ÐÓ°ÉÔ­´´

BOBBING on the remote sea waters of Loch Torridon in Wester Ross are
lines of rectangular rafts. These are some of the bank vaults containing
Scotland’s new wealth of living silver: farmed salmon. Up and down the West
Highland coast, round the Isle of Skye and the Western Isles, there is hardly
a sea loch left that does not have its conspicuous sea cages packed with
Atlantic salmon.

The industry has burgeoned in the past four years. In 1984, Scottish
salmon farms produced a mere 2500 tonnes of fish. In 1988, production reached
19 500 tonnes and this exponential increase is set to continue. The Department
of Agriculture and Fisheries for Scotland (DAFS) forecasts that the total
will reach 54 000 tonnes by 1990. Only Norway produces more. In Canada,
Iceland and Chile, the industry is still at the early stages and Ireland,
with 19 farms producing some 3000 tonnes of fish, is not yet a serious rival.

But while politicians count the benefits of 1100 new jobs in the Highlands,
others are less enthusiastic about salmon farming. Conservationists are
concerned about the almost total lack of statutory planning controls on
the industry. And scientists are worried about the impact such a rapidly
mushrooming business could have on the marine and freshwater environment
and on wild salmon. The wild salmon of Scottish waters probably amount to
between 15 and 20 per cent of the world’s wild stocks.

ÐÓ°ÉÔ­´´s still know very little about the effects salmon farms will
have on the ecosystem in the long term. Each cage can hold many tonnes of
fish, which have to be fed. By 1990, the Scottish industry will consume
184 000 tonnes of sand eels, sprats and other prey essential to the survival
of wild salmon and seabirds such as puffins and guillemots. The sand eels,
dried and compressed into pellets, are not so nourishing as they are when
fresh so each pellet contains a supplement of 15 vitamins, 11 minerals and
the synthetic colouring canthaxanthin (E161g). This colouring, banned in
the US, makes the flesh of the fish pink like that of wild salmon, rather
than ‘hatchery grey’.

The fish and the cages are kept clean with chlorine, sodium hydroxide,
iodophors (a solution of iodine) and calcium oxide. Disease is kept at bay
with formaldehyde, malachite green and four common antibiotics. No one knows
what the combined effect of these substances might be, but the use of another
chemical, Nuvan, is giving cause for alarm. Nuvan’s active ingredient, dichlorvos,
kills the parasitic salmon louse, Lepeophtheirus salmonis. It is also toxic
to crabs, shrimps, lobsters and mussels, and has been linked to the sudden
increase in the incidence of cataracts in wild fish.

ÐÓ°ÉÔ­´´s from the Nature Conservancy Council (NCC) and the University
of Stirling have studied the impact of pollution from salmon cages. They
found that for every 10 tonnes of feed, 1 tonne of solid waste sinks to
the seabed and a further half tonne of soluble nitrogenous compounds enters
the water column. To metabolise these extra substances, the microscopic
organisms that live in and on the sediment of the seabed around the cages
need more oxygen. When the oxygen runs out, the organisms die, often to
be replaced by a uniform growth of the bacterium Beggiatoa. Similarly, algae
in the water column multiply in the presence of the extra nitrates. When
the algae die, the bacteria that break them down multiply and consume more
oxygen from the water. Worse for the salmon farmer, some types of algae
that ‘bloom’ in this way are poisonous to the fish. Such problems are exaggerated
in the sheltered shallow waters of sea lochs, where the cleansing flushes
of the tides are weak.

Fish farmers increasingly take such factors into account when they select
a site for their cages. But the question of the long-term effects remains
unanswered. Could the balance of species within bottom-dwelling communities
change after many years of farming on such a large scale, and with what
result? No one knows. Nor do biologists know whether the concentration of
predators attracted to fish farms, such as crabs and starfish, will influence
the distribution and behaviour of other animals in the sea lochs.

Some fish biologists are particularly concerned about the threat salmon
farming may pose to wild fish. Each spring and summer, a proportion of the
Atlantic salmon feeding around Greenland and the Faeroes head home for their
natal rivers. Each year, fewer fish make it. Statistics from the sea fishery
show a slight but steady decline in the numbers of salmon caught at sea,
enough to worry the North Atlantic Salmon Conservation Organisation (NASCO)
to which all countries with breeding stocks belong. Since its foundation
in 1982, NASCO’s main concern has been with controlling indiscriminate marine
netting. Around Greenland, 75 per cent of the fish caught are females; and
off the west coast of Ireland the illegal use of invisible monofilament
nets is devastating stocks. Many regarded salmon farming as a means to save
the wild salmon because it would reduce the value of wild fish. But this
has not happened yet. Instead, farming threatens wild fish with diseases
that develop in the confined quarters of a fish cage. There is also a risk
that if enough farmed salmon escape, or are released, to the wild they will
reduce the genetic diversity of the species by interbreeding with wild fish.

Norwegian fish farmers have suffered from an appalling outbreak of Gyrodactylus,
a parasitic fluke. Nothing as bad has happened elsewhere, but dense concentrations
of fish in farms are bound to act as stew pots for disease. In 1988, two
of the nine farms crowded into Loch Sunart in Ardnamurchan suffered outbreaks
of the bacterial disease furunculosis. Fish farmers have to be continually
on guard against bacterial kidney disease, the viral disease infectious
pancreatic necrosis, and many protozoan, fungal and parasitic infections.
In Britain, the import of live salmonids is prohibited under the Diseases
of Fish Act 1937 and the import of eggs is strictly controlled. Movement
of ornamental fish is less restricted, however, and there is always a slight
risk that salmonids could enter the country by mistake with ornamental species,
and perhaps introduce foreign diseases.

