Animal welfare

A four-week-old puppy, found alongside a road after flooding in West Virginia, is fed at an Emergency Animal Rescue Service shelter in the Twin Falls State Park.

Animal welfare is the well-being of animals. The standards of "good" animal welfare vary considerably between different contexts. These standards are under constant review and are debated, created and revised by animal welfare groups, legislators and academics worldwide. Animal welfare science uses measures such as longevity, disease, immunosuppression, behavior, physiology, and reproduction, although there is debate about which of these indicators provide the best information.

Concern for animal welfare is often based on the belief that non-human animals are sentient and that consideration should be given to their well-being or suffering, especially when they are under the care of humans. These concerns can include how animals are slaughtered for food, how they are used in scientific research, how they are kept (as pets, in zoos, farms, circuses, etc.), and how human activities affect the welfare and survival of a wild species.

Animal welfare was a concern of some ancient civilizations but began to take a larger place in Western public policy in 19th-century Britain. Today it is a significant focus of interest in science, ethics, and animal welfare organizations.

There are two forms of criticism of the concept of animal welfare, coming from diametrically opposite positions. One view, dating back centuries, asserts that animals are not consciously aware and hence are unable to experience poor (or good) welfare. The other view is based on the animal rights position that animals should not be regarded as property and any use of animals by humans is unacceptable. Accordingly, some animal rights proponents argue that the perception of better animal welfare facilitates continued and increased exploitation of animals. Some authorities therefore treat animal welfare and animal rights as two opposing positions. Others see the increasing concern for animal welfare as incremental steps towards animal rights. The most widely held position in the western world is a mid-way utilitarian point-of-view; the position that it is morally acceptable for humans to use non-human animals, provided that adverse effects on animal welfare are minimized as much as possible.

Approaches and definitions

There are many different approaches to describing and defining animal welfare.

Conditions provided by humans

Providing good animal welfare is sometimes defined by a list of positive conditions which should be provided to the animal. This approach is taken by the Five Freedoms and the three principles of Professor John Webster.

The Five Freedoms are:

• Freedom from thirst and hunger – by ready access to fresh water and a diet to maintain full health and vigour
• Freedom from discomfort – by providing an appropriate environment including shelter and a comfortable resting area
• Freedom from pain, injury, and disease – by prevention or rapid diagnosis and treatment
• Freedom to express most normal behavior – by providing sufficient space, proper facilities, and company of the animal's own kind
• Freedom from fear and distress – by ensuring conditions and treatment which avoid mental suffering

John Webster defines animal welfare by advocating three positive conditions: Living a natural life, being fit and healthy, and being happy.

Production by animals

In the past, many have seen farm animal welfare chiefly in terms of whether the animal is producing well. The argument is that an animal in poor welfare would not be producing well, however, many farmed animals will remain highly productive despite being in conditions where good welfare is almost certainly compromised, e.g. layer hens in battery cages.

Feelings of animals

Ian Duncan focus more on the feelings of the animal in his 1996 book. His approach indicated the belief that animals should be considered as sentient beings. Duncan wrote, "Animal welfare is to do with the feelings experienced by animals: the absence of strong negative feelings, usually called suffering, and (probably) the presence of positive feelings, usually called pleasure. In any assessment of welfare, it is these feelings that should be assessed."

Yew-Kwang Ng defines animal welfare in terms of welfare economics: "Welfare biology is the study of living things and their environment with respect to their welfare (defined as net happiness, or enjoyment minus suffering). Despite difficulties of ascertaining and measuring welfare and relevancy to normative issues, welfare biology is a positive science."

Dictionary definition

In the Saunders Comprehensive Veterinary Dictionary, animal welfare is defined as "the avoidance of abuse and exploitation of animals by humans by maintaining appropriate standards of accommodation, feeding and general care, the prevention and treatment of disease and the assurance of freedom from harassment, and unnecessary discomfort and pain."

Veterinary profession

The American Veterinary Medical Association (AVMA) has defined animal welfare as: "An animal is in a good state of welfare if (as indicated by scientific evidence) it is healthy, comfortable, well nourished, safe, able to express innate behavior, and if it is not suffering from unpleasant states such as pain, fear, and distress." They have offered the following eight principles for developing and evaluating animal welfare policies.

