Aquaculture Mortality Removal: Fish Welfare in Death and Dying

Timely removal of dead and moribund fish from aquaculture systems is a key welfare and biosecurity practice, yet is often neglected in intensive systems.

Key Facts

Moribund fish (dying but not yet dead) may suffer for hours or days if not identified and removed
Dead fish in tanks and cages spread disease and reduce water quality, threatening surviving fish
Regular monitoring frequency affects how quickly dying fish are identified and euthanised
Euthanasia by clove oil (eugenol) or percussive stunning provides humane death for moribund fish
Automated monitoring systems using cameras and AI are increasingly used to detect abnormal behaviour

Welfare Considerations

Mortality management in aquaculture is both a welfare and biosecurity concern. Moribund fish showing disease signs, injury, or organ failure may experience prolonged suffering if not identified and humanely euthanised. Regular pen inspection, ideally daily, allows early identification. Training farm staff to recognise early signs of disease and distress is essential. Passive cage designs and high stocking densities make individual fish inspection difficult, making investment in remote monitoring technology increasingly important. Welfare-conscious producers have clear protocols for identifying and humanely ending the lives of moribund fish.

What You Can Do

Support aquaculture welfare certification schemes requiring mortality management protocols
Advocate for mandatory monitoring standards in fish farming regulations
Choose farmed fish products from farms with transparent welfare practices
Support research into automated welfare monitoring technologies for aquaculture