PAIN AND FISH WELFARE

Welfare of Farmed Fish

Welfare of Angled Fish

WELFARE OF FARMED FISH

• FROM SMALL SCALE, EXTENSIVE TO LARGE SCALE, INTENSIVE FARMING

Heavy investment in research and development from the late 1960s onwards helped solve water control and management problems associated with fish farming; enabled fish to be grown rapidly at economic rates; and aided the formulation of complete compound fish diets (Lymbery, 1992). Industrial efficiency was taken further by the development of vaccines to control fish diseases, the ability to determine the sex of fish and control the reproductive cycle, and more suitable strains for farming are produced by selective breeding programmes (Lymbery, 1992). The vast majority of the 70 million fish produced annually in the United Kingdom are reared intensively, whereby large numbers are confined in a small area, causing serious welfare problems (Lymbery, 2002).

• WHAT IS ANIMAL WELFARE?

The welfare of an individual animal has been described as "its state as regards its attempts to cope with its environment" (Fraser and Broom, 1990). Animals under poor welfare often show abnormal patterns of behaviour and can be more prone to disease. In fish, disease or ill health are common indicators of poor welfare (Lymbery, 2002).

• FISH REARING AND WELFARE

1. Production life cycle:

• Female fish are selected for breeding and closely monitored for ripeness, which comprises light sedation by administration of a controlled concentration of anaesthetic to facilitate handling and palpation of the abdomen to see if the egg mass is free. The main anaesthetics used are benzocaine (dissolved in a solution of acetone), phenoxyethanol and MS222 (FAWC, 1996). Females which are found ready for stripping are anaesthetised by immersion in a tank containing anaesthetic solution.

  Male fish are generally anaesthetised before milking (extraction of milt).

2. Equipment and tanks:

• Injuries to the snout and fins of fish are relatively common and readily noticed in cages (FAWC, 1996). Nets should be designed to minimise abrasion to limit skin or fin injuries.

3. Stocking density:

• Atlantic Salmon (Salmo salar) – usually stocked at 15 – 20kg/m³ (FAWC, 1996)
• Recommended stocking density – 10kg/m³ (CIWF, 2002)
• Rainbow Trout (Oncorhynchus mykiss) – usually stocked at 30 – 40kg/m³ (FAWC, 1996)
• Recommended stocking density – 20kg/m³ (CIWF, 2002)

• At high stocking densities fish show abnormal behaviours such as increased aggression; have widespread injuries, deformities and disease; develop blinding cataracts; and have high parasitic infestations and mortality rates (Lymbery, 2002).

• Injuries may also arise from collision or aggression between fish (FAWC, 1996).

• Willoughby (1999) has shown that advanced stages of cataract can cause bleeding and damage to the cornea, as well as blindness.

• Diseases include Furunculosis, Bacterial Kidney Disease, Vibriosis and Infectious Salmon Anaemia. These are responsible for the deaths of millions of fish either directly or through slaughter programmes designed to control them, as there is a limited availability of veterinary medicines for treatment in fish (Lymbery, 2002).

• Sea lice are the single most important problem affecting the welfare of farmed fish. They feed on the blood and underlying tissues of the host causing skin and scale loss. Lice damage around the head can be so severe that the bone of the living fishes’ skulls can be exposed – a condition referred to as the "death crown" (Lymbery, 2002). Treatments involve bathing the fish in a chemical solution, feeding an oral pesticide, or using "cleaner" fish such as Wrasse to eat the lice off affected fish (FAWC, 1996).

4. Grading:

• Fish grow at varying rates, and under confined conditions, larger fish may bully smaller ones, or even cannibalise each other. To minimise this, fish are graded into different sizes, which involves netting or pumping them out of the water and over a series of bars, with smaller ones falling through the slats (Lymbery, 2002). This can cause physical damage such as scale loss and abrasions, and be very stressful for fish.

5. Transport:

• Transport is usually by well-boats, helicopter & bucket or lorries. The nets in the transport containers should be designed to eliminate physical damage to the fish.

6. Slaughter:

• - Legislation: The Welfare of Animals (Slaughter or Killing) Regulations 1995

  The general provisions make it an offence for any person engaged in the movement, restraint, stunning, slaughter or killing of fish to cause any, or permit any, fish to sustain any "avoidable excitement, pain or suffering".

