Prospects of multipurpose biomonitoring for fisheries assessment based on environmental nucleic acids

Methods using environmental nucleic acids have become highly effective for monitoring aquatic biodiversity, with an array of suitable use cases, including metrics for fisheries assessment. Traditional methods for assessing fish populations often rely on invasive techniques with limited spatial and temporal coverage. Environmental DNA (eDNA) has revolutionised biomonitoring assessments by facilitating species detection and abundance estimation in a noninvasive and indirect manner. Environmental RNA (eRNA) offers a promising complement by capturing the transcriptional activity of organisms. In addition, the study of eDNA methylation may provide an avenue for detecting the regulation of the expression of genes of interest. This review highlights the opportunities to unlock the full potential of eDNA and eRNA in supporting sustainable fisheries assessment by offering noninvasive, alternative and complementary methods for age assessment, sex identification and reproductive stage, physiological and health status, genetic structure and stock identification. By integrating these innovative approaches with traditional methods, a more comprehensive understanding of aquatic ecosystems can be achieved, ultimately leading to improved fisheries conservation and management decision-making.