Fish CAN feel pain
- All animals possessing a nervous system and pain receptors are capable of
suffering the effects of pain. This includes fish.
- Dutch researchers back in the 1980s showed that fish hooked by anglers
could experience pain. They found that carp hooked on a tight line were
prepared to starve themselves of food for quite some time afterwards to
avoid the painful experience. (1)
- Although there are marked differences in brain structure between fish and
mammals, they nevertheless both share important brain functions, including
responses to painkillers.
- Government advisory body the Farm Animal Welfare Council (FAWC)
acknowledges that fish experience fear, stress and pain when removed from
water, and that the physiological mechanisms in fish for experiencingpain are
very similar to those in mammals. (2)Similarly, an RSPCA-sponsored report
concluded that all vertebrates - including fish - experience similar sensations
in response to painful stimuli.
- Prolonged periods of stress can cause negative changes in the immune
system, making fish more vulnerable to disease. (3)
- In pain sensitivity experiments performed at Edinburgh's Roslin Institute,
fish had a toxin and acid injected into their lips. They exhibited 'rocking'
motion, similar to the way higher vertebrates - e.g. humans - rock to comfort
themselves. They also rubbed their lips against the tank walls and gravel,
and took three times longer than normal to resume feeding. (4)
- In tests at Oxford University, Mexican cave fish - genetically blind - built a
mental map of their surroundings by memorising the position of objects in
their tank. They quickly reacted to changes in the set-up. This task defeats
some small mammals, e.g. hamsters. (5)
- At the University of Edinburgh, spotted rainbowfish remembered how to
escape from a net in their tank 11 months after initially working it out. (5)
Fish on farms are caged in cruel and
- Overcrowding and the unnatural environment found in fish farms greatly
increase stress levels. As many as 50,000 salmon may be kept in each sea
cage. Trout are kept in even more crowded conditions.
- Such unnaturally high stocking densities also render the fish highly
susceptible to disease. (6)
- Salmon suffer from a number of parasites and other debilitating agents.
The most notable of these include sea lice, furunculosis and pancreas
disease. Lice infestation is a devastating condition that flourishes in farm
cages, literally eating the fish alive. Attempts to tackle some of these
diseases include the use of chemicals (such as malachite green and formalin)
- substances known to carry human health risks.
- Farmed fish are regularly dosed with chemicals and antibiotics to limit the
damage. (7)But between 20 and 50 per cent still die from diseases such as
cancer or pancreas and kidney infections.
- The number of chemical licences in the salmon industry approved by the
Scottish Environment Protection Agency (SEPA) increased sevenfold in the
four years up to 2001. SEPA approved just 45 uses of sea lice chemicals in
1998. That rose to 104 the following year, 141 in 2000 and a staggering 296
in 2001. (8)
- Wild salmon captured near salmon farms in Scotland, Ireland and Norway
carried an average of 100 lice per fish. Salmon captured away from farms
carried an average of 13 lice. (9)
Farmed fish are
- Before female fish are
anaesthetised for egg
extraction, their abdomen
is palpated to see if the
egg mass is free. This is
highly stressful and can
occur several times
- The eggs are stripped
either by hand or
compressed air is
introducedinto the body
cavity with a needle.
Sometimes the ovaries
may be removed surgically.
- Most females are killed
after their eggs have been
stripped, as waiting for
them to regain body
condition is uneconomic.
The breeding females are
treated as production
machines, as with other
farmed female animals.
The male fish are also
'milked' several times for
their semen before
Fish are genetically modified
- Researchers are developing genetic engineering techniques in an attempt
to produce fish who can grow larger and faster, convert feed into flesh more
efficiently, are resistant to disease, tolerant of low levels of oxygen in the water
and can stand freezing temperatures. As with all such GM animal procedures,
these techniques are highly experimental and will result in lots of failures and
pain and suffering for the fish involved.
- Biotechnology is widely used in Europe to manipulate the chromosomes of
fish reared for slaughter.
- Sex reversal - feeding testosterone to young breeding females - is used
to produce batches of all-female fish that will mature later than males. This
is done because sexually mature fish undergo changes that can reduce
- Triploidy (adding an extra set of chromosomes) is often used in conjunction
with sex-reversal to produce sterile all-female fish who show increased feed
efficiency and will not interbreed with wild populations if they escape.
- These genetic manipulation techniques have effects on the health and
welfare of the fish. Higher levels of spinal deformities have been found in
triploid rainbow trout. (10)Triploid salmon have lower survival rates and are
less able to absorb oxygen, making them less able to cope with stressful
situations. (11) & (12)
Fish are transported live
- Juvenile salmon and trout are transported live from hatcheries to a rearing
farm or for slaughter. They are transferred to and from their transport
containers by vacuum pumps, or by hand with the use of nets. Damaged
nets, or rough handling, injure the fish.
- Transport is either in a purpose-designed tank slung below a helicopter, by
road, or by sea in specially designed well-boats.
