Stress and welfare in teleost fish

Dr. Neil Ruane

Marine Institute

Awareness of Fish Welfare

Awareness of Fish Welfare

Directive 98/58/EC – protection of animals kept for farming purposes.

EC. 2002. A strategy for the sustainable development of European aquaculture. Commission of the European Communities COM (2002) 511 final, 26 pp.

“promotion of animal health and welfare as one of the three main objectives for the sustainable development of European

aquaculture”

ec.europa.eu/food/animal/welfare/index_en.htm

Council of Europe – European Convention on the protection of animals kept for farming purposes: Recommendations for farmed

fish (06/2006)

www.coe.int

In 2008 the World Organisation for Animal Health (OIE) adopted guiding principles for fish welfare

www.oie.int

Awareness of Fish Welfare

European Food Safety Authority – Animal Health & Welfare Panel: risk assessment of the welfare of 6 species (salmon, trout, sea

bream, sea bass, eel, carp) – basis for future legislation?

www.efsa.europa.eu

In 2009 the AHAW panel adopted an opinion on the general approach to fish welfare and produced documents on stunning

and killing methods for 7 species (tuna, carp, salmon, trout, sea bream, sea bass, eel and turbot).

Concept of fish welfare

• Animal welfare refers to the quality of life or well-being

• applied to sentient beings (self awareness, experience pain, suffering)

• controversial area in fish biology

• duty of care to the animals

• Who cares?

- Producers: responsibility; image; CoP’s; profitability

- Processors: flesh quality; reputation

- Scientists: research opportunity; funding; obligation

- Welfarists: genuine concern (RSPCA; Freedom Foods); PR

- Consumers/Retailers: consumer perception; education; sales

Awareness in fish

Watching other fish fighting increased androgen levels in spectator fish

Androgens – sex hormones; social status; agressiveness

Concious or reflex?

Dangers of anthropomorphic explanations

Whether fish are sentient or not, the exposure of

fish to stressors/poor conditions should be

avoided or kept to a minimum

On-farm Stressors

HandlingConfinement

Stocking densityAir exposureVaccination

Culture system

Culture proceduresWater Characteristics

Behavioural Interactions

Chemical componentsTemperatureSalinityO2

HardnesspH

Interspecific competitionSocial dominance

Territoriality

Welfare indicator: 1o stress response

Hypothalamus

CRH

Pituitary

ACTH

Head kidneyChromaffin cells Interrenal cells

Cortisol

MANY SITES OF ACTION

Sympatheticnerves

Catecholamines

Interrenal cells in carp head-kidney

Secondary responses:

- energy mobilisation (increased glucose, fatty acids)

- changes in the immune system (reduction in circulating lymphocytes)

- ion (Na+, Cl-) levels change in the blood

Tertiary responses:

- reduced growth/poor appetite

- immune suppression/disease outbreak

- impaired reproduction

Welfare indicator: 2o & 3o responses

Link between stress and disease

Winter disease - Gilthead seabream (Sparus auratus)

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Tort et al., 1998. Comparative Biochemistry & Physiology A 120: 175-179

Fig. 2. Cumulative mortality of the cohabitees (Atlantic salmon) after IPNV challenge from day 0 to 47 post-challenge, shown as mean±SE. Description: ▴: non-challenged fish and represents both the normoxic and hyperoxic group, ●: Challenged, hyperoxygenated group, ■: Challenged, normoxic group. Ndead=110.

Link between stress and disease

Fridell et al., 2007. Aquaculture 270: 23-35

Link between stress and growth

Daily exposure to stress reduces growth in juvenile carp

Ruane et al., 2007. General Comparative Endocrinology 150: 473-479

Many disease outbreaks occur during the first months of transfer to sea

- stress of transportation

- prolonged stress leads to immunosuppression

- smolts are more sensitive to stress compared with parr

Carey & McCormick, 1998. Aquaculture 168: 237-253

Stress/welfare on the farm - transport

Commercial well boat transport of Atlantic salmon

- loading more stressful than unloading

- stressful transport linked with high mortalities

- well boats can play a role in recovery of the fish

Iversen et al., 2005. Aquaculture 243: 373-382

Effects of environmental noise initially focussed on sonar, pile driving, seismic air guns -

Now looking at aquaculture – chronic exposure to noise

Fish have highly developed sensory systems

- hearing: combination of the lateral line and ear

Hearing specialists – cyprinids (still water more quiet)

Hearing generalists – salmonids (fast flowing rivers more noise)

Stress/welfare on the farm - noise

Effects of noise:

-Induces a stress response in exposed fish

- Can induce temporary hearing loss

- Specialists more sensitive

- Fish can recover over time

Smith et al., 2004. Journal of Experimental Biology 207: 427-435

Stress/welfare on the farm - noise

Monitoring Welfare/Stress on farms - OWI

• Many methods of monitoring stress are a stressor in themselves

• There is a need for non-invasive welfare/stress monitoring

- Operational Welfare Indicators (OWI)

- observe behaviour, remote sampling

- measurement of cortisol, or other stress-activated compounds, in urine, faeces or water

Ruane & Komen, 2003. Aquaculture 218:685-693.

Monitoring Welfare/Stress on farms - OWI

Operational Welfare Indicators – factors which can be corrected

Direct OWI’s – relate to the fish

Indirect OWI’s – relate to the system

Practical OWI’s:

• Farm conditions

• Water quality

• Behaviour/appearance

• Nutrition/feeding

• Health

• Serology/physiology

AQUAFIRST – selective breeding to improve disease and stress resistance in fish and shellfish

http://aquafirst.vitamib.com

FASTFISH – on farm assessment of stress levels in fish

http://fastfish.imr.no

FINE FISH – reduction of malformations of juvenile fish in hatcheries

http://www.finefish.info

COST 867 – a network on fish welfare in European aquaculture

http://www.fishwelfare.com

BENEFISH – benefits and costs of fish welfare in European aquaculture

http://www.benefish.eu

EU projects on fish welfare