Climate change impacts on fish-related ecosystem services: synthesis, network analysis, and strategic pathways for coordinated adaptation

Abstract Climate change is rapidly disrupting fish-related ecosystem services that underpin global food security, economic livelihoods, and cultural identity across both marine and freshwater systems. While impacts are increasingly recognised, disciplinary fragmentation has hindered integrated understanding of how climate-driven changes in fish populations affect ecosystem service delivery. This review makes two integrated contributions: a hierarchical synthesis tracing causal pathways from physical climate drivers through biological and ecological responses to socioeconomic outcomes, and a qualitative network analysis that maps the interconnections, implementation readiness, and strategic sequencing of seven major adaptation strategies. Ocean warming, acidification, deoxygenation, and their increasingly frequent co-occurrence as compound climate events trigger physiological stress and behavioural changes in fish, manifesting as habitat degradation, poleward range shifts (~ 72 km/decade), and food web restructuring. While climate change will produce both ecological winners and losers among fish populations, with some species expanding in range and productivity, net global impacts are projected to be substantially negative. Tropical fisheries may lose up to 30% of catch potential by 2050, threatening protein security for ~ 3.3 billion people; regulating services deteriorate as altered communities disrupt nutrient cycling; cultural services erode through community displacement, disproportionately affecting indigenous and small-scale fishers; and supporting services weaken as biodiversity loss reduces functional redundancy and ecosystem resilience. These impacts generate reinforcing feedback loops that intensify environmental vulnerabilities and compound socioeconomic inequities. Applied qualitative network analysis, integrating structural topology with expert assessment of functional importance and implementation feasibility, reveals early warning systems (80% readiness, composite centrality 0.90) and digital technologies (75% readiness, composite centrality 0.80) as high-readiness enablers that should be prioritised as foundational infrastructure. Ecosystem-based fisheries management (65% readiness) emerges as a central coordination mechanism linking conservation, production, and governance. Strategic sequencing proves critical: information infrastructure enables adaptive management, which facilitates institutional reform. International governance remains the primary bottleneck (35% readiness), emphasising the need for institutional innovation alongside technical solutions. Preserving fish-related ecosystem services requires coordinated, multi-scale adaptation approaches that address technical capacities, governance gaps, and distributional equity.