08_Pain research improves welfare of fish.
Submitting InstitutionUniversity of Edinburgh
Unit of AssessmentBiological Sciences
Summary Impact TypePolitical
Research Subject Area(s)
Medical and Health Sciences: Neurosciences, Pharmacology and Pharmaceutical Sciences
Summary of the impact
Impact on society, culture and creativity: Public debate has been
stimulated and informed by the UoE research demonstrating that fish feel
Impact on policy, animal welfare, commerce and production: UK, EU
and RSPCA Animal Welfare policies and guidelines have been informed by the
research. Aquaculture has adopted welfare for fish with the use of humane
slaughter methods adopted in many farms.
Beneficiaries: Millions of farmed fish in the EU (including at
least 75,000 tonnes of salmon produced annually in Scotland); the
aquaculture industry; fish used in research; animal welfare organisations
and public awareness.
Significance and Reach: Public interest in the debate has been
worldwide; the impact on animal welfare practices is clearly evidenced in
Attribution: The Principal Investigator was Victoria Braithwaite,
Reader at School of Biological Sciences, University of Edinburgh. Mike
Gentle, Co-investigator, and Lynne Sneddon, PDRA, were at Roslin
Nociception is the detection of a noxious tissue-damaging stimulus and is
sometimes accompanied by a reflex response such as withdrawal. Pain
perception, as distinct from nociception, has been demonstrated in birds
and mammals but had not been systematically studied in lower vertebrates.
UoE research led by Victoria Braithwaite and Mike Gentle assessed whether
teleost (bony) fish possessed cutaneous nociceptors capable of detecting
noxious stimuli and whether their behaviour was sufficiently adversely
affected by the administration of a noxious stimulus to suggest
discomfort. Electrophysiological recordings from trigeminal nerves
identified polymodal nociceptors on the head of the fish with
physiological properties similar to those described in higher vertebrates.
These receptors responded to mechanical pressure, temperatures greater
than 40°C and 1% acetic acid. Administration of noxious substances to the
lips of the fish affected both its physiology and behaviour and resulted
in a significant increase in opercular beat rate and the time taken to
resume feeding, as well as anomalous behaviours. This study  provided
significant evidence of nociception in teleost fishes and demonstrated
that behaviour and physiology are affected over a prolonged period of
time, suggesting discomfort.
Further research  by Braithwaite, Sneddon and Gentle aimed to assess
fear responses to a novel object while experiencing a noxious event to
determine whether nociception or fear will dominate attention in rainbow
trout. The degree of neophobia to a novel object while experiencing
noxious stimulation, or a control treatment treated with a non-noxious
stimulus, and the effects of removing the nociceptive response by morphine
administration and examining the response to a novel object were studied.
Control animals displayed a classic fear response to the novel objects and
spent most of their time moving away from this stimulus, as well as
showing an increase in respiration rate when the novel object was
presented. In contrast, noxiously stimulated animals spent most of their
time in close proximity to the novel object and showed no additional
increase in respiration rate to novel object presentation. There was
evidence of a slight hypoalgesia in noxiously stimulated animals. The
responses to familiar objects demonstrated that by familiarizing the
animal with the object, fear was removed from the experiment. Both control
and noxiously treated animals responded in similar ways to a novel object
by spending the majority of their time in close proximity. Treatment with
morphine reduced effects of noxious stimulation and appears to be an
effective analgesic [2, 3]. After morphine administration, the
acid-injected animals showed a neophobic response to a novel object and
this was similar to the response of the control fish, with a similar
amount of time spent moving away from the object and an increase in
ventilation in response to the novel object. Morphine affected the fear
response because both groups approached the novel object more quickly than
the non-morphine controls. The results suggested that nociception captures
the animal's attention with only a relatively small amount of attention
directed at responding to the fear of the novel object, indicating that
fish do feel pain. This research provided the first conclusive evidence of
pain perception in teleost fish.