• The responsible use of animals for human purposes, such as companionship, food, fiber, recreation, work, education, exhibition, and research conducted for the benefit of both humans and animals, is consistent with the Veterinarian's Oath.
• Decisions regarding animal care, use, and welfare shall be made by balancing scientific knowledge and professional judgment with consideration of ethical and societal values.
• Animals must be provided water, food, proper handling, health care, and an environment appropriate to their care and use, with thoughtful consideration for their species-typical biology and behavior.
• Animals should be cared for in ways that minimize fear, pain, stress, and suffering.
• Procedures related to animal housing, management, care, and use should be continuously evaluated, and when indicated, refined or replaced.
• Conservation and management of animal populations should be humane, socially responsible, and scientifically prudent.
• Animals shall be treated with respect and dignity throughout their lives and, when necessary, provided a humane death.
• The veterinary profession shall continually strive to improve animal health and welfare through scientific research, education, collaboration, advocacy, and the development of legislation and regulations.

Environment

Terrestrial Animal Health Code of World Organisation for Animal Health defines animal welfare as "how an animal is coping with the conditions in which it lives. An animal is in a good state of welfare if (as indicated by scientific evidence) it is healthy, comfortable, well nourished, safe, able to express innate behaviour, and if it is not suffering from unpleasant states such as pain, fear, and distress. Good animal welfare requires disease prevention and veterinary treatment, appropriate shelter, management, nutrition, humane handling and humane slaughter/killing. Animal welfare refers to the state of the animal; the treatment that an animal receives is covered by other terms such as animal care, animal husbandry, and humane treatment."

Coping

Professor Donald Broom defines the welfare of an animal as "Its state as regards its attempts to cope with its environment. This state includes how much it is having to do to cope, the extent to which it is succeeding in or failing to cope, and its associated feelings." He states that "welfare will vary over a continuum from very good to very poor and studies of welfare will be most effective if a wide range of measures is used." John Webster criticized this definition for making "no attempt to say what constitutes good or bad welfare."

Attitudes

Animal welfare often refers to a utilitarian attitude towards the well-being of nonhuman animals. It believes the animals can be exploited if the animal suffering and the costs of use is less than the benefits to humans. This attitude is also known simply as welfarism.

An example of welfarist thought is Hugh Fearnley-Whittingstall's meat manifesto. Point three of eight is:

Think about the animals that the meat you eat comes from. Are you at all concerned about how they have been treated? Have they lived well? Have they been fed on safe, appropriate foods? Have they been cared for by someone who respects them and enjoys contact with them? Would you like to be sure of that? Perhaps it's time to find out a bit more about where the meat you eat comes from. Or to buy from a source that reassures you about these points.

Robert Garner describes the welfarist position as the most widely held in modern society. He states that one of the best attempts to clarify this position is given by Robert Nozick:

Consider the following (too minimal) position about the treatment of animals. So that we can easily refer to it, let us label this position "utilitarianism for animals, Kantianism for people." It says: (1) maximize the total happiness of all living beings; (2) place stringent side constraints on what one may do to human beings. Human beings may not be used or sacrificed for the benefit of others; animals may be used or sacrificed for the benefit of other people or animals only if those benefits are greater than the loss inflicted.

Welfarism is often contrasted with the animal rights and animal liberation positions, which hold that animals should not be used by humans and should not be regarded as human property. However, it has been argued that both welfarism and animal liberation only make sense if it is assumed that animals have "subjective welfare."

New welfarism

New welfarism was coined by Gary L. Francione in 1996. It is a view that the best way to prevent animal suffering is to abolish the causes of animal suffering, but advancing animal welfare is a goal to pursue in the short term. Thus, for instance, new welfarists want to phase out fur farms and animal experiments but in the short-term they try to improve conditions for the animals in these systems, so they lobby to make cages less constrictive and to reduce the numbers of animals used in laboratories.

There is some evidence to suggest that empathy is an inherited trait (genetic). Multiple studies have found women have greater concern for animals than men, possibly the result of it being an evolutionarily beneficial trait in societies where women take care of domesticated animals while men hunt.

Laws punishing cruelty to animals tend to not just be based on welfare concerns but the belief that such behavior has repercussions toward the treatment of other humans by the animal abusers. Another argument against animal cruelty is based on aesthetics. Within the context of animal research, many scientific organisations believe that improved animal welfare will provide improved scientific outcomes. If an animal in a laboratory is suffering stress or pain it could negatively affect the results of the research.

