Climate-driven range expansion via long-distance larval dispersal

Climate-driven warming and changes in major ocean currents enable poleward transport and range expansions of many marine species. Here, we report the population genetic structure for the gastropod Kelletia kelletii , a commercial fisheries species and subtidal predator with top-down food web effects, whose populations have recently undergone climate-driven northward range expansion. We genotyped 598 adults from 13 locations across the species’ historical and expanded range ( ∼ 800 km) using reduced representation genomic sequencing (RAD-seq). Analyses of 40,747 SNPs show evidence for long-distance larval dispersal of K. kelletii larvae from a central historical range site (Point Loma, CA) hundreds of km into the expanded northern range (Big Creek, CA), which seems most likely to result from transport during an El Niño Southern Oscillation (ENSO) event rather than consistent on-going gene flow. Furthermore, despite smaller geographic distances among some sampled expanded-range populations, their genetic divergence exceeds that among the historical range sampled populations, suggesting multiple origins of the expanded-range populations. Given the frequency and magnitude of ENSO events are predicted to increase with climate change, understanding the factors driving changes in population connectivity is crucial for establishing effective management strategies to ensure the persistence of this and other economically and ecologically important species.