Key personnel, all at UoE on dates shown: Victoria Braithwaite, Principal
Investigator, School of Biological Sciences (1995-2007). Mike Gentle (UoE
Roslin Institute) was co-investigator and Lynne Sneddon was PDRA (UoE
2000-2002; work carried out at UoE in this period was published in 2003
after Sneddon had moved to Liverpool)
References to the research
3. Sneddon, L. U. (2003) The evidence for pain in fish: the use of
morphine as an analgesic. Applied Animal Behavior Science, 83,
Issue 2, pp153-162.
110 Scopus citations at 16/10/2013
Details of the impact
The UoE research indicating that fish can feel pain stimulated public
debate about sport angling and fishing for food, and contributed to
changes in animal welfare policies affecting research animals and farmed
Impact on society, culture and creativity: public debate
The research was widely reported at the time of publication in 2003 (e.g.
Braithwaite subsequently (2010) published a book based on this research: `Do
Fish Feel Pain?' [a], to positive reviews by both the
scientific and lay press.
`An accessible and compelling account...her book will make an
important contribution to the debate.' - Anne Magurran, Times
It is available in hardback and e-book format. Over 2,500 copies have
been sold worldwide during the REF impact census period.
The publication of Braithwaite's book gave rise to press attention and
debate world-wide. Peter Singer, Professor of Bioethics at Princeton
University, wrote the article `If fish could scream' which was
published by public debate forum Project Syndicate [b]. This was
reproduced globally in news media including the Guardian newspaper (http://www.theguardian.com/commentisfree/cif-
green/2010/sep/14/fish-forgotten-victims) and translated into at
least nine languages including Chinese and Russian. Numerous other
articles appeared in local and national press including an article
published on the `care2make a difference' website in Jan 2013 [c] which
had 1,777,951 unique visitors, 1828 of whom shared it on Facebook and it
attracted 699 comments. Other media interest included articles in
international media and publications such as Daily India (e.g. http://www.dailyindia.com/show/412730.php),
the online arm of the Philadelphia Enquirer in the USA (http://articles.philly.com/2011-11-07/news/30369892_1_fish-species-brains),
and a feature on Discovery news which was widely reproduced elsewhere [d].
Animal rights and welfare organisations have widely quoted the research
to support their campaigns. People for the Ethical Treatment of Animals
(PETA) is the largest animal rights organisation in the world, with more
than 3 million members and supporters. They quote the UoE research and
Braithwaite's book in their campaigns aimed at the general public and to
lobby angling communities world-wide on the ethics of fishing [e]. For
example they flew an aeroplane banner entitled `Fish feel pain - hooks
hurt' over the Milwaukee Brew City Salmon Tournament in 2010, campaigned
in Virginia in 2011, in Seattle (one of the biggest fishing cities in the
USA) in 2011 and in Pensacola in 2012. Fishcount is a UK-based website
which aims to increase understanding of fish sentience, raise awareness
and promote solutions to the suffering of fishes in commercial fishing and
also aims to increase awareness of the welfare issues in fish farming.
They refer to the UoE research and Braithwaite's book, throughout their
website and publications [f].
Impact on public policy debate, changes to guidelines, and animal
(i) Animals used in scientific procedures
A 2006 review by the UK Government Animal Procedures Committee (APC) of
Schedule 1 of the UK Animals (Scientific Procedures) Act 1986 noted that
there was a need for further consideration of techniques for the humane
killing of fish, arising from new understanding on fish pain and welfare [http://www.official-documents.gov.uk/document/hc0708/hc00/0041/0041.pdf].
The Housing and Husbandry subcommittee was tasked by APC to provide a
supplementary report on the humane killing of fish. Braithwaite and
Sneddon contributed expert advice based on their research papers [1,2,3]
that helped inform the APC Supplementary Review of Schedule 1 of the
`Animals (Scientific Procedures) Act 1986: Appropriate methods of humane
killing for fish' published in June 2009 [g, h]. This report also
references paper .
