Matthew Faith

The Biodiversity Beyond National Jurisdiction (BBNJ) Agreement provides a new opportunity to consolidate and achieve global marine environmental goals. Here we focus on how science and technology will support its implementation. We provide an overview of existing scientific knowledge and methods that are scalable to Areas Beyond National Jurisdiction (ABNJ). Reviewing data gaps, challenges and opportunities, we outline solutions and a roadmap focused on enhancing resources and capacity.

Ocean warming is projected to reduce the capacity of the global ocean to support fish biomass. The severity of projected biomass declines, however, is distributed highly unevenly at the global scale, meaning some nations face disproportionate socioeconomic risks from resultant fisheries declines. Here, we apply the IPCC climate risk framework through the lens of fishing grounds to identify global hotspots where climate-driven declines in supportable pelagic fish biomass pose the greatest threat to socioeconomic security. By integrating empirical size-spectrum projections of fish biomass declines (hazard) with present-day fishing effort (exposure) and a novel area-based index of fishing ground socioeconomic vulnerability, we identify risk hotspots around Southeast Asia, the western seaboard of Africa, and the West Pacific. Our projections are corroborated by an ensemble of ecosystem models and compared with historical observations of declining zooplankton biomass in the Northeast Atlantic, suggesting climate-driven fish biomass declines are already underway. Many of the regions we assessed as highest-risk are predominantly targeted by nations with relatively low adaptive capacity and who therefore face the greatest barriers to redistributing fishing effort to lower-risk fishing grounds. Socioeconomic risks could thus be partly mitigated by targeting risk hotspots with area-based interventions that directly support fish stocks, such as the restoration of essential fish habitats and the designation of Marine Protected Areas. Resourcing the development of regionally tailored models for high-risk regions will provide the best evidence for designing specific area-based measures that effectively reduce societal risks, but enforcing such measures will depend upon addressing illegal, unregulated and untracked fishing.

Anthropogenic pressures such as climate change and nutrient pollution are causing rapid changes in the marine environment. The relative influence of drivers of change on the plankton community remains uncertain, and this uncertainty is limiting our understanding of sustainable levels of human pressures. Plankton are the primary energy resource in marine food webs and respond rapidly to environmental changes, representing useful indicators of shifts in ecosystem structure and function. Categorising plankton into broad groups with similar characteristics, known as “lifeforms”, can be useful for understanding ecological patterns related to environmental change and for assessing the state of pelagic habitats in accordance with the EU Marine Strategy Framework Directive and the OSPAR Commission, which mandates protection of the North-East Atlantic. We analysed 29 years of Continuous Plankton Recorder data (1993–2021) from the North-East Atlantic to examine how trends in plankton lifeform abundance changed in relation to one another and across gradients of environmental change associated with human pressures. Random forest models predicted between 57 % and 80 % of the variability in lifeform abundance, based on data not used to train the models. Observed variability was mainly explained by trends in other lifeforms, with mainly positively correlated trends, indicating bottom-up control and/or shared responses to environmental variability were prevalent. Longitude, bathymetry, mixed layer depth, the nitrogen-to‑phosphorus ratio, and temperature were also significant predictors. However, contrasting influences of environmental drivers were detected. For example, small copepod abundance increased in warmer conditions whereas meroplankton, large copepods and fish larvae either decreased or were unchanged. Our findings highlight recent changes in stratification, reflected by variation in mixed layer depth, and imbalanced nutrient ratios are affecting multiple lifeforms, impacting the North-East Atlantic plankton community. To achieve environmental improvements in North-East Atlantic pelagic habitats, it is crucial that we continue to address climate change and reduce nutrient pollution.