The Montebello’s are among the State’s most distant continental islands and despite the introduction of exotic mammals and disturbance from atomic weapons testing, the islands and their surrounding waters still support a diverse and interesting array of terrestrial and marine fauna.
Montebello Islands’ mangrove communities considered globally unique as they occur in lagoons of offshore islands. the Montebello Islands region is home to one of the highest number (633 species).
Ten species of cetaceans are recorded from the reserves, with the Humpback whale passing through the area during its annual migration. Dugongs are found in the shallow warm waters.
Whale species that may occasionally visit the Montebello/Barrow islands region include the Humpback whale (Megaptera novaeangliae), short-finned pilot whale (Globicephala macrorhynchus), false killer whale (Pseudorca crassidens), killer whale (Orcinus orca), minke whale (Balaenoptera acutorostrata), Bryde’s whale (Balaenoptera edeni), sei whale (Balaenoptera borealis), pygmy blue whale (Balaenoptera musculus brevicauda), fin whale (Balaenoptera physalus), melon-headed whale (Peponocephala electra), sperm whale (Physeter macrocephalus) and the blue whale (Balaenoptera musculus musculus). Of these, only the Humpback whale is a regular visitor to the area.
Green, flatback, hawksbill, loggerhead and leatherback turtles are found in the reserves, with the Western Australian hawksbill population being the largest remaining in the Indian Ocean. Four species use sandy beaches in the reserves for nesting. Breeding aggregations of turtles occur in the Montebello Islands along the western edge of the archipelago, south of North West Island, and north of Trimouille Island.
The reserves provide important feeding and resting areas for migrating shorebirds. Islands within the reserves provide nesting areas for at least 15 species of seabirds. The seabird assemblage of the Montebello/Barrow islands region comprises at least 67 species, including 25 species of migratory shorebirds and 20 resident shorebirds.
A rich finfish fauna with at least 456 species. The Montebello/Barrow islands region supports a higher species richness of marine fish than most other parts of tropical Western Australia. A total of 456 fish species from 75 families were recorded from the Montebello Islands during a 1993 Western Australian Museum survey.
A diverse marine invertebrate fauna comprising mostly tropical species. Marine invertebrates are those marine animals without a backbone and include such animals as corals, sponges, rock lobster, crabs, squid, cuttlefish, molluscs, jellyfishes, seastars, anemones and marine worms. The reserves have a high diversity and abundance of invertebrate species, which is attributed to the wide range of habitats.
Coral reef communities
Undisturbed intertidal and subtidal coral reefs and bommies with a high diversity of hard corals.
Coral reef communities occur throughout the reserves. The best developed coral reef communities in the reserves are in the relatively clear water and high energy conditions of the fringing reefs to the west and south-west of the Montebello Islands, and bommies and patch reefