Illas Atlánticas Marine Park — Ons Sector

The Ons Island sector of the Illas Atlánticas National Park protects a spectacular stretch of granite sea floor where submarine channels, caves, and overhangs are packed with filter-feeding life sustained by Atlantic upwelling. Dense aggregations of spider crabs carpet the bottom during their annual mating migrations, while conger eels the thickness of a diver's thigh occupy deep crevices in the cliff base. The park's strict access controls have allowed populations to recover to pre-industrial densities, giving visitors a glimpse of what Galicia's seas looked like before commercial fishing.