Review of biodegradable materials for aquaculture nets: Environmental performance and potential to reduce marine plastic pollution.

The increasing environmental impact of fossil-based plastics in aquaculture has intensified the search for biodegradable alternatives. Biopolymers such as polyhydroxyalkanoates (PHAs), starch-based blends, and bio-based composites show potential to replace polyethylene and polypropylene in ropes and nets used in aquaculture farming. This review synthesizes recent advances in the development, mechanical performance, biodegradation behaviour, and practical implementation of biodegradable materials in aquaculture. Based on recent advances in polymer science, material processing, degradation mechanisms, and field-scale trials, the analyses of the physico-chemical properties that affect durability and biodegradation in marine environments, including crystallinity, hydrophilicity, mechanical performance, UV and thermal stability, and chemical resistance are analysed. Additional attention is given to the influence of environmental factors such as salinity, temperature, hydrodynamic loads, and microbial activity, which collectively regulate hydrolytic, photo-oxidative, mechanical, and biotic degradation pathways. Case studies demonstrate promising mechanical stability and controlled biodegradation, with some prototypes enhancing mussel settlement and overall farm productivity. Despite these advances, challenges remain in achieving an optimal balance between operational durability and timely biodegradation, scaling up production cost-effectively, and establishing harmonized marine biodegradation standards.