Social implementation and LCA: Valorization of unused herbivorous fishes to protect seaweed beds

Abstract

Degradation of coastal algal beds, driven in part by herbivorous fish grazing, threatens marine biodiversity and blue carbon sequestration. Addressing this challenge requires both ecological restoration and sustainable resource utilization. This study evaluates two contrasting approaches to managing underutilized herbivorous fish: governmental removal and incineration programs, and private-sector valorization as pet food. By integrating blue carbon sequestration into life cycle assessment, the study aims to compare their environmental, economic, and social implications. We applied an extended LCA framework incorporating ecosystem services. The governmental scenario included fish removal, incineration, and carbon uptake from algal bed recovery. The private scenario covered fishing, processing, pet food production, and associated blue carbon benefits. Data were collected from municipal reports, field interviews, and feeding trials with companion animals. The governmental scenario contributed significantly to CO₂ absorption but depended heavily on subsidies and faced limitations in resource circulation and animal welfare. The private scenario demonstrated potential carbon-negative performance and market acceptance, yet relied strongly on consumer demand and market dynamics. Both approaches are complementary. A hybrid strategy may enhance fisher incentives and resource circulation. Future research should examine consumer perception, integrate LCA with biodiversity metrics, and assess fisher well-being as a key dimension of social sustainability.