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An rud bhios na do bhroin, cha bhi e na do thiomhnadh
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The Problems with Salmon Farms

Salmon farms have been linked with a range of serious, even devastating, impacts on the marine environment. Below, Bruce Sandison answers the key questions about the impacts of salmon farms. Alternatively:


Salmon farms: The Key Questions

Salmon Farm Protest Group Chairman Bruce Sandison answers key questions about the impact of salmon farming on Scotlandís environment and wild fish populations.


Are farmed salmon the same as wild salmon?
What are the impacts of salmon farms on the marine environment?
How do sea lice from fish farms attack wild fish?
What chemicals are used to treat farmed salmon?
Is there any difference between organic and non-organic salmon?
Isnít salmon farming important for the economy?

Are farmed salmon the same as wild salmon?

They are not. Farm salmon are exposed to artificial processes to increase their growth rate rapidly marketable size. As smolts they are transported to sea in well-boats, or slung in containers beneath a helicopter. According to the Scottish Executive a farm salmon can be distinguished from a wild salmon by deformities: ragged fins, foreshortened head and damage to gill covers.

The life span of a standard farmed salmon ranges from 18 months to 2 years, and up to 2 to 3 years for a so-called organic salmon. By slaughter-time farm fish weigh approximately 6lb and measure upwards of 24 inches in length. Wild salmon of the same age are still in their natal stream and weigh only a few ounces.

Farm salmon lead lazy lives; food delivered to their mouths, little danger of being attacked by predators. The result is that a farm salmonís flesh can be flabby. A wild salmonís flesh is firmer because of its natural life-style. Fat lines on a farmed salmon are whiter and wider than those on a wild salmon.

During their lives wild salmon swim thousands of miles from the streams that gave them birth to their Greenland feeding grounds. Only the fittest survive this hazardous journey and return to spawn. Farm salmon remain in cages that can contain more than 70,000 fish.

What are the impacts of salmon farms on the marine environment?

I believe that salmon farming is responsible for adverse impacts on the marine environment. Diseases and parasites such as sea-lice and escapes of farmed salmon have damaged wild salmon and sea-trout populations in the West Highlands and Island of Scotland.

According to figures released by the Fisheries Research Services, an arm of the Scottish Executive, during 2005 less than 600 wild sea-trout were caught in the West Highlands. Prior to the advent of factory-salmon farming Loch Maree alone produced upwards of 1,500 sea-trout each season, whilst other West Highland lochs such as Eilt, Shiel and Stack could each produce upwards of 1,000. There are few fish left in these waters now because, I think, of the impact of fish farm sea-lice.

In the same area, prior to the arrival of fish farms, rivers such as the Dionard, Laxford, Inver, Kirkaig, Ewe and other West Highland streams accounted for nearly 10,000 salmon and grilse each season. Because of the impact of fish farm sea-lice, fewer than 2,000 are taken today.

Each year hundreds of thousands of farmed salmon escape from their cages. These farmed fish compete with wild salmon for a finite food and spawning resource. Scientific research has shown that in a few generations escaped farm salmon will out compete and replace wild salmon.

How do sea lice from fish farms attack wild fish?

Sea-lice occur naturally in the sea where they are not a problem for wild salmon. Sea lice that have attached themselves to a wild fish die when the host fish enters fresh water. Farmed salmon, however, never enter fresh water. After smolting they are confined in the sea for the whole of their lives. A salmon farm site may hold twenty cages containing more that 1 million fish.

Salmon farm cages act as a magnet for sea lice and they breed there in their billions. Sea lice are free-swimming and move on tidal currents. Therefore, as wild fish pass by the cages they are confronted with clouds of sea lice which then attach themselves to the wild fish. More than 12/15 sea lice can kill a wild fish.

Sea-trout are at greater risk because, unlike salmon, they do not migrate vast distances, but generally remain close to the shore and near to the rivers that gave them birth. As such, they are exposed to more constant sea lice attack, not only from cages at the mouths of their rivers, but also from other salmon farms in the vicinity.

It would be appropriate to refer to these fish factories as sea lice farms, rather than salmon farms. However, in spite of scientific evidence which shows that sea lice kill wild fish, the industry and the Scottish Executive refuses to accept that this. In my view, sea lice from fish farms are a primary cause of the collapse in wild salmonid populations in the West Highlands and Islands of Scotland.

