Blue Shark

Photo: Paulo Martins · CC BY-SA

Blue sharks appear off Sagres from May through October, drawn by the cape's upwelling productivity and the schools of mackerel and sardines that aggregate there. As highly migratory oceanic apex predators they are critical to regulating pelagic fish populations across the North Atlantic, yet remain among the most heavily fished shark species worldwide. Their appearance on wreck dives — circling curiously at the edge of visibility — is one of the signature encounters of the Algarve summer season.