Scientific tagging of fish for research is essential for conservation but involves welfare impacts that require careful consideration and minimisation.
Fish tagging involves procedures that cause acute pain and physiological stress even with anaesthesia. Post-tagging recovery requires appropriate water conditions and protected environments. External tags on small fish can alter swimming hydrodynamics and increase vulnerability to predation. The scientific value of tagging data for conservation is considerable, but the welfare costs require balancing against the benefits and minimisation of harm per individual.