Does it matter if animals are conscious?

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Midgeley

Conclusion E.xx The absence of consciousness in certain kinds of animals renders it impossible for us to form emotionally symbiotic relationships (friendships) with them.

Case study - fish welfare

Sensitive and easily applied welfare indicators for fish

Source: FSBI. 2002. Fish Welfare. Briefing Paper No. 2, Fisheries Society of the British Isles, Granta Information Systems, Cambridge, UK.

Changes in colour: Stress-induced changes in skin or eye colour (with a complex hormonal background) have been reported in a number of fish species, including ornamental species (Etscheidt 1992), and so could be a sign of exposure to adverse events. Eye colour as an index of social stress/subordinate status in salmonids provides an example.

Changes in ventilation rate: A high oxygen demand is reflected by rapid irrigation of the gills. The rate of opercular beats is therefore increased by stress and can be counted, automatically or by eye. This, together with a visual assessment of gill status, is used as a sign of incipient problems in ornamental fish (Etscheidt 1992) and to monitor exposure to pollutants in salmonid fish.

Changes in swimming and other behaviour patterns: Fish may respond to unfavourable conditions by adopting different speeds of swimming and by using of different regions of a tank or cage (Morton 1990, Etscheidt 1992, Juell1995). Abnormal swimming has been used as a sign of poor welfare in farmed fish (Holm et al. 1998). Known behavioural responses to adverse events and conditions are potential signs of both general and specific trouble (Morton1990). These include excessive activity or immobility (Etscheidt 1992), body positions that protect injured fins, escapeattempts in confined conditions and chafing movements to dislodge ecto-parasites (Furevik et al.1993).

Reduced food intake: Notwithstanding that there are many reasons why a fish might not eat, the fact that feeding is suppressed by acute and chronic stress means that loss of appetite is potentially a sign of impaired welfare.

Slow growth: Notwithstanding that growth rates in fish are flexible and naturally variable, sustained reductions in growth may be indicative of chronic stress. Thus where fish are regularly weighed or where size can be assessed by eye (or by underwater camera) slow growth can be used as a possible sign of trouble.

Loss of condition: Fish change shape and/or lose weight for many reasons, but because reduced feeding and mobilisation of reserves are secondary stress responses, where fish are regularly weighed and measured, or where body shape can be assessed by eye (for example by the visibility of the vertebrae, Escheidt 1992) loss of condition can be used as a possible sign of trouble.

Morphological abnormalities: Because adverse conditions can interfere with normal development, the occurrence of morphological abnormalities can be used as an indicator of poor larval rearing conditions (Boglione et al. 2001).

Injury: Injury may be a direct consequence of an adverse event, in which case, the presence of such injuries is a sign of poor welfare. For example, dorsal fin injury in salmonids is often caused by attacks from conspecifics (Turnbull et al. 1998) and scales that are dislodged rather than lying flat are a sign of poor welfare in ornamental fish (Etscheidt 1992). In addition, because immune responses can be suppressed by cortisol, slow recovery from injury (or a high incidence of injury) may be a sign of generally poor conditions. However, fin erosion has multiple causes and these are not fully understood.

Disease states: Since the causes of most aquatic diseases are complex and dependent on environmental conditions, a diseased state can indicate an underlying problem with the environment or management. Increased incidence of disease in any population of fish should be treated as a warning that there may be other underlying problems. However, interpreting the welfare implications of an observed disease requires a detailed understanding of the natural history of the disease and in some cases diseases are not sufficiently well understood to interpret their implications for welfare.

Reduced reproductive performance: For many farmed species, reproduction is prevented or avoided in growing stock. Where this is not the case, for example, in brood stock or where ornamental fish are concerned, because chronic stress impairs reproductive function, failure of adult fish to breed or to display normal patterns of reproductive behaviour.

Overview of current scientific understanding of the impact of common practice in aquaculture, angling and the keeping of ornamental fish, with a few representative examples

Source: FSBI. 2002. Fish Welfare. Briefing Paper No. 2, Fisheries Society of the British Isles, Granta Information Systems, Cambridge, UK.

AQUACULTURE: SOME DEMONSTRATED EFFECTS ON WELFARE

Transportation Certain kinds of transportation induce physiological stress responses and a prolonged recovery period may be necessary (Bandeen & Leatherland 1997, Barton 2000, Rouger et al. 1998, Iversen et al. 1998, Sandodden et al. 2001).

Handling/netting Physical disturbance evokes physiological stress responses in many species of farmed fish (reviewed by Pickering 1998) and reduces disease resistance (Stangeland et al. 1996).

Confinement and short-term crowding Physical confinement in otherwise favourable conditions increases cortisol and glucose levels and alters macrophage activity in various species (Garci-Garbi et al. 1998). Carp show a mild, physiological stress response to crowding that declined as the fish adapted, but crowded fish are more sensitive to an additional acute stressor (confinement in a net; Ruane et al. 2002). Crowding during grading increases cortisol levels for up to 48h (Barnett & Pankhurst 1998).

Inappropriate densities High densities impair welfare in some species (trout, salmon: Ewing & Ewing 1995, bass: Vazzana 2002, red porgy: Rotllani & Tori 1997), but enhance it in others (catfish and Arctic charr, Jorgensen et al. 1993). Halibut suffer less injury at high densities (Greaves 2002) but show more abnormal swimming (Kristiansen & Juell 2002). The relationship between welfare and density may be non-linear; low densities may harm rainbow trout, in salmon negative effects start to appear at a critical density and density interacts with other factors such as disturbance or water quality (Ewing & Ewing 1995, Bell 2002, Scott et al. 2001).

Enforced social contact Aggression can cause injury in farmed fish, especially when competition for food is strong (Greaves & Tuene 2001). Subordinate fish can be prevented from feeding (Cubitt 2002), may grow poorly and are more vulnerable to disease (reviewed by Wedermeyer 1996).

Water quality deterioration Many adverse effects of poor water quality have been described, with different variables interacting, e.g. undisturbed salmonids use c. 300 mg of oxygen per kg of fish per hour and this can double if the fish are disturbed. For such species, access to aerated water is essential for health (Wedermeyer 1996). Immunoglobulin levels fall in sea bass held at low oxygen levels (Scapigliati et al.1999). Heavy metals cause extensive gill damage in acidic water but are non-toxic in hard, alkaline water (see Wedermeyer 1996).

Altered light regimes Atlantic salmon avoid bright surface lights, except when feeding (Fernoe et al.1995). Continuous light increases growth in several species (e.g. cod: Puvanendran & Brown 2002).

Food deprivation Dorsal fin erosion increases during fasting in steelhead trout (Winfree et al.1998). Plasma glucose increase in Atlantic salmon after 7 days without food, but other welfare indices are unaffected (Bell 2002). Atlantic salmon deprived of food for longer periods (up to 86 days) lose weight and condition, stabilising after 30 days (Einen et al. 1998). Farmed Atlantic salmon swim slower and fight less during feeding bouts when fed on demand (Andrews et al. 2002).

Disease treatment Therapeutic treatments themselves may be stressful to fish (e.g. Griffin et al. 1999, 2002, Thorburn et al. 2001, Yildiz & Pulatsu, 1999).

Unavoidable contact with predators Brief exposure to a predator causes increased cortisol levels and respiration rate and suppressed feeding (eg Metcalfe et al. 1987). Mortality and injury due to attacks by birds and seals can be high among farmed fish (eg Carss 1993).

Slaughter All slaughter methods are stressful, but some are lees so than others (Robb et al.2000). Small, warm water fish such as sea bass killed by chilling in ice water had lower plasma glucose and lactate levels and showed less marked behavioural responses than those killed by other methods, in particular asphyxia (Poli et al. 2002, Skjervold et al. 2001). Electostunning may be less harmful for larger fish such as trout.

ANGLING: SOME DEMONSTRATED EFFECTS ON WELFARE

Capture - hooking Injury and mortality following hooking is common, primarily in deep-hooked fish (Dubois et al.1994; Hulbert & Engstrom-Heg 1980, Muonehke & Childress 1994).

Capture - playing / landing Capture of fish by rod and line elicits a stress response of short duration (Gustaveson et al. 1991, Pankhurst & Dedual 1994, Pottinger 1998). Estradiol levels are suppressed in rainbow trout within 24h of capture by rod and line (Pankhurst & Dedual 1994).

Capture - handling Exposure of exercised fish to air can have severe metabolic effects (lactate increase and altered acid-base balance), especially in larger fish (Ferguson et al. 1993). Capture and handling suppress reproductive function in brown trout (Melotti et al. 1992).

Retention / constraint / release Retention of fish post-capture in either keepnets or stringers induces physiological stress responses, but recovery following release can be rapid (Pottinger 1998, Sobchuk & Dawson 1988). Hooking and handling for release can increase scale damage by 16% (Broadhurst & Barker 2000), possibly making released fish liable to infection. Abnormal behaviour can occur following release after a stressful event (Mesa & Schreck 1989, Olla & Davis 1989).

KEEPING ORNAMENTAL FISH - SOME DEMONSTRATED EFFECTS ON WELFARE

Capture. Exposure to Poisons. Marine tropical fish captured by sodium cyanide suffer very high mortality for several weeks after capture (Hignette 1984). Clove oil is a better alternative (Erdmann 2002).

Transportation Estimates for mortality during capture of ornamental fish from South America range from 5 to 10% but may be as high as 30%. A further 5 to 10% mortality is estimated to occur during transportation and at the holding facilities (Ferraz de Olivera 1995). During the acclimation period following importation mortalities can be up to 30% (FitzGibbon 1993). However, in all these aspects of the ornamental fish trade there is a great deal of variability. The Ornamental Fish Trade Association has regulations to improve all aspects of capture and transport of fish (www.aquariumcouncil.org).

After purchase, constraint in a confined space See above, under aquaculture.

Handling See above, under aquaculture.

Inappropriate densities/species combinations Lack of appropriate social environment (wrong species or inappropriate numbers) is an important cause of poor health in ornamental fish (Etscheidt 1995).

Poor water quality 81% of ornamental fish are held outside the optimal pH range, 36% at inappropriate temperatures (Etscheidt & Manz 1992). Poor water quality is the commonest cause of mortality in ornamental fish (Schunck 1980).

Deprivation of social contact Angelfish transferred singly to a new tank take longer to resume feeding than those transferred in groups of 3 or 5 (Gomez-Laplaza & Morgan 1993).

Inappropriate feeding regimes Inappropriate range and types of food can cause poor health in ornamental fish (Etscheidt 1995). Inappropriate feeding is not usually a direct cause of mortality in ornamental fish, but can be a contributory factor (Schunck 1980).

Unavoidable contact with a predator In 19% ornamental tanks prey were housed in small tanks in direct contact with predators (Escheidt & Manz 1992, Foggitt 1997). See above under aquaculture.

Disease treatment See above under aquaculture.

Conclusion E.xx There are three ways in which interests may be imputed to animals:

1. All animals, like other living things, have an interest in those things that are conducive to their biological health. These biological interests can be harmed by stressful or noxious events in their environment.
2. Animals with "minimal minds" (of the sort described in chapter two) lack conscious feelings but possess unconscious beliefs, desires and intentions. These animals can be said to take an interest in whatever they pursue. These animals may (i) have a biological interest in things in which they take no interest, and may also (ii) take an interest in things that are harmful to their biological health, which they have no interest (biologically speaking) in realising.
3. Animals with phenomenally conscious feelings in addition to beliefs, desires and intentions, may be said to feel interested in whatever they pursue. As well as being subject to conflicts between their biological interests and the things in which they take an interest, they may also be induced (under special circumstances) to take an interest in things in which they feel no interest (but not vice versa).

Berridge

Carruthers

Conclusion E.xx Most animals are not phenomenally conscious, but possess minimal minds. Since the absence of conscious feelings in these animals in no way precludes them from taking an interest in things they enjoy, and trying to avoid things they do not want, the absence of conscious feelings in animals is of little ethical consequence.

Conclusion E.xx Animals lacking even minimal minds still have biological interests of their own, like other living things. These interests can be harmed by stressful or noxious events in their environment. We have the same obligations towards those animals as we have towards other living things. (I discuss these obligations in chapters 5 and 6.)

Transportation	Certain kinds of transportation induce physiological stress responses and a prolonged recovery period may be necessary (Bandeen & Leatherland 1997, Barton 2000, Rouger et al. 1998, Iversen et al. 1998, Sandodden et al. 2001).
Handling/netting	Physical disturbance evokes physiological stress responses in many species of farmed fish (reviewed by Pickering 1998) and reduces disease resistance (Stangeland et al. 1996).
Confinement and short-term crowding	Physical confinement in otherwise favourable conditions increases cortisol and glucose levels and alters macrophage activity in various species (Garci-Garbi et al. 1998). Carp show a mild, physiological stress response to crowding that declined as the fish adapted, but crowded fish are more sensitive to an additional acute stressor (confinement in a net; Ruane et al. 2002). Crowding during grading increases cortisol levels for up to 48h (Barnett & Pankhurst 1998).
Inappropriate densities	High densities impair welfare in some species (trout, salmon: Ewing & Ewing 1995, bass: Vazzana 2002, red porgy: Rotllani & Tori 1997), but enhance it in others (catfish and Arctic charr, Jorgensen et al. 1993). Halibut suffer less injury at high densities (Greaves 2002) but show more abnormal swimming (Kristiansen & Juell 2002). The relationship between welfare and density may be non-linear; low densities may harm rainbow trout, in salmon negative effects start to appear at a critical density and density interacts with other factors such as disturbance or water quality (Ewing & Ewing 1995, Bell 2002, Scott et al. 2001).
Enforced social contact	Aggression can cause injury in farmed fish, especially when competition for food is strong (Greaves & Tuene 2001). Subordinate fish can be prevented from feeding (Cubitt 2002), may grow poorly and are more vulnerable to disease (reviewed by Wedermeyer 1996).
Water quality deterioration	Many adverse effects of poor water quality have been described, with different variables interacting, e.g. undisturbed salmonids use c. 300 mg of oxygen per kg of fish per hour and this can double if the fish are disturbed. For such species, access to aerated water is essential for health (Wedermeyer 1996). Immunoglobulin levels fall in sea bass held at low oxygen levels (Scapigliati et al.1999). Heavy metals cause extensive gill damage in acidic water but are non-toxic in hard, alkaline water (see Wedermeyer 1996).
Altered light regimes	Atlantic salmon avoid bright surface lights, except when feeding (Fernoe et al.1995). Continuous light increases growth in several species (e.g. cod: Puvanendran & Brown 2002).
Food deprivation	Dorsal fin erosion increases during fasting in steelhead trout (Winfree et al.1998). Plasma glucose increase in Atlantic salmon after 7 days without food, but other welfare indices are unaffected (Bell 2002). Atlantic salmon deprived of food for longer periods (up to 86 days) lose weight and condition, stabilising after 30 days (Einen et al. 1998). Farmed Atlantic salmon swim slower and fight less during feeding bouts when fed on demand (Andrews et al. 2002).
Disease treatment	Therapeutic treatments themselves may be stressful to fish (e.g. Griffin et al. 1999, 2002, Thorburn et al. 2001, Yildiz & Pulatsu, 1999).
Unavoidable contact with predators	Brief exposure to a predator causes increased cortisol levels and respiration rate and suppressed feeding (eg Metcalfe et al. 1987). Mortality and injury due to attacks by birds and seals can be high among farmed fish (eg Carss 1993).
Slaughter	All slaughter methods are stressful, but some are lees so than others (Robb et al.2000). Small, warm water fish such as sea bass killed by chilling in ice water had lower plasma glucose and lactate levels and showed less marked behavioural responses than those killed by other methods, in particular asphyxia (Poli et al. 2002, Skjervold et al. 2001). Electostunning may be less harmful for larger fish such as trout.

