European Cetacean Bycatch banner loading

"Man is but a strand in the complex web of life"

Internal links buttons



The Scottish Parliament Transport and the Environment Committee11th Report 2002
Report on Phase 2 of the Inquiry into Aquaculture
Volume 2: Evidence

SP Paper 611 ~ Session 1 (2002)


The report reveals the serious fish welfare problems arising from intensive salmon and trout farming. We believe that far-reaching reforms are needed to end the detrimental impact on welfare of fish farming.

Our principal concerns include

Overstocking, leading to fin and tail injuries, disease and high mortality rates

Salmon are kept at significantly overcrowded densities. The Salmon Farming Handbook, 1988, states that salmon are genetically programmed to spend most of their lives swimming freely through the oceans. In the cages of the fish farm they are in close proximity to, and have frequent physical contact with thousands of others. In the open seas they would probably never have come as close to any other fish of their own kind before returning to spawn.

In the crammed conditions of fish farming cages, salmon swim as a group in incessant circles around the cage, rather like the pacing up and down of caged zoo animals. Fins and tails become worn and damaged as the fish rub against the cage sides or each other.

The stress of crowding and confinement can manifest itself in salmon in an increased susceptibility to disease and high rates of mortality. Mortality rates average 10-30% during the sea-rearing stage alone. Salmon have, in recent years, suffered from a high incidence of severe cataracts, which often cause blindness, and disease outbreaks such as furunculosis and infectious salmon anaemia.

Trout are stocked at even higher densities and, like salmon, suffer high levels of injuries to fins and tails.

Compassion in World Farming (CIWF) believes that maximum stocking densities should be laid down by law.

Parasite infestation

Intensive farming has led to sea lice being a major problem for salmon. These feed on their host, causing fish to lose skin and scales and, in the worst cases, die. Lice damage around the head can be so severe that the bone of the living fish's skull can be exposed.

Current treatment centres on the use of chemicals such as organophosphates and synthetic pyrethroids. These may have detrimental environmental effects. Other seemingly "environmentally-friendly" treatments such as bathing in hydrogen peroxide, or using another fish species, wrasse, to eat the lice off the salmon, have serious welfare drawbacks. Hydrogen peroxide is a chemical irritant and highly aversive to salmon. As regards wrasse, they suffer from starvation, being eaten by the salmon or dying from the stress of capture and transport to the farm.

Starvation and slaughter

Farmed fish are normally starved for about 7-10 days before slaughter. It is claimed that this empties the gut and minimises the risk of the flesh becoming contaminated when gutted. However, gut clearance only takes 24-72 hours. Starvation for more than 72 hours should be prohibited.

Some slaughter methods cause great suffering. Many trout are slaughtered by suffocation in air or on ice; in the latter case trout can still feel what is happening to them almost 15 minutes after being taken out of the water. Also inhumane are carbon dioxide stunning of salmon and trout and cutting the gills without pre-stunning. Such methods should be prohibited.


After being reared in freshwater tanks, cages or ponds, juvenile salmon are transferred to sea farms by lorries, helicopters or boats. Similarly, trout may be transported from the hatchery to the rearing farm or for slaughter. Movement and transfer can be a frightening experience for fish and causes considerable stress.

Biotechnology and genetic engineering

We have a range of concerns in this field. The production of `triploid' fish is widespread in the trout industry. Newly fertilised eggs are subjected to heat or pressure shock so that cells carry three sets of chromosomes instead of the normal two. This causes the resulting fish to be sterile, thereby delaying sexual maturity and the resulting reduction in flesh quality. It also causes significant health and welfare problems. Triploid fish have been found with higher levels of spinal deformities and breathing difficulties and higher mortality rates.

Genetic engineering for faster or larger growth has also led to serious health and welfare problems for fish. Although the Scottish industry is largely opposed to genetic engineering, commercial pressures could lead to it being used; accordingly, CIWF believes the genetic engineering of fish should be prohibited.

Wildlife slaughter

Conflicts have arisen between fish farms and wildlife, resulting in poor welfare for both fish and wildlife alike. Fish can become severely stressed and injured by attacks from seals and predatory birds. Some fish farmers have seen the killing of wild animals as a legitimate part of predator control. An estimated 3,500 seals are killed around Scottish fish farms every year.

Other farmed fish species

Cod, halibut and turbot farming have already started. Similar welfare problems will probably arise in the farming and slaughter of these species as are experienced for salmon and trout. Accordingly, the farming of these new species should be halted before they become established.
Peter Stevenson,
Political and Legal Director
Compassion in World Farming
CIWF Report 2001

To download the above mentioned file from an alternative site, please click here.