Data and code for: Non-native species weaken diversity-mediated stability in aquaculture

Species diversification can stabilize food production, but whether diversity gained through non-native species stabilizes production as effectively as diversity based on native species remains unclear. Using seven decades of FAO aquaculture production records linked to environmental and socioeconomic covariates, we show that non-native species significantly increased aquaculture diversity but simultaneously weakened diversity-mediated stability of aquaculture production. Species portfolios including non-native species had lower stabilizing effects on aquaculture production than native-only portfolios in 74.1% of nations, with a median reduction of 36.3% among those nations. This weakening was associated mainly with reduced mean species stability rather than decreased interspecific asynchrony, and was more pronounced where non-native species contributed a larger share of production, aquaculture area was smaller, and GDP per capita was higher. Food-security strategies should therefore evaluate non-native species for temporal stability as well as productivity, while expanding native species to build portfolios with higher species-level production stability.