The rapid loss of reef-building corals owing to ocean warming is driving the development of interventions such as coral propagation and restoration, selective breeding and assisted gene flow. Many of these interventions target naturally heat-tolerant individuals to boost climate resilience, but the challenges of quickly and reliably quantifying heat tolerance and identifying thermotolerant individuals have hampered implementation. Here, we used coral bleaching automated stress systems to perform rapid, standardized heat tolerance assays on 229 colonies of Acropora cervicornis across six coral nurseries spanning Florida's Coral Reef, USA. Analysis of heat stress dose–response curves for each colony revealed a broad range in thermal tolerance among individuals (approx. 2.5°C range in F v /F m ED50), with highly reproducible rankings across independent tests ( r = 0.76). Most phenotypic variation occurred within nurseries rather than between them, pointing to a potentially dominant role of fixed genetic effects in setting thermal tolerance and widespread distribution of tolerant individuals throughout the population. The identification of tolerant individuals provides immediately actionable information to optimize nursery and restoration programmes for Florida's threatened staghorn corals. This work further provides a blueprint for future efforts to identify and source thermally tolerant corals for conservation interventions worldwide.

Non-native populations of Pacific oysters Crassostrea gigas (Thunberg 1793) are established around the United Kingdom (UK), with two genetically different stocks originating from separate introductions to the UK and France. In this study, we use a coupled biophysical model to simulate Pacific oyster larval transport, in order to investigate the dispersal of the species from a known population near their northern limit on the west coast of the UK (in the Milford Haven Estuary). The model included a pelagic phase, simulating different swimming behaviours, and a settlement phase based on a hydrospatial substrate map. Following successful settlement elsewhere, subsequent releases simulated potential population spread over successive generations. Our results suggest that, should there be sufficiently warm sea temperatures to allow reproduction, dispersal away from Milford Haven Estuary would most be southeast ward towards the Bristol Channel; but dispersal north and west to Ireland is also possible, depending heavily on pelagic swimming behaviour. Seasonal modifications to circulation were less influential. Our study increases understanding of factors that contribute to oyster population spread, and suggests methods for improved management through numerical predictions.