 Sightings of the humpback whale ("Megaptera novaeangliae"), followed by southern rights ("Eubalaena australis"), are common between April and October, when the whales are migrating.Other marine mammals sometimes sighted at the islands include pygmy Bryde's whale ("Balaenoptera edeni"), orca ("Orcinus orca"), bottlenose dolphin ("Tursiops aduncus"), common dolphin ("Delphinus delphis"), and striped dolphin ("Stenella coeruleoalba").The green turtle ("Chelonia mydas") and the loggerhead turtle ("Caretta caretta") both live in the waters off the Houtman Abrolhos, albeit in low numbers.