Increased affluence in many regions for the past few decades afforded consumers the disposable income to purchase products from high welfare systems. The adaptation of more economically efficient farming systems in these regions were at the expense of animal welfare and to the financial benefit of consumers, both of which were factors in driving the demand for higher welfare for farm animals. A 2006 survey concluded that a majority (63%) of EU citizens "show some willingness to change their usual place of shopping in order to be able to purchase more animal welfare-friendly products."

Interest in animal welfare continues to grow, with increasing attention being paid to it by the media, governmental and non-governmental organizations. The volume of scientific research on animal welfare has also increased significantly in some countries.

History, principles, practice

File:Knut Briefmarke 2008.jpg

By the 21st century, promoting the interests of animals was mainstream and widespread. This German stamp uses the polar bear Knut to advocate for environmental responsibility.

Systematic concern for the well-being of other animals probably arose in the Indus Valley Civilization as religious ancestors were believed to return in animal form; therefore animals must be treated with respect. This belief is exemplified in the existing religion, Jainism, and in varieties of other Indian religions. Other religions, especially those with roots in the Abrahamic religions, treat animals as the property of their owners, codifying rules for their care and slaughter intended to limit the distress, pain, and fear animals experience under human control.

Early legislation which formed the impetus for assessing animal welfare and the subsequent development of animal welfare science include the Ireland Parliament (Thomas Wentworth) "An Act against Plowing by the Tayle, and pulling the Wooll off living Sheep", 1635, and the Massachusetts Colony (Nathaniel Ward) "Off the Bruite Creatures" Liberty 92 and 93 in the "Massachusetts Body of Liberties" of 1641.

Since 1822, when British MP Richard Martin brought the "Cruel Treatment of Cattle Act 1822" through Parliament offering protection from cruelty to cattle, horses, and sheep, the welfare approach has had human morality and humane behaviour as its central concerns. Martin was among the founders of the world's first animal welfare organization, the Society for the Prevention of Cruelty to Animals, or SPCA, in 1824. In 1840, Queen Victoria gave the society her blessing, and it became the RSPCA. The society used members' donations to employ a growing network of inspectors, whose job was to identify abusers, gather evidence, and report them to the authorities.

One of the first national laws to protect animals was the UK "Cruelty to Animals Act 1835" followed by the "Protection of Animals Act 1911". In the US it was many years until there was a National law to protect animals - the "Animal Welfare Act of 1966" - although there were a number of states that passed anti-cruelty laws between 1828 and 1898. In India, animals are protected by the "Prevention of Cruelty to Animals Act, 1960".

Significant progress in animal welfare did not take place until the late 20th century. In 1965, the UK government commissioned an investigation—led by Professor Roger Brambell—into the welfare of intensively farmed animals, partly in response to concerns raised in Ruth Harrison's 1964 book, Animal Machines. On the basis of Professor Brambell's report, the UK government set up the Farm Animal Welfare Advisory Committee in 1967, which became the Farm Animal Welfare Council in 1979. The committee's first guidelines recommended that animals require the freedoms to "stand up, lie down, turn around, groom themselves and stretch their limbs." The guidelines have since been elaborated upon to become known as the Five Freedoms.

In the UK, the "Animal Welfare Act 2006" consolidated many different forms of animal welfare legislation.

A number of animal welfare organisations are campaigning to achieve a Universal Declaration on Animal Welfare (UDAW) at the United Nations. In principle, the Universal Declaration would call on the United Nations to recognise animals as sentient beings, capable of experiencing pain and suffering, and to recognise that animal welfare is an issue of importance as part of the social development of nations worldwide. The campaign to achieve the UDAW is being co-ordinated by the World Society for the Protection of Animals, with a core working group including Compassion in World Farming, the RSPCA, and the Humane Society International (the international branch of HSUS).

Animal welfare science

Main article: Animal welfare science

Animal welfare science is an emerging field that seeks to answer questions raised by the keeping and use of animals, such as whether hens are frustrated when confined in cages, whether the psychological well-being of animals in laboratories can be maintained, and whether zoo animals are stressed by the transport required for international conservation.

Farm animals

The welfare of egg laying hens in battery cages (above) can be compared with the welfare of free range hens (below) which are given access to the outdoors.

