Mortality in aquaculture affects millions of fish daily through disease, equipment failure, and handling. How dead and dying fish are managed reveals much about welfare culture within production systems.
Aquaculture mortality management sits at the intersection of routine production reality and welfare ethics. Some level of background mortality is inevitable in large-scale fish production — disease, environmental fluctuations, and handling stress affect even well-managed populations. What is not inevitable is the suffering of moribund fish left to die over hours or days without intervention. A dying salmon gasping at the surface or a lethargic tilapia settling to the pond bottom is experiencing a welfare event that production staff often do not intervene to end humanely, partly because humane killing of individual fish in a production context is practically difficult and not culturally normalised. Best-practice operations establish protocols for identifying and humanely killing moribund fish promptly, removing carcasses frequently, and triggering emergency depopulation procedures before mass mortality events from disease or anoxia impose preventable suffering on large numbers of fish.