The pygmy killer whale (Feresa attenuata) is a rarely sighted cetacean species that is currently believed to be confined to tropical and subtropical waters. This paper presents four sightings off the east coast of Australia that are believed to be the most southerly sightings of pygmy killer whales worldwide (approximately 37.31°S) and extend the range of this species into temperate regions of Australia. Group sizes ranged from 20–70 individuals and on two occasions a second cetacean species was noted in the presence of the pygmy killer whales. All four sightings occurred when water temperatures were particularly warm for the area (21–25.8°C) and demonstrate the potential for changes in the strength of warm water currents to influence species distributions.

The cetacean fauna inhabiting the poorly-studied waters of the eastern tropical Atlantic (ETA), along the west coast of Africa, is still being described. Information on the cetacean species occurring in specific ETA range states is important for understanding their geographical distribution ranges and for implementing conservation and management measures. Here we provide photographically-verified records for the occurrence of pygmy killer whale (Feresa attenuata) off Côte d'Ivoire and of Fraser's dolphin (Lagenodelphis hosei) off Gabon. These records represent new range state records for both species, and are also the first verified at-sea sightings in the ETA and the Gulf of Guinea respectively.

A total of 168.4 hours of visual cetacean survey work was carried out in association with two geophysical surveys in Montserrat waters (eastern Caribbean) during December 2007 and May 2010, using a seismic vessel as a platform of opportunity. Nine cetacean sightings were recorded: pantropical spotted dolphin Stenella attenuata (N = 2), Fraser's dolphin Lagenodelphis hosei (N = 1), sperm whale Physeter macrocephalus (N = 1), humpback whale Megaptera novaeangliae (N = 1), and sightings of unidentified dolphins (N = 1) and large whales (N = 3). A total of 73.3 hours of acoustic monitoring effort was carried out during December 2007, resulting in 19 cetacean detections. Sperm whale (N = 10) and unidentified dolphin (N = 7) detections predominated. Two acoustic detections were of pantropical spotted dolphins, corresponding with visual sightings. An opportunistic sighting of 14 pygmy killer whales Feresa attenuata during October 2008 was reported. Although the humpback whale was known previously for Montserrat waters, the sightings of other species represent the first verified records for the state.

The pygmy killer whale (Feresa attenuata) is a small cetacean that can be found worldwide in offshore tropical and warm temperate waters. Most information about F. attenuata has been attributed to stranded or accidentally caught specimens and rarely through observation of free-ranging individuals. There is very little information about this cetacean in South Atlantic waters. In Brazil, only two confirmed strandings and four sightings have been published up to date. In this study we present the third confirmed stranding of the pygmy killer whale on the Brazilian coast. The current and previous records of Brazilian specimens suggest that F. attenuata may eventually use the continental shelf to feed and rest, principally in some areas of the Brazilian waters where this oceanographic feature is narrow.

The pygmy killer whale, Feresa attenuata Gray, 1874 can be found worldwide in deep tropical and warm temperate waters remaining one of the least known species of small cetacean. In the tropical and temperate Atlantic, F. attenuata has been recorded from south-east United States, Veracruz, Mexico, the Bay of Biscay, Sénégal, the British Virgin Islands, Guadeloupe, Puerto Rico, and Venezuela. A stranding record for Argentina may be considered a vagrant. In Brazil, only two confirmed stranding records are published and sightings are rare. We here report on two early confirmed sightings of pygmy killer whales, Feresa attenuata off the Brazilian coast previous to the report of Rossi-Santos et al. (2006). Pygmy killer whales could use the edge of the continental shelf occasionally for resting or feeding, such as several other pelagic species do frequently. In conclusion, F. attenuata is known to occur off the Brazilian coast, in deep tropical waters, and may visit the continental slope occasionally for feeding and resting.

Pygmy killer whales, Feresa attenuata were sighted for the first time off the Brazilian coast, SW Atlantic Ocean.