A major concern for the welfare of farm animals is factory farming in which large numbers of animals are reared in confinement at high stocking densities. Issues include the limited opportunities for natural behaviors, for example, in battery cages, veal and gestation crates, instead producing abnormal behaviors such as tail-biting, cannibalism, and feather pecking, and routine invasive procedures such as beak trimming, castration, and ear notching. More extensive methods of farming, e.g. free range, can also raise welfare concerns such as the mulesing of sheep, predation of stock by wild animals, and biosecurity.

Farm animals are artificially selected for production parameters which sometimes impinge on the animals' welfare. For example, broiler chickens are bred to be very large to produce the greatest quantity of meat per animal. Broilers bred for fast growth have a high incidence of leg deformities because the large breast muscles cause distortions of the developing legs and pelvis, and the birds cannot support their increased body weight. As a consequence, they frequently become lame or suffer from broken legs. The increased bodyweight also puts a strain on their hearts and lungs, and ascites often develops. In the UK alone, up to 20 million broilers each year die from the stress of catching and transport before reaching the slaughterhouse.

Another concern about the welfare of farm animals is the method of slaughter, especially ritual slaughter. While the killing of animals need not necessarily involve suffering, the general public considers that killing an animal reduces its welfare. This leads to further concerns about premature slaughtering such as chick culling by the laying hen industry, in which males are slaughtered immediately after hatching because they are superfluous; this policy occurs in other farm animal industries such as the production of goat and cattle milk, raising the same concerns.

United States laws

In the United States, a federal law called the Humane Slaughter Act was designed to decrease suffering of livestock during slaughter.

The Georgia Animal Protection Act of 1986 was a state law enacted in response to the inhumane treatment of companion animals by a pet store chain in Atlanta. The Act provided for the licensing and regulation of pet shops, stables, kennels, and animal shelters, and established, for the first time, minimum standards of care. Additional provisions, called the Humane Euthanasia Act, were added in 1990, and then further expanded and strengthened with the Animal Protection Act of 2000.

In 2002, voters passed (by a margin of 55% for and 45% against) Amendment 10 to the Florida Constitution banning the confinement of pregnant pigs in gestation crates. In 2006, Arizona voters passed Proposition 204 with 62% support; the legislation prohibits the confinement of calves in veal crates and breeding sows in gestation crates. In 2007, the Governor of Oregon signed legislation prohibiting the confinement of pigs in gestation crates and in 2008, the Governor of Colorado signed legislation that phased out both gestation crates and veal crates. Also during 2008, California passed Proposition 2, known as the "Prevention of Farm Animal Cruelty Act", which orders new space requirements for farm animals starting in 2015.

European Union laws

European Union legislation regarding farm animal welfare is regularly re-drafted according to science-based evidence and cultural views. For example, in 2009, legislation was passed which aimed to reduce animal suffering during slaughter and on January 1, 2012, the European Union Council Directive 1999/74/EC came into act, which means that conventional battery cages for laying hens are now banned across the Union.

Laboratory animals

See also: Animal testing

United States laws

The use of animals in laboratories remains controversial. Animal welfare advocates push for enforced standards to ensure the health and safety of those animals used for tests.

In the US, every institution that uses vertebrate animals for federally funded laboratory research must have an Institutional Animal Care and Use Committee (IACUC). Each local IACUC reviews research protocols and conducts evaluations of the institution's animal care and use which includes the results of inspections of facilities that are required by law. The IACUC committee must assess the steps taken to "enhance animal well-being" before research can take place. This includes research on farm animals. According to the National Institutes of Health Office of Laboratory Animal Welfare, researchers must try to minimize distress in animals whenever possible: "Animals used in research and testing may experience pain from induced diseases, procedures, and toxicity. The Public Health Service (PHS) Policy and Animal Welfare Regulations (AWRs) state that procedures that cause more than momentary or slight pain or distress should be performed with appropriate sedation, analgesia, or anesthesia. However, research and testing studies sometimes involve pain that cannot be relieved with such agents because they would interfere with the scientific objectives of the study. Accordingly, federal regulations require that IACUCs determine that discomfort to animals will be limited to that which is unavoidable for the conduct of scientifically valuable research, and that unrelieved pain and distress will only continue for the duration necessary to accomplish the scientific objectives. The PHS Policy and AWRs further state that animals that would otherwise suffer severe or chronic pain and distress that cannot be relieved should be painlessly killed at the end of the procedure, or if appropriate, during the procedure."

