High connectivity and genetic diversity in the Endangered endemic white-spotted sand bass ‘camotillo’ (Paralabrax albomaculatus) within the Galápagos Marine Reserve

Abstract Background Paralabrax albomaculatus , known as the camotillo or white-spotted sand bass, is a finfish endemic to the Galápagos Islands. An important species in the artisanal fishery, P. albomaculatus has undergone heavy population declines in recent decades, and is categorised as Endangered by the IUCN. Despite its socio-economic importance and endemic status, nothing is currently known about the population structure of the species, impeding evidence-based fisheries management. In this study, we use microsatellite markers to investigate its population structure and genetic diversity over the east, south and west of the Galápagos archipelago. Results We found evidence of high connectivity across the archipelago, with the species constituting a single population. We also found that genetic diversity was high, despite fishing pressure and recorded ongoing population declines. Conclusions Our results suggest that P. albomaculatus should be managed as a single fishery stock across the Galápagos. As a single-population species and fishery, managers should also be aware that P. albomaculatus is inherently vulnerable to perturbation as recruitment from other populations is not possible in the event of population decline. However, high genetic diversity gives cause for cautious optimism regarding the genetic capacity for resilience of the population to novel environmental stressors. These results should aid in the implementation of a species-specific management plan for this Galápagos endemic.