  - FAWC (1996) states that "stunning must cause immediate loss of consciousness which lasts until death, fish must not be stunned unless they can be bled or otherwise killed without delay and, if fish are to be killed without prior stunning, any method used must result in rapid and irreversible loss of consciousness. In this context the relevant aspect of consciousness is sensibility to pain, fear or distress".

  - Slaughter methods (CIWF, 2002):

• Percussive stunning by blow to the head – carried out manually using a hand-held club called a "priest" for stunning, followed by cutting of the gill arches to bleed the fish. Care is needed to ensure that worker fatigue does not lead to inaccurate or ineffective stunning.
• Carbon dioxide stunning – fish are placed in a seawater bath saturated with carbon dioxide. This environment is highly aversive with fish being observed to shake their heads and tails vigorously trying to escape (Robb et al., 2000). Movement ceases after 30 seconds, but sensibility may not be lost for 4 – 5 minutes (Robb et al., 1997). Bleeding after CO₂ stunning is essential to avoid fish recovering. If fish are removed early from the stunning tank, they are likely to have their gills cut when immobile but still conscious.
• Bleeding without prior stunning – gill arches are cut with a knife and fish bleed to death. After gill cutting, the fully conscious fish react vigorously, and cease moving after 4 – 7 minutes (Wall, 1999; Robb et al., 2000). The FAWC (1996) states that it is reasonable to assume that early convulsive movements and muscular spasms are reactions resulting from pain or distress caused by the method and conscious attempts by the fish to escape the environment of the bleed-out tank.
• Electrocution – electric current is passed through the water containing the fish. The electric current must be sufficient to stun and kill the fish, otherwise the fish are only paralysed and could suffer considerably. This method can also cause spinal fractures and haemorrhaging.
• Asphyxiation in air or on ice – fish are hauled out of water and allowed to die through suffocation in air, a method which the FAWC (1996) states as unacceptable. Alternatively, they are removed from water into bins containing ice, which prolongs suffering, as the cooling effect of the ice can lengthen the time to unconsciousness. Kestin et al., 1991 show that fish ‘harvested’ this way can still feel what is happening to them 15 minutes after being taken out of water. FAWC (1996) recommends that this method should be prohibited.

7. Mutilations:

• Mutilations are relatively uncommon, but for identification purposes, fin clipping, whereby part of one of the fins is cut off, is sometimes carried out. External tagging which involves the attachment of a small plastic identification tag to the body, fins or gill cover is also carried out. Marking methods should only be used where they cause minimal damage to the fish, and mutilations which involves removal of sensitive tissue should not be carried out on farmed fish (FAWC, 1996).

REFERENCES:

• FAWC (1996) Report on the Welfare of Farmed Fish. Surrey: Farm Animal Welfare Council.
• FRASER, A.F. and BROOM, D.M. (1990) Farm animal behaviour and welfare. 3^rd ed. London: Bailliere Tindall.
• LYMBERY, P. (1992) The Welfare of Farmed Fish. Petersfield, Hampshire: Compassion in World Farming.
• LYMBERY, P. (2002) In too deep – the welfare of intensively farmed fish. Petersfield, Hampshire: Compassion in World Farming.
• ROBB et al., (1997) Welfare of Fish at Slaughter. Minutes of workshop held at the School of Veterinary Science, Langford, 4^th March 1997.
• ROBB, D.H.F., WOTTON, S.B., McKINSTRY, J.L., SORENSEN, N.K. and KESTIN, S.C. (2000) Commercial slaughter methods used on Atlantic salmon: determination of the onset of brain failure by electroencephalography. Veterinary Record, pp. 298-303.
• WALL, A.E. (1999) Fish Farming. In: Management and Welfare of Farm Animals. Eds: Ewbank, Kim, Madslien and Hart. London: UFAW.
• WILLOUGHBY, S. (1999) Manual of Salmonid Farming: Fishing News Books. Oxford: Blackwell Science.

WELFARE OF ANGLED FISH

ANGLING PRACTICES IN THE UNITED KINGDOM:

The word "angling" is usually defined as the means of taking fish or attempting to take fish by rod, line and hook (Medway, 1980). There are usually three types of angling in the UK.

