The University of Stirling has contributed to a major international research project to investigate the dangerous pressure China’s aquaculture industry is putting on world fish supplies.
In a new paper in the journal Science, the researchers offer the clearest picture to date of the enormous impact China is having on wild fisheries and present a more sustainable alternative to the current practice of using wild-caught fish to feed farm-raised fish.
China is the world's leading producer, consumer and processor of fish, contributing one-third of the global supply. Its booming aquaculture industry relies increasingly on fishmeal made from wild-caught fish, a practice which depletes wild fish stocks and strains fragile ocean ecosystems.
One of the researchers - the University of Stirling’s Wenbo Zhang, who conducted the research whilst completing his PhD at the University’s internationally renowned Institute of Aquaculture, said: “Our research shows that so significant is China’s impact on the world’s seafood supply chain – the future availability of global seafood will be dependent on how China develops its aquaculture and aqua feeds sector.”
Fishing in the coastal waters of China is poorly-regulated and often indiscriminant. The result is that large volumes of assorted “trash fish” – species that are undesirable for human consumption – end up in animal feeds, including in fishmeal that is fed to farm-raised fish. Many of the species of wild fish used for feeds have been fully exploited or overexploited, and reducing this demand will help protect fragile ocean ecosystems.
One promising solution is to recycle the waste by-products from seafood processing plants across China. This waste, which can be 30-70% of the incoming volume of fish, is often discarded or discharged into nearby waters.
The team’s analysis shows that these processing wastes could satisfy between half and two-thirds of the current volume of fishmeal used by Chinese fish farmers, replacing much of the wild fish currently used in feeds.
Zhang added: “Issues of quality and food safety are two possible obstacles to implementing this fish processing waste alternative because the waste is lower in protein than wild-caught fish and its use also raises concerns about contamination and disease transmission.
“However, these concerns could be addressed by adding alternative plant-based protein sources to the fish feed, and through conducting further research on the safety risks and introducing more efficient regulating of using fish processing waste.”
Lead author, Ling Cao, a postdoctoral scholar at the Center on Food Security and the Environment at Stanford University said: "This is a critical juncture for China. If the country makes proactive reforms to its aquaculture sector, like using fish processing wastes instead of wild fish, and generally reducing the amount of fishmeal in aqua feeds, it can greatly improve the sustainability of the industry. If not, the consequences for the entire global seafood supply chain are going to be really serious."
Led by Stanford University, USA, the research brought together a consortium of scientists from around the world. Zhang worked with colleagues from Leiden University, the Netherlands; the University of Wollongong, Australia; Stockholm University, Sweden; The Royal Swedish Academy of Sciences, Sweden; and Shanghai Ocean University, China.
The University of Stirling’s Institute of Aquaculture is the leading international centre in its field and the largest of its kind in the world. It brings together cross-disciplinary, world class researchers to meet the wide range of challenges faced as aquaculture grows to meet global demands. Stirling’s Aquaculture research performed outstandingly in REF2014 in the Agriculture, Veterinary and Food Science category, with Stirling ranked 4th in the UK and 88% of research being rated as either world-leading or internationally excellent. http://www.aqua.stir.ac.uk/
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