The National Research Council's Guide for the Care and Use of Laboratory Animals also serves as a guide to improve welfare for animals used in research in the US. The Federation of Animal Science Societies' Guide for the Care and Use of Agricultural Animals in Research and Teaching is a resource addressing welfare concerns in farm animal research. Laboratory animals in the US are also protected under the Animal Welfare Act. The United States Department of Agriculture Animal and Plant Health Inspection Service (APHIS) enforces the Animal Welfare Act. APHIS inspects animal research facilities regularly and reports are published online.

According to the U.S. Department of Agriculture (USDA), the total number of animals used in the U.S. in 2005 was almost 1.2 million, but this does not include rats, mice, and birds which are not covered by welfare legislation but make up approximately 90% of research animals.

United Kingdom laws

The Animal Welfare Act 2006 makes owners and keepers responsible for ensuring that the welfare needs of their animals are met. These include the need: for a suitable environment (place to live), for a suitable diet, to exhibit normal behaviour patterns, to be housed with, or apart from, other animals (if applicable), and to be protected from pain, injury, suffering and disease. Anyone who is cruel to an animal, or does not provide for its welfare needs, may be banned from owning animals, fined up to £20,000 and/or sent to prison.

In the UK, the welfare of research animals being used for "regulated procedures" was historically protected by the Animals (Scientific Procedures) Act 1986 (ASPA) which is administrated by the Home Office. The Act defines "regulated procedures" as animal experiments that could potentially cause "pain, suffering, distress or lasting harm" to "protected animals." Initially, "Protected animals" encompassed all living vertebrates other than humans, but in 1993, an amendment added a single invertebrate species, the common octopus. Primates, cats, dogs, and horses have additional protection over other vertebrates under the Act. Revised legislation came into force in January 2013. This has been expanded to protect "...all living vertebrates, other than man, and any living cephalopod. Fish and amphibia are protected once they can feed independently and cephalopods at the point when they hatch. Embryonic and foetal forms of mammals, birds and reptiles are protected during the last third of their gestation or incubation period." The definition of regulated procedures was also expanded: "A procedure is regulated if it is carried out on a protected animal and may cause that animal a level of pain, suffering, distress or lasting harm equivalent to, or higher than, that caused by inserting a hypodermic needle according to good veterinary practice." It also includes modifying the genes of a protected animal if this causes the animal pain, suffering, distress, or lasting harm. The ASPA also considers other issues such as animal sources, housing conditions, identification methods, and the humane killing of animals. This legislation is widely regarded as the strictest in the world. Those applying for a license must explain why such research cannot be done through non-animal methods. The project must also pass an ethical review panel which aims to decide if the potential benefits outweigh any suffering for the animals involved.

Criticisms

Animals as automatons

Renes Descartes argued that animals were not conscious and behaved as automatons.

At one time, many people denied that non-human animals could feel anything and believed that they were incapable of conscious thought, thus the concept of animal welfare was meaningless. For example, many Cartesians were of this opinion. René Descartes wrote that animals act "without consciousness", much like a machine. In addition, there are accounts of Descartes visiting slaughter houses to observe how animals died. Believing that the animals were devoid of sentience, Descartes thought the death throes of animals was akin to "taking apart a spring-driven clock." In the Discourse, published in 1637, Descartes wrote that the ability to reason and use language involves being able to respond in complex ways to all the "contingencies of life", something that animals "clearly cannot do." He argued from this that any sounds animals make do not constitute language, but are simply "automatic responses to external stimuli."

Animal rights

American philosopher Tom Regan has criticized the animal welfare movement for not going far enough to protect animals' interests.

Animal rights advocates, such as Gary L. Francione and Tom Regan, argue that the animal welfare position (advocating for the betterment of the condition of animals, but without abolishing animal use) is inconsistent in logic and ethically unacceptable. However, there are some animal rights groups, such as PETA, which support animal welfare measures in the short term to alleviate animal suffering until all animal use is ended. According to PETA's Ingrid Newkirk in an interview with Wikinews, there are two issues in animal welfare and animal rights. "If I only could have one thing, it would be to end suffering," said Newkirk. "If you could take things from animals and kill animals all day long without causing them suffering, then I would take it... Everybody should be able to agree that animals should not suffer if you kill them or steal from them by taking the fur off their backs or take their eggs, whatever. But you shouldn't put them through torture to do that."