1. COARSE FISHING:

• This involves fishing for coarse fish in inland waters (such as rivers, ponds and canals), and employs natural bait (substances edible to the fish) presented on tackle. Bait used includes larvae of several dipteran flies, bread, worms, cheese preparations, soft fruit, tinned meat, slugs, crayfish and stewed wheat or hemp (Medway, 1980). The 1970 National Angling Survey reports that 67% of British anglers participate in coarse fishing. Coarse fishermen aim to catch exceptional numbers of fish, exceptionally large fish, or a combination of both, for competition purposes (Medway, 1980). Typically, these fishermen are reluctant to kill fish, and insist on returning the catch live to the water after weighing, measuring and photographing it.

2. GAME FISHING:

• This involves fishing for freshwater game species, which include the salmon (Salmo salar), sea trout (Salvelinus fontinalis), brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). Traditional methods employ an artificial "fly" made from materials such as feather, silk, wool, fur and tinsel, and flies are usually dressed on single hooks, but doubles or trebles may also be used to hook two or three fish simultaneously (Medway, 1980). The 1970 National Angling Survey reports that 22% of British anglers participate in game fishing. It is usual to kill game fish for the table, and substantial re-stocking of game fisheries by hatchery-reared fish is standard practice (Medway, 1980). Fish are typically killed by the "coup de grace".

3. SEA ANGLING:

• Sea anglers operate from the shore, from piers and similar installations or from boats which may take them as much as 20 miles offshore (Medway, 1980). Sea angling techniques reflect those employed in fresh water, including the use of rods, tackles and artificial flies. The 1970 National Angling Survey reports that 47% of British anglers participate in sea angling. Sea anglers fish for a wide variety of species for competition purposes, and fish are delivered dead for weighing (Medway, 1980).

LICENSING AND QUALIFICATIONS:

• Freshwater angling throughout England and Wales is by licence, but only relates to the use of equipment, not to its procurement or possession. Licences are issued by regional water authorities and are freely on sale to all applicants (Medway, 1980). They do not stipulate instructional matter, beyond the regulations concerning seasons and size limits.

• In Scotland regulations governing fishing are administered by local fisheries boards and regulations governing the ways in which a fish can be taken are laid down in the Salmon and Freshwater Fisheries (Protection) (Scotland) Act 1951, but there is no licensing system.

• Traditionally, anglers are self-taught, although formal tuition is now available, followed by the award of a certificate of qualification by the National Federation of Anglers.

KILLING METHODS:

• The aim of every angler is to catch fish by means of a hook, single or multiple, impaled in the mouth. A fish hooked elsewhere in the body is termed "foul-hooked". Any hook causes tissue damage when it catches and thus, in medical terms, inflicts an injury, the extent and severity of which is likely to be increased by the use of double or treble hooks or tackles employing sets of multiple hooks (Medway, 1980). The existence of a rich innervation in the lips and mouth of fish (Medway, 1980) implies that this is painful to the fish.

The coup de grace

• Fish to be slaughtered following capture should be killed as quickly and painlessly as possible. This usually requires a blow to the head which should induce immediate unconsciousness during which fatal massive cerebral haemorrhage takes place, resulting in death (Medway, 1980).

• Very small fishes can be killed by being thrown hard on to the ground (Medway, 1980).

• Fishes such as eels and elasmobranchs (sharks and rays) should be killed by cutting the spinal cord at the back of the head with a sharp knife, which should result in clinical death although body-movement is likely to continue for some time afterwards (Medway, 1980).

• A commonly used alternative for middle-sized fish is to break the spinal column and also rupture branchial vessels by a sharp dorsal movement of the head, where a finger is usually inserted into the fish’s mouth, and pulled sharply up and back (Medway, 1980).

• It is therefore recommended that fish be unhooked from the line as soon as possible after capture and either returned to water immediately or that death be as nearly instantaneous as possible to improve the welfare of the capture and killing of angled fish by reducing the pain inflicted upon them.

REFERENCES:

• MEDWAY, LORD (1980) Report of the panel of enquiry into shooting and angling (1976-1979). Panel of enquiry into shooting and angling, Horsham, Sussex, UK: Royal Society of the Prevention of Cruelty to Animals.

ON TO LINKS

BACK TO CONTENTS

BACK TO AWRG PAIN RESEARCH PAGE