What chemicals are used to treat farmed salmon?

Throughout their life, from birth to slaughter, farmed salmon are treated with a range of chemicals to protect them from disease and to make them more attractive to consumers. The flesh of wild salmon is naturally pink, because of the food they eat in the wild. Factory-farmed salmon flesh, however, is muddy grey in colour. Most farm salmon are fed a manufactured colourant in their food to make their flesh colour more appealing to consumers.

Common diseases on Scottish fish farms include Infectious Salmon Anaemia, Bacterial Kidney Disease and Infectious Pancreatic Necrosis, all of which can be fatal to caged salmon. Because of the numbers of fish stocked into each cage, disease spreads rapidly and is as quickly transferred to adjacent cages in the same sea loch.

Factory-farmed salmon have been identified by scientists as containing potentially harmful levels of PCBís and dioxins. A recent report advised people to limit the quantity of farmed salmon they ate to no more than four meals a year.

Much of the contamination in farmed salmon comes from the concentrated food fed to these fish. This is sourced from small, base-of-the-food-chain species that have accumulated high levels of contaminants from where the live; sandeels, Norwegian pout and capelin, for instance, from the polluted waters of the North Sea.

These PCBís and dioxins are thus passed on to farm salmon. Wild salmon may also have levels of PCBís and dioxins, but because of the wide range of their feeding grounds, these levels are lower than they are in farm salmon.

Industrial fishing also has an adverse impact on other species. Cod, mackerel and herring predate on sandeels, as do wild salmon and sea-trout and a wide range of sea birds. In recent years cod stocks in particular are so depleted than scientists advise a complete ban of commercial fishing for that species. There have been wide-spread breeding failures of sea birds because there is nothing for parent birds to feed to their young.

The small fish are mashed up to provide protein to be fed to farm animals and farm salmon. Research suggests that it takes three tonnes of these small fish to produce one tonne of farmed salmon. I believe, therefore, that it is a myth to claim that fish farming reduces the pressure of wild stocks. I think that exactly the opposite is the case. Fish farming is driving wild stocks to extinction.

Is there any difference between organic and non-organic salmon?

So-called organic farmed salmon is little different from standard farm salmon. The fish are stocked at lesser density, but even then this can mean that there are 6 to 7 fish in every cubic metre of water in their cage.

To turn the colour of organic salmon flesh pink, organic salmon can be fed off-cuts, residue and offal from other fish species that have already been processed for human consumption. Organic farmers claim that this does not impact on wild fish stocks because these fish have already been killed for human consumption.

What happens when supplies of fish offal run out at fish processing factories remains to be seen. It is suggested that fish farmers might then substitute this source with vegetable protein. However, studies have shown that the use of vegetable protein will reduce the levels of omega 3 fatty acids that fish farmers claim as being a primary benefit of eating their product.

Isnít salmon farming important for the economy?

Most salmon farming in Scotland is undertaken by foreign-owned companies, primarily Norwegian. 95% of all the farmed salmon produced in Scotland comes from a single, Norwegian-owned multi-national company which is now the biggest salmon farmer in the world.

Salmon farming does create some jobs in the Highlands and Islands, but these jobs are declining in number as farms become more automated and production shifts away from Scotland to other countries such as Norway, Chile, South Africa, Australia and New Zealand where there is perhaps less environmental scrutiny, or significantly lower production costs.

Chile, for instance, looks set to overtake Norway as the largest producer of farm fish. However, the damage caused to wild salmon and sea-trout has led to significant job losses in the West Highlands and Islands of Scotland where rod and line fishing has historically been so important to these remote areas.

Rather than providing sustainable employment in these areas, I believe that salmon farming has destabilised once stable communities. Over the past four years, thousands of jobs have been lost in salmon farming and this trend shows little sign of abating. Also, much of the raw material required by the industry is brought in from overseas Ė feed, fish, equipment Ė and little of the revenue generated, other than wages, stays in the communities.

I honestly believe that the harsh reality of salmon farming is that it is inherently unsustainable, damaging to wild fish populations and a threat to the health and wealth of our oceans.