Environmental monitoring programmes use fish tagging, sampling, and electrofishing to assess population health, with welfare obligations that vary across monitoring agencies and methodologies.
Wildlife monitoring causes unavoidable welfare costs in exchange for data that benefits populations and ecosystems. In fish monitoring, the primary welfare obligations are to minimise the intensity and duration of electrofishing exposure, ensure adequate recovery before release, use the least invasive tagging method appropriate to the research question, and provide appropriate post-surgical care for internally tagged fish. When monitoring is well-designed and humanely conducted, the welfare cost is brief and the individual fish typically recovers completely. When it is poorly designed — with excess current, inadequate recovery time, or poorly conducted surgery — it causes injury and mortality that degrades both welfare and data quality. Professional standards and ethical review should apply to monitoring as rigorously as to formal research.