A swim on the wild side

In every country that breeds salmon, farmed salmon reach the wild by
escaping from sea cages or because farmers release them deliberately or
to restock rivers from freshwater hatcheries. An increasing number of scientists
point to the threats escapees could pose to wild salmon in the short term
by competing for food, and in the long term by diluting the discrete genetic
strains of wild fish through interbreeding.

According to the Scottish Salmon Growers Association, the number of
escapees is negligible, but the evidence suggests otherwise. In 1987, Peter
Maitland, a fish biologist, reported one mass escape involving 90 000 fish.
In the same year, a group called Restoration of Atlantic Salmon in America
estimated that, on average, 15 per cent of farmed fish escape. In 1986,
a census of the fish feeding in the open sea around the Faeroes revealed
that 3 per cent of the fish were from farms, identified by the presence
of canthaxanthin in their tissues.

In Scotland, no one keeps records of the number of farm smolts and parr
that are dumped into rivers. The District Salmon Fisheries Boards have the
power to control such releases but in practice are happy to buy unwanted
farm fish to restock their rivers.

The possibility of genetic deterioration in wild stocks is becoming
as worthy of investigation in Scotland as it is in Norway. The wild salmon
bases its whole life strategy on subtle flexibility. To avoid one-off calamities,
there are fish that become smolts in one, two or even three years, and that
mature at sea as ‘grilse’ in one year or between two and four years. The
salmon breeds in 375 rivers in Scotland and at least 1700 rivers elsewhere
in the world. Geneticists are now certain that each river contains one stock,
if not more, that is genetically unique. So far, scientists have found 17
points on the salmon’s chromosomes that are genetically variable: in other
words, there are at least 17 ways that the stocks can differ from each other.
These variations increase with distance between stocks. Research suggests
that these discrete genetic fingerprints are probably not the result of
random variation but of natural selection. As such, they are more likely
to be significant to the survival of each stock within its own river.

Maitland recommends the establishment of a salmon register, a database
to keep tabs on salmon stocks and to ensure that in restocking programmes,
at least, the right strains of fish go into the right rivers. The register
would include an inventory of known introductions of salmon to each river
system. Such a project is already under way in North America.

In view of the environmental concerns aroused by the enormous expansion
of salmon farming in Scotland, it is surprising how few controls are imposed
on the industry. There are no national planning guidelines for fish farms.
Nor is there any democratic scrutiny of decisions on where to site new farms.
This is because the whole of the seabed within the boundaries of the United
Kingdom and below the level of a spring low tide, belongs to the Crown.
The duty of the Crown Estate Commissioners, who administer these areas,
is ‘to maintain and enhance the capital value of the estate and similarly
the income obtained from it’. Leases on the seabed, which usually run for
15 years, cost salmon farmers about Pounds sterling 50 per tonne of production.
In 1989, the leases are expected to earn the Crown estate almost Pounds
sterling 2 million.

Last year, Scottish Wildlife and Countryside Link, an umbrella organisation
representing 12 voluntary conservation groups, published a report on marine
fish farming in Scotland. It criticised the Crown Estate Commissioners for
being concerned mostly with development and for asking for too little information
of those who apply for leases. The report also criticised the commissioners
for allowing too short a period of consultation with concerned bodies, and
for making decisions permitting no further consultation and no appeal. According
to the report, the commissioners lack the expertise and manpower to enforce
the conditions attached to the leases.

In effect, the commissioners are required by current legislation to
guide and police the development of a huge new industry, of which they are
also the beneficiaries. Conservationists are not the only people who complain
about the system. Some District Salmon Fisheries Boards, which are responsible
for stocks of wild salmon in rivers, have voiced their dismay when they
found salmon farms sited in the mouths of their rivers without any consultation,
or even notification. A new report, commissioned from the Institute of Aquaculture
in Stirling by the Nature Conservancy Council, expresses many of the criticisms
listed by Link. In particular, the institute recommends that the procedure
for siting salmon farms should be brought under some sort of democratic
control. Despite widespread support, however, this idea has recently been
quashed by Malcolm Rifkind, Secretary of State for Scotland.

The planning status of hatcheries in freshwater is even more of a mess.
Some local authorities class inland fish farms as agriculture and so outside
the remit of planning controls. The Scottish Development Department has
stated that this should not be the case, but until the law is clarified,
the confusion could have serious repercussions. For example, pollution of
the upper reaches of salmon rivers could devastate wild breeding stocks.

Salmon farming brings new industry to remote communities which is why,
in many cases, the Highlands and Islands Development Board and the EEC will
cover 70 per cent of the cost of establishing a fish farmer. But perhaps
Scotland should look to the Shetland Isles for an example. In the Shetlands,
applications for sites are under the democratic control of the Islands Council.
A local proprietor must own 51 per cent of the operating company, and there
are specific policies for conservation. A recent study has shown that the
industry supports three times as many local jobs as it does in the rest
of Scotland. In 1988, half the production from 370 Scottish sites was concentrated
in the hands of just three companies.

Stephen Mills is a writer and film maker based in Oxford.