Reassessing carbon sink fisheries: biogeochemical constraints and ecological-economic-social coupling and governance

Fisheries and aquaculture influence marine carbon cycling, but biological carbon-retention does not necessarily constitute atmospheric carbon dioxide removal. This critical narrative review reassesses carbon sink fisheries, a concept developed in Chinese fisheries research, through an ecological-economic-social framework. Seaweed cultivation, bivalve aquaculture, integrated multi-trophic aquaculture, and fisheries management are distinguished by carbon pathways and evidentiary requirements. Calcification, respiration, atmospheric replenishment, counterfactual production, postharvest fate, and storage durability constrain carbon claims. Recent observations support enhanced carbon burial in some depositional farming environments, whereas carbonate chemistry and system-level analyses do not justify classifying conventional bivalve production as verified marine carbon dioxide removal. These findings are reconciled by distinguishing measured transfers and stocks from additional atmospheric removal that persists over a specified horizon. A practical governance sequence is proposed: define the intervention and baseline, evaluate claim-specific evidence, report removal and avoided emissions separately, and assess economic performance alongside enforceable social and ecological safeguards. Shared monitoring, tenure protection, transparent benefit allocation, and a zero-carbon-credit financing scenario make the framework relevant to small producers. System dynamics is retained as a prospective tool for testing feedback and policy trade-offs; no calibrated simulation is presented. Climate claims should follow demonstrated carbon outcomes, while food production, nutrient removal, habitat protection, and livelihoods can justify distinct policy instruments.