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

Species diversification can stabilize food production, but whether non-native diversity provides the same stabilizing benefits as native diversity remains unclear. Using seven decades (1951–2020) of FAO aquaculture records and environmental and socioeconomic covariates, we show that all-species portfolios had higher diversity and overall production stability, yet weaker stabilizing effects of diversity than native-only portfolios. Stabilizing effects were lower in 74.1% of the 166 nations assessed, with a median reduction of 36.3% among those nations. This weakening was associated mainly with more destabilizing effects of diversity on mean species stability rather than altered effects on 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.