Genetics key to sustainable fisheries management

Genetic research could reshape fisheries management across the North-East Atlantic, with a major review by Denmark’s DTU Aqua revealing that almost half of existing stock assessment units do not accurately reflect the genetic populations of commercially important fish species.

The study examined 40 years of genetic and genomic research covering 42 commercially important species. Researchers found mismatches between genetic evidence and management boundaries in 30 of the 34 species for which genetic information was available. Overall, 47% of stock assessment units examined showed discrepancies, while only 36% were fully supported by genetic data.

“To manage fisheries sustainably, we need to know which populations exist and where they are,” said Sara Maggini, postdoctoral researcher at DTU Aqua and the study’s lead author.

The findings highlight the risk of managing several genetically distinct populations as a single stock. Vulnerable populations could decline unnoticed when their condition is masked by healthier groups, potentially creating an overly optimistic assessment of overall stock health and resilience.

The researchers also stressed that genetic diversity is essential for helping fish populations adapt to climate change and shifting marine ecosystems. Traditional management measures, including maximum sustainable yield, focus primarily on stock abundance rather than the genetic capacity needed to withstand future environmental pressures.

Genetics is already influencing fisheries policy. Genomic evidence has contributed to revisions of stock boundaries used by the International Council for the Exploration of the Sea for Atlantic cod, herring, horse mackerel and sprat.

The study, which reviewed 302 scientific investigations, found that 83% identified genetic differences between populations.

Researchers recommend combining genetic monitoring with conventional fisheries surveys, tagging studies and migration analysis. Tissue sampling and environmental DNA could help identify changing population distributions and provide early warnings when management boundaries no longer reflect biological realities.

Maggini said conserving genetic diversity must become a greater priority to protect biodiversity and ensure resilient fish populations in changing oceans.