Wild salmon and salmon aquaculture - EAA's position
More than 1.4 million metric tonnes of
farmed salmon are produced in Europe
annually (1.2 million in Norway alone in
2012). This equates to approximately 450
million salmon being held in pens or net
cages. These salmon farms are often located
in the river estuaries and threaten the very
survival of wild Atlantic fisheries due to
infestation with sea lice and millions of
With approximately 1,000 times more
farmed salmon than wild salmon in the sea,
and the farmed salmon being in coastal
waters year round, the production of natural
parasites such as sea lice Lepeoptheirus
salmonis) is far in excess of natural levels.
Remedial treatment using chemicals to
reduce the number of sea lice parasites have
proven damaging for the environment and
unsuccessful. Areas with intensive salmon
farming pose a serious threat to wild salmon
and sea trout habitat. A single farm aqua
pen can contain up to 0.2 million salmon in
Norway (this is the Norwegian legal max.
limit). In comparison the total return of wild
salmon to Norway is approximately 0.5
million. Escapees from a single salmon farm
pen can therefore cause dire consequences
in nearby salmon stocks. An Irish proposal
for Galway Bay includes 72 open pens with
an annual stocking programme of 7.2 million
smolts in total at peak stocking levels.
Farmed salmon is not a
natural part of the ecosystem
Escaped fish from farmed cages are
threatening the wild Atlantic salmon in many
In the sea, the escaped salmon spread sea
lice to wild salmon and sea trout. In the
rivers, the farmed salmon interfere with the
spawning process of the wild salmon and
weaken the native wild strain as interbreeding
reduces to the genetic fitness of adult wild
salmon. If this is allowed to continue year
after year, the result will be a diluted gene
pool and reduced longterm survival of
salmon and sea trout stocks, which are
genetically unique in each river.
Local salmon stocks have for generations
adapted to the changing conditions in the
different rivers, and developed specific
adaptations to suit their rivers. Farmed
salmon however, are genetically different
after several generations of selective breeding
for commercial exploitation.
Interbreeding between wild and farmed
salmon, will over time lead to diluted stock
quality, with less ability to respond to the
particular conditions in each river. The result
will be that fewer parr and smolts will be
produced in the rivers. The worst case
scenario is the extinction of unique traits, and
even unique salmon stocks in the future, due
to this harmful influence from escaped farmed
In several rivers the percentage of farmed
salmon is much higher than what scientists
suggest is a safe limit (under 5%). In the
country with the largest salmon industry,
Norway, the average number of farmed
salmon at the breeding grounds is 15% -
more than three times higher than the official
safe level. This must not be allowed to
Sea lice occur naturally in sea water, and prior
to fish farming were of no significant threat to
wild salmon, sea trout and sea-run char.
However, because of the enormous amount of
hosts held in fish farms throughout the entire
year, an abnormally high concentration of sea
lice has developed in coastal areas where fish
farming is taking place. hen the small
smolts leave their rivers and migrate to the
Atlantic Ocean to feed, they pass numerous
fish farms on their way. Due to the large
number of hosts in the pens, the sea lice
concentration is often very high even when
the salmon farmers treat their fish against sea
lice infections. In some areas even an
infection of one lice per 10 salmon in the pens
adds up to a total number of lice that is
unsustainable for wild salmon populations. 8-
10 lice on a salmon smolt are lethal. Some
areas off the Norwegian coast have
experienced up to 95% mortality of migrating
wild smolts due to sea lice emanating from the
fish farm cages.
Chemical treatments are used to contain the
population of sea lice in salmon farms, which
works initially, but after some time the sea lice
become resistant to treatment and without
effective treatment, the population of sea lice
is set to explode. This will have grave
consequences for wild fish unless such
dangerous fish farming practices are replaced
with floating or inland closed and contained
farms with effective barriers between the
farmed fish and the natural environment.
What does EAA want?
EAA proposes the following measures to ensure that sea lice, farmed salmon and rainbow trout
escapees do not threaten or drive our unique wild salmon and sea trout stocks
to extinction in the areas that are most severely affected.
Stop the escape of farmed salmon
Measures in the short term:
- Better monitoring of escaped salmon and their mixing with wild salmon.
- Limits and borderline values for frequencies of farmed salmon vs. wild salmon in rivers must be established to trigger action.
- A borderline value of less than 5% farmed salmon in river stocks must be implemented to initiate action against fish farms and removal of the threat of escaped fish.
- Escapees must be deemed unlawful and legal action against farms allowing escapes must be made more severe by all enforcement agencies in the Atlantic.
- Compulsory tagging of farmed salmon must be introduced, to enable the identification of the specific farm from which the fish have escaped. This tagging must include both an external (e.g. adipose fin clipping for fast recognition at site) and an internal tag (individual recognition back to site of escape).
- More measures to prevent escapes of salmon from farms must be introduced (e.g. by a more rigid construction).
- The exclusion of giant pens must be considered – as these pens can result in catastrophic escapes of salmon.
- To prevent genetic ‘pollution’ of indigenous (wild) salmon, only non-fertile (e.g. triploid) salmon should be used for mass-production.
Measures in the medium term:
- Move all salmon farming into closed & contained farms either floating on the sea or on land to eliminate escapes.
Stop the sea lice problem
Measures in the short term:
- The growth of the industry must be put on hold until it can be proven to be sustainable for the future survival of the wild salmon, sea trout and sea-run char.
- Governments must enforce a higher degree of surveillance and monitoring of sea lice on wild salmonids especially at the critical time when they migrate past aquaculture sites.
- When examinations show damaging levels of sea lice, immediate action must be taken to treat or remove stock from salmon pens.
- Reduction of sea lice from farms must be achieved without causing detrimental effects to the environment.
- Giant pens that prevent effective sea lice counting and direct sea lice treatment should be banned.
- Authorities must forcefully apply the Precautionary and the Polluter Pays Principles.
Measures in the medium and long term:
- Move all salmon farming into closed & contained farms either floating on the sea or on land to eliminate sea lice infestation of wild Atlantic salmon and pollution