Fishing net. Photo by Bicanski, Pixnio.
If humanity wants to continue to feed on wild-caught fish – as 40 per cent of the global population currently does – it is crucial that fisheries managers and marine conservationists start using the same metrics to evaluate the effectiveness of both sustainable fisheries measures and the establishment of marine protected areas.
A recent study published in Marine Policy shows that, so far, these two sets of actors have had disparate and sometimes conflicting agendas when it comes to their respective marine conservation goals. These goals were established in the 2022 Kunming-Montreal Global Biodiversity Framework (GBF) as target 5 and 10, which propose that all fisheries areas are to be sustainably managed by 2030 so that they can continue to provide ecosystem benefits and services (aka seafood), and target 3, which advises the expansion of marine protected areas coverage to 30 per cent of the ocean by 2030 to rebuild marine biodiversity.
“These goals are intrinsically connected as they support both conservation outcomes and the maintenance or even the increase of fishery productivity,” said Dr. Boris Worm, lead author of the paper and a professor at Dalhousie University. “Yet, we found little evidence of integration when looking at the 19 major fishing areas in which the Food and Agriculture Organization of the UN has divided the global ocean. Across those areas, on average, 62 per cent of assessed industrialized fisheries were reported within sustainable limits, while protected area coverage averaged 10 per cent, with only 3 per cent highly or fully protected.”
According to Dr. Worm, in most jurisdictions, a fundamental challenge lies in the institutional disconnect between agencies tasked with assessing and protecting biodiversity and those that assess and manage fisheries, often leading to poor coordination or conflict over the designation of protected areas.
“Fisheries management typically aims to maximize long-term benefits while maintaining a productive fish stock and ecosystem. This is usually achieved via managing target species close to the biomasses that support maximum sustainable yields. This is different from biodiversity conservation objectives, which aim to restore the abundance and diversity of all species to a level closer to the biomass achieved in the absence of fisheries exploitation and other industrial uses,” Dr. Worm said.
The disconnection goes even further, with some Regional Fisheries Management Organizations (RFMOs), which operate in specific sections of the high seas, having used closed areas as effective fisheries management measures, yet keeping these areas separated from large-scale MPAs in the same regions. In consequence, the joint benefits of these mechanisms are lessened instead of boosted.
“There is strong evidence that well-placed and managed protected areas can support nearby fisheries through spillover of larval and adult fish,” said Dr. Daniel Pauly, co-author of the study and principal investigator of the Sea Around Us initiative at the University of British Columbia. “In addition, the protection of fish habitat can help shelter vulnerable life stages, while elevated biomass, diversity, and reproductive capacity can help build resilience to the effects of climate change.”
The authors propose a model in which management actions aim to increase community biomasses to those which would support maximum sustainable yields, while at least 30 per cent of the targeted areas are to be designated as MPAs with other effective area-based conservation measures (OECMs) in place, including and respecting Indigenous and Traditional Territories.
They also recommend that both environmentalists and sustainable fisheries managers use community biomass – the total weight of fish, invertebrates, or other marine species within a given space — as a robust, well-established indicator of abundance, which helps track depletion and recovery of marine life.
“The effectiveness of area-based conservation measures implemented for Target 3 needs to be considered in the context of expected fishery outcomes under Targets 5 and 10. Fisheries management measures primarily aimed at achieving maximum sustainable yield should not be counted as progress toward Target 3, nor should MPAs or OECMs that fail to achieve recovery outcomes above what is expected under sustainable fisheries management,” Dr. Pauly said. “This assessment framework provides a straightforward avenue for correctly classifying area-based management measures as contributions towards either Target 3 or Target 10, and for verifying their effectiveness relative to each other and against quantifiable reference points.”
The paper “Integrating global targets for protected areas and sustainable fisheries” was published online in Marine Policy, https://doi.org/10.1016/j.marpol.2026.107152