Abolitionism holds that focusing on animal welfare not only fails to challenge animal suffering, but may actually prolong it by making the exercise of property rights over animals appear less unattractive. The abolitionists' objective is to secure a moral and legal paradigm shift, whereby animals are no longer regarded as property.

Animal welfare organizations

Global

The WSPA was founded in 1981 to fight animal cruelty.

World Organisation for Animal Health (OIE): The intergovernmental organisation responsible for improving animal health worldwide. The OIE has been established "for the purpose of projects of international public utility relating to the control of animal diseases, including those affecting humans and the promotion of animal welfare and animal production food safety."

World Society for the Protection of Animals (WSPA): Tackles animal cruelty across the globe. WSPA's objectives include helping people understand the critical importance of good animal welfare, encouraging nations to commit to animal-friendly practices, and building the scientific case for the better treatment of animals. They are global in a sense that they have consultative status at the Council of Europe and collaborate with national governments, the United Nations, the Food and Agriculture Organization and the World Organization for Animal Health.

Non-government organizations

Canadian Council on Animal Care: The national organization responsible for overseeing the care and use of animals involved in Canadian Science.

Canadian Federation of Humane Societies (CFHS): The only national organization representing human societies and SPCAs in Canada. They provide leadership on animal welfare issues and spread the message across Canada.

The Canadian Veterinary Medical Association: Brings in veterinary involvement to animal welfare. Their objective is to share this concern of animals with all members of the profession, with the general public, with government at all levels, and with other organizations such as the CFHS, which have similar concerns.

Compassion in World Farming: Founded over 40 years ago in 1967 by a British farmer who became horrified by the development of modern, intensive factory farming. "Today we campaign peacefully to end all cruel factory farming practices. We believe that the biggest cause of cruelty on the planet deserves a focused, specialised approach – so we only work on farm animal welfare."

The Movement for Compassionate Living: Exists to- "Promote simple vegan living and self-reliance as a remedy against the exploitation of humans, animals and the Earth. Promote the use of trees and vegan-organic farming to meet the needs of society for food and natural resources. Promote a land-based society where as much of our food and resources as possible are produced locally."

National Farm Animal Care Council: Their objectives are to facilitate collaboration among members with respect to farm animal care issues in Canada, to facilitate information sharing and communication, and to monitor trends and initiatives in both the domestic and international market place.

National Office of Animal Health: A British organisation that represents its members drawn from the animal medicines industry.

Ontario Society for the Prevention of Cruelty to Animals: A registered charity comprising over 50 communities.

Royal Society for the Prevention of Cruelty to Animals: A well-known animal welfare charity in England and Wales, founded in 1824.

See also

• Abandoned pets
• Animal consciousness
• Animal law
• Animal welfare science
• Animal worship
• Behavioral enrichment
• Blood sport
• Cruelty to animals
• Cambridge Declaration on Consciousness

• Eurogroup for Animals
• Feral cat
• Francis of Assisi
• Hunting
• Intrinsic value (animal ethics)
• List of abnormal behaviours in animals
• List of animal welfare groups
• List of animal welfare parties
• List of vegans
• Overpopulation in companion animals
• Overview of discretionary invasive procedures on animals

• Pain in animals
• Pain in invertebrates
• Poaching
• Puppy mills
• Whaling
• Women and animal advocacy

Organizations

• Canadian Federation of Humane Societies
• World Organisation for Animal Health

External links

• Animal Kill Counter
• Animal Welfare Science Centre
• Department for the Environment, Food and Rural Affairs page on animal welfare legislation
• Careers Helping Animals
• Chesley V. Morton v. Georgia Department of Agriculture and Tommy Irvin in his Official Capacity as Commissioner
• Farm Animal Welfare: Philosophical Aspects from the Encyclopedia of Animal Science
• Humane Education Past, Present, and Future from The State of the Animals II: 2003
• Dr. Temple Grandin's Web Page
• Huntingford FA, C Adams, VA Braithwaite, S Kadri, TG Pottinger, P Sandøe and JF Turnbull (2006) "Review paper: Current issues in fish welfare" Journal of fish biology, 68 (2): 332–372. doi:10.1111/j.0022-1112.2006.001046.x