- Before transport, it is current practice to deprive fish of food for 48 hours or
more. This reduces faecal contamination of water in the transport tank and
reduces oxygen consumption, since starving the fish slows down their
- Movement and transfer can be a frightening experience for fish and has
been described as causing 'considerable' stress. (13)
- Major losses occur in farmed trout as a result of accidental oxygen
deprivation (notably while being transported).
Farmed fish are killed without prior stunning
- In some units, the fish are killed by first being hit on the head with a club and
then having their gill arches torn or cut so that they bleed to death. In other
operations, the fish are placed in a carbon dioxide tank and then clubbed or
are bled to death.
- Slaughter regulations stipulate that farmed animals killed for meat should
be stunned before having their neck cut, in order to prevent suffering,
but this does not apply to fish. Killing methods currently in use allow
exsanguination (bleeding out) without prior stunning, resulting in convulsions
and muscular spasms.
- Whereas salmon may be clubbed before being killed, trout are too small
and are left to die of asphyxiation. Some recover consciousness before
evisceration (removal of internal organs). (7)Fish farmers themselves have
admitted that 'letting tens of millions of fish die of suffocation each year is
- It is an offence for any person involved in the slaughter of farmed fish to
cause or permit fish to sustain any 'avoidable' excitement, pain or 'suffering'.
The use of the word 'avoidable' gets round the fact that the entire process of
handling and killing the fish in itself causes pain and suffering. Furthermore, no
monitoring whatsoever takes place at sea.
Wild caught fish also suffer greatly
- Vast drift nets, some 40 km long, are used to trawl the seas. Fish can
be dragged along the ocean bed for hours within these nets, trapped
alongside rocks, debris and other sea life that has fallen in the net's path.
- When hauled up from the deep, fish undergo excruciating decompression.
Frequently, the intense internal pressure ruptures the swimbladder, pops out
the eyes, and pushes the oesophagus and stomach out through the mouth.
- Caught fish are sorted using small, spiked rods called pickers. Factory ships
slaughter and process the fish at sea. Most fish are gutted whilst still alive or
are left to suffocate.
- A Dutch study on fish industry slaughter methods found that after gutting
25 - 65 minutes elapsed before fish were insensible (failed to show
co-ordinated swimming or responded to stimuli but showed brain stem
responses like breathing). In the case of asphyxiation, 55 - 250 minutes
elapsed before fish were insensible. (15)
- Unlike the British fishing industry, the Dutch are taking steps towards
improving fish slaughter methods. The Dutch study recommended a general
term of reference for the length of time in which a fish should be killed -
1 second - to prevent suffering. This recommendation is under discussion with
a view to including it in animal welfare legislation. Killing fish on a large scale
within 1 second is complicated and so the study recommends the stunning of
fish prior to killing. Although Animal Aid promotes an animal-free diet, while fish
continue to be caught and killed, genuinely effective stunning would be a step
in the right direction in an industry currently without welfare protocols.
- 1987. Do fish have feelings?New Scientist.
- FAWC. 1996. Report on the welfare of farmed fish.Defra.
- Pickering AD and Pottinger TG (1989) Stress response and disease
resistance in salmonid fish: effects of chronic elevation of plasma cortisol.
Fish Physiology and Biochemistry7: 253-258.
- Sneddon, L.U et al.2003. Do fish have nociceptors: evidence for the
evolution of a vertebrate sensory system.Proceedings of the Royal Society
Series B: Biological Sciences. Vol. 270, No. 1520.
- Matthews, R. 2004. Fast-learning fish have memories that put their owners to
shame.The Sunday Telegraph.
- DEFRA www.defra.gov.uk
- Lymbery, P. 2002. In Too Deep - The Welfare of Intensively Farmed Fish.CIWF.
- Feb. 2002. Salmon Farms 'a licence to pollute'.Scotland on Sunday.
- 2004. Sea Lice and Salmon: Elevating the dialogue on the farmed-wild salmon
story.Watershed Watch Salmon Society.
- Madsen, L., Arnbjerg, J. and Dalsgaard, I. 2000. Spinal deformities in triploid
all-female rainbow trout (Oncorhynchus mykiss). Bull. Eur. Ass. Fish Pathol., 20
- Johnstone, R. 1992. Production and performance of triploid Atlantic salmon
in Scotland.Marine Laboratory, The Scottish Office Agriculture and
- Willoughby, S. 1999. Manual of salmonid farming.Fishing News Books,
Blackwell Science, Oxford.
- Shepherd, J. and Bromage, N. R. 1988. Intensive Fish Farming.BSP
Professional Books, Oxford.
- Brown, A. 2003. Stunning fish before death considered by EU.The Times.
- V.d. Vis and Kesten. 1996. Killing of fishes; literature-study and practice-
observations (field research) report number C 037/96, 1996 RIVO DLO.
Click here for part 3 of The Fishing Industry.