Abstract
Aquaculture has expanded and intensified significantly since the mid‐20th century, affecting its contributions to food security, climate change and biodiversity conservation (FCB) outcomes. In particular, shifts in the composition of farmed species affect the sector's potential impacts on sustainable development. Because these impacts are partly driven by the biological traits of the farmed species, tracking changes in trait composition can reveal patterns in how aquaculture contributes to FCB outcomes over time. Here, we analyse spatial and temporal trends in aquaculture species' biological potential to support FCB objectives, using species‐specific food, climate and biodiversity indices derived from a traits‐based fuzzy logic model. We weight these scores by the annual production of major aquaculture species and compare average food, climate and biodiversity indices between taxonomic groups, major geographic regions and across three major time periods. Our results suggest that as aquaculture has intensified, production has increasingly favoured a handful of species with lower potential to achieve FCB goals and more trade‐offs between them since 1980. Improvements in growth rate and feed efficiency through selective breeding and developments in feed technology have likely improved aquaculture's FCB potential over time, but these advances carry trade‐offs and are limited to several key species and regions. Future aquaculture can reverse unfavourable trends through sustainable intensification of high‐scoring, currently‐farmed species and through diversifying production. Bivalves will be particularly important for future aquaculture, as they disproportionately contribute to FCB yet are underrepresented in global production.