Effects of aquaculture on the maintenance of waterbird populations

Abstract The global aquaculture industry has expanded rapidly and is increasingly important for maintaining food security and providing habitat for many waterbirds. Clarifying how waterbirds use aquafarms and how aquafarm use affects waterbird population maintenance can help improve management of the aquafarm landscape such that it can provide habitat for waterbirds. We investigated aquafarm use by waterbirds in China, the world's largest producer of aquaculture products. We used data from the literature on and expert knowledge (questionnaire survey) of waterbird use of aquafarms in China and Bayesian phylogenetic generalized linear mixed models to analyze the relationship between the degree of aquafarm use and population trends of waterbirds. Sixty‐nine percent of waterbird species in China have been recorded at aquafarms. Approximately one quarter of all waterbird species and about the same proportion of threatened species were found to forage at aquafarms, consuming either cultured aquatic products or other food stuffs. In general, species with a high degree of aquafarm use were unlikely to exhibit a population decline over the past 2 decades, when rapid loss of natural habitat occurred in China. This relationship was not detected in threatened species, despite there being no significant difference in the degree of aquafarm use between threatened and nonthreatened species. Our results suggest that the large and expanding aquaculture industry is important for maintaining waterbird populations in China. However, aquafarms are not a replacement for natural habitats because threatened species benefited less from aquafarm use. Given that aquafarms often negatively affect natural wetlands, the degree to which aquafarms compensate for natural habitat loss probably depends on the quality of aquafarm habitat and the habitat requirements of waterbirds. We recommend an integrated ecological and economic analysis to formulate management policies that help conserve wildlife within the constraints and opportunities associated with maintaining human livelihoods.