Rethinking material use in low-trophic aquaculture: A global review

Low-trophic aquaculture (LTA), including seaweed and bivalve farming, is often promoted as an environmentally sustainable food production system due to its low input requirements and potential ecological benefits. However, this sustainability narrative is increasingly undermined by the pervasive use of plastic-based gear. This systematic review of 1,768 peer-reviewed publications (2003-2024) reveals that synthetic polymers remain the dominant material in LTA infrastructure, contributing to marine litter, microplastic pollution, and long-term ecological degradation. Although one-third of studies mentioned farming gear, only 6 % (n = 108) disclosed the material composition, indicating a critical gap in sustainability reporting. Among these, over 70 % referenced conventional plastics such as polyethylene, polypropylene, and nylon. Regional and species-level differences emerged: natural materials were more frequently reported in Asian seaweed farming, whereas non-Asian studies were more likely to explore biodegradable or bio-based alternatives. Nevertheless, plastics remained prevalent across all contexts, particularly in bivalve systems (up to 88.2 % in Asia). Sentiment analysis of abstracts revealed regional differences in research framing, with Asian studies adopting a more pragmatic tone and non-Asian studies engaging more critically with environmental issues. These findings underscore the urgent need to address plastic dependence in LTA and promote scalable, regionally tailored alternatives through improved policy, reporting, and innovation pathways.