. Infection can result in significant mortalities in both wild and farmed salmonids. Nearly all age groups of fish can be affected, although the disease is rare in very young fish. Losses are generally chronic, occurring over an extended period. It affects fish in freshwater and seawater environments and can have a serious economic impact, particularly in seawater Atlantic salmon farms.
The first outbreak of bacterial kidney disease in farmed salmonids in Scotland was recorded in 1976. Since thn it has been found in salmon farming operations around the world.
Vaccines and antibiotics are used in salmon aquaculture to control infections. Vaccines are given by inoculation but antibiotic treatments are typically done through medicated baths and medicated feed. The latter two methods of delivery increase the chance that antibiotics will pass into the environment, affecting wildlife and other organisms, and remaining for long periods of time.
Learn more about antibiotic use in open net-cage salmon aquaculture or learn about closed containment systems, techology that may help control the spread of disease to wild stocks.
ISA and IHN are listed as reportable diseases by the World Organization for Animal Health. This means that immediate notification to the world body is required within 24 hours if an outbreak of these disease occurs in a country or zone or compartment of the country that was previously considered to be free of that particular disease.
Algae Bloom
Algae blooms are the uncontrolled growth of one or more species of algae, which may result from excessive nutrient loading in combination with adequate light, temperature, and other environmental factors.
Hundreds of thousands of salmon excreting in the confined area of a farm can cause a localized level of nutrient loading that may not be completely absorbed by the surrounding environment; hence, nutrient loading from salmon farms may be linked to algal blooms.
Similarly, climatic events and ocean currents can cause off shore pockets of nutrient rich water “well up” in near shore areas and cause similar blooms.
Algae blooms are a widespread problem for salmon farmers up and down the entire BC coast, particularly during late summer and early fall. This is when high concentrations of an algae known as Heterosigma akashiwo tends to bloom. It is transported by wind or water currents into salmon net pens and, at high enough densities can kill the fish in a short period of time.
In September 2007, Marine Harvest Canada had approximately 260 tonnes of farmed Atlantic salmon die by algae blooms at a farm in Klemtu, BC.
Closed containment systems could prevent nutrient loading in the ecosystem by recovering or treating waste. Learn more about the closed containment solution.
Marine Mammal Deaths
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| Sea lion caught in farm net. Photo: Twyla Roscovitc |
News update, February 2012: Charges laid against Grieg Seafoods for deaths of dozens of marine mammals. Details here
When consumers see a farmed salmon steak on the supermarket shelf they are likely unaware that marine mammals, such as seals, sea lions and porpoises, may have been killed as the result of the production of the farmed fish.
Open net-cages attract marine mammals who are natural predators of salmon. Whether a salmon farm obtains a license to shoot the mammals that threaten their stock or the creatures are ensnared and drowned in the nets surrounding open net-cages, as routinely takes place, the death of seals, sea lions, porpoises and birds is a cost of farmed salmon production that is hidden from the consumer.
Citizen and community reports and footage shed light on the magnitude of marine mammal deaths caused by entanglements in salmon farm predator nets.
Watch a short video from callingfromthecoast.com of a sea lion caught in an underwater net pen at Wehlis Bay.
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