The question of pain in fish has been subject to much debate and, since fish are a popular experimental model globally and commercially important in fisheries, recreational angling and aquaculture, many procedures that fish are subjected to cause tissue damage. These injuries would give rise to the sensation of pain in humans but whether fish have the capacity for pain is relatively under explored and is a contentious issue. This presentation shall review the recent empirical evidence that has shown that fish have the same neural apparatus to detect pain that mammals and humans do, that their brain is active during a potentially painful experience, that fish show negative changes in behaviour and physiology and that this is reduced by administering an analgesic. Experiments demonstrating the significance of pain to trout and zebrafish have been conducted and have shown that fish do not show appropriate fear and anti-predator responses during a painful stimulation. This suggests that they are dominated by the pain state confirming its importance to the fish. However, social context affects the aggressive behaviour of trout when noxiously stimulated. In a familiar group, dominant trout perform much less chasing of conspecifics yet this suspension in aggression is not seen when placed in an unfamiliar group of fish. The latest findings on zebrafish seeking analgesia will be presented to demonstrate that fish are willing to pay a cost to accessing pain relief. Therefore, responses to pain are more complex and not simple reflexes. Together, these results demonstrate that painful events are important for fish and we should seek to minimise and alleviate pain where possible. The latest research findings on identifying robust indicators to assess pain in fish shall be discussed alongside the current knowledge on the use of anaesthetics and analgesics.
Medical Laboratory Technician33%