Capture - hooking	Injury and mortality following hooking is common, primarily in deep-hooked fish (Dubois et al.1994; Hulbert & Engstrom-Heg 1980, Muonehke & Childress 1994).
Capture - playing / landing	Capture of fish by rod and line elicits a stress response of short duration (Gustaveson et al. 1991, Pankhurst & Dedual 1994, Pottinger 1998). Estradiol levels are suppressed in rainbow trout within 24h of capture by rod and line (Pankhurst & Dedual 1994).
Capture - handling	Exposure of exercised fish to air can have severe metabolic effects (lactate increase and altered acid-base balance), especially in larger fish (Ferguson et al. 1993). Capture and handling suppress reproductive function in brown trout (Melotti et al. 1992).
Retention / constraint / release	Retention of fish post-capture in either keepnets or stringers induces physiological stress responses, but recovery following release can be rapid (Pottinger 1998, Sobchuk & Dawson 1988). Hooking and handling for release can increase scale damage by 16% (Broadhurst & Barker 2000), possibly making released fish liable to infection. Abnormal behaviour can occur following release after a stressful event (Mesa & Schreck 1989, Olla & Davis 1989).

Capture. Exposure to Poisons.	Marine tropical fish captured by sodium cyanide suffer very high mortality for several weeks after capture (Hignette 1984). Clove oil is a better alternative (Erdmann 2002).
Transportation	Estimates for mortality during capture of ornamental fish from South America range from 5 to 10% but may be as high as 30%. A further 5 to 10% mortality is estimated to occur during transportation and at the holding facilities (Ferraz de Olivera 1995). During the acclimation period following importation mortalities can be up to 30% (FitzGibbon 1993). However, in all these aspects of the ornamental fish trade there is a great deal of variability. The Ornamental Fish Trade Association has regulations to improve all aspects of capture and transport of fish (www.aquariumcouncil.org).
After purchase, constraint in a confined space	See above, under aquaculture.
Handling	See above, under aquaculture.
Inappropriate densities/species combinations	Lack of appropriate social environment (wrong species or inappropriate numbers) is an important cause of poor health in ornamental fish (Etscheidt 1995).
Poor water quality	81% of ornamental fish are held outside the optimal pH range, 36% at inappropriate temperatures (Etscheidt & Manz 1992). Poor water quality is the commonest cause of mortality in ornamental fish (Schunck 1980).
Deprivation of social contact	Angelfish transferred singly to a new tank take longer to resume feeding than those transferred in groups of 3 or 5 (Gomez-Laplaza & Morgan 1993).
Inappropriate feeding regimes	Inappropriate range and types of food can cause poor health in ornamental fish (Etscheidt 1995). Inappropriate feeding is not usually a direct cause of mortality in ornamental fish, but can be a contributory factor (Schunck 1980).
Unavoidable contact with a predator	In 19% ornamental tanks prey were housed in small tanks in direct contact with predators (Escheidt & Manz 1992, Foggitt 1997). See above under aquaculture.
Disease treatment	See above under aquaculture.