Assessment - Selection of appropriate welfare indicators
It is recognised that no single indicator can be used to reliably assess fish welfare, but that a number of different indicators must be selected that can be related to different aspects of an animal’s welfare (FSBI, 2004). Such indicators should be practical, feasible and valid (Spoolder et al. 2004). The table below is by no means inclusive but lists some commonly measured parameters that can be grouped into different areas of welfare infringement based on the Five Freedoms of animal welfare.
Suggested welfare indicators that could be practically applied to measure different types of welfare infringement
| Type Welfare Infringement | Suggested Indicators |
|---|---|
| Freedom from hunger, thirst and malnutrition | Feed intake and performance indicators; growth rates, condition factor |
| Freedom from pain, injury and disease | Physical damage: fin condition, cataracts, lesions. Immune responses e.g. lysozyme activity, respiratory burst activity, phagocytic activity |
| Freedom from discomfort | Environmental monitoring: water quality monitoring (dissolved oxygen, ammonia, pH carbon dioxide, suspended solids)
Targeted sampling of fish: gill condition and checking for parasite infestation |
| Freedom to exhibit normal behavior | Abnormal behavior: Swimming and feeling behavior, distribution of the fish within a system (eg clumping around inflows), response of fish to an approaching farmer |
| Freedom from fear and distress | Measuring primary and secondary stress responses: plasma, cortisol, glucose, lactate |