Advice from this supplementary Review was submitted to the Home Secretary
and contributed to guidance for the revised Schedule 1. It is the
understanding of the Review Chair that these recommendations were also
submitted onward to the European Commission. The European Directive
2010/63/EU on the protection of animals used for scientific purposes was
adopted on 22 September 2010 and was transposed to UK legislation, and
included directives for humane killing of fish. The revised Schedule 1 of
the Animals (Scientific Procedures) Act 1986 came into effect on 1st
(ii) Farmed fish
In 2008 the EU commissioned the European Food Safety Authority (EFSA) to
deliver a Scientific Opinion on welfare aspects of farmed fish [i]. This
Scientific Opinion was developed by EFSA's Animal Health and Welfare
(AHAW) panel and was adopted by EFSA on 29 January 2009. The report
extensively referenced the two 2003 papers [1, 2] in the discussion of
fish pain (Section 5) and concluded that `the balance of the evidence
indicates that some fish species have the capacity to experience pain' and
that `responses of fish, of some species and under certain situations,
suggest that they are able to experience fear'.
Aquaculture is the fastest growing form of farming with large facilities
producing an estimated 6,400-110,000 million fish per year globally.
Atlantic salmon is the most commonly farmed species in the UK, with
approximately 70 companies producing over 140,000 tonnes of farmed salmon
each year (RSPCA figures). 90% of this occurs in Scotland and it is
Scotland's largest export. The UK RSPCA published Welfare Standards for
farmed Atlantic salmon in October 2012 (http://www.rspca.org.uk/ImageLocator/LocateAsset?asset=document&assetId=1232731074670&
mode=prd). These state that `scientific evidence from behavioural,
physiological and anatomical studies shows that it is highly likely that
fish feel pain. It is essential that staff managing farmed fish are aware
of the importance of welfare as an integral part of production'. Over 60%
of Scottish farmed salmon producers have `Freedom Food' (the RSPCA's farm
assurance and food labelling scheme) accreditation and this is increasing.
One Scottish salmon farm manager quoted by the Freedom Food documentation
confirms the importance of the understanding that fish feel pain to this
approach to farming:
"Some people don't associate fish with pain and stress. But they feel
both, just like other sentient beings and it's really important to me
and all who work for me, that we rear them to high welfare standards."
In December 2012, over 100 million salmon were farmed in accordance with
the RSPCA's Freedom Food welfare guidelines. This improvement in fish
welfare originated in the 2003 UoE publication which contained the first
widely-reported demonstration that fish feel pain.
Sources to corroborate the impact
The Tiny URLs provide a link to archived web content, which should be
accessed if the original website content is no longer available.
a. Do Fish Feel Pain? by Victoria Braithwaite (978-0-19-955120-0),
published 25th March 2010 (available on request).
b. If fish could scream (Project Syndicate) http://www.project-syndicate.org/commentary/if-fish-could-scream
c. Care2makeadifference http://www.care2.com/causes/fish-feel-fear-and-pain-and-stress.html
d. Website that references Discovery news feature (Discovery page itself
is no longer available):
e. PETA website sections on fishing for food (http://www.peta.org/issues/animals-used-for-food/fish-feel-pain.aspx)
and for sport
both reference the UoE research.
f. Fishcount website: http://fishcount.org.uk/
or http://tinyurl.com/pyqpwrs ;
(copy also available on request)
g. Contribution of Braithwaite and Sneddon's research can be corroborated
by the Chair of the committee which produced the APC supplementary review:
Deputy Scientific Director at Universities Federation of Animal Welfare
(UFAW), the independent international animal welfare scientific society.
h. Animal Procedures Committee Supplementary Review of Schedule 1 of the
Animals (Scientific Procedures) Act 1986: Appropriate methods of humane
killing for fish.
(copy of pdf also available on request).
i. EFSA scientific opinion on fish welfare: http://www.efsa.europa.eu/en/efsajournal/pub/954.htm
(copy of report also available on request)
j. Quoted in Freedom Food leaflet:
(copy of pdf also available on request).