Do mariculture products offer better environment and nutritional choices compared to land-based protein products in China?

Mariculture products are generally deemed to have less negative environmental externalities and more nutrient content, and are therefore a promising food substitute for land-based protein products (LPPs). China is the world's largest mariculture producer, with 66% of global production share in 2018. However, different categories of mariculture products have varied nutrient composition and environmental impacts, and ignoring such heterogeneity potentially misleads policy decision making in mariculture development in China. Here, we compare the environmental and nutritional performance of 28 mariculture products with 7 LPPs produced in China. Our results show that although mariculture products are more environmentally friendly than LPPs on the whole, not all mariculture products have better nutrition-environmental performance than LPPs. Only 17 out of 28 mariculture products, mainly shellfish and fish, are found to be both nutritionally and environmentally more friendly than LPPs. Shellfish are promising substitutes for LPPs due to their minor environmental impact, higher nutrient density, greater production volume and lower average price compared with other mariculture products. However, upper dietary limits on daily intake of shellfish due to potential overconsumption of certain micronutrients must also be considered. We also found mariculture derived fish have no distinct environmental, nutritional or cost benefits over some LPPs, such as egg and chicken. The current structure of the mariculture industry in China may be optimized by expanding the production of nutrient-rich mariculture products with low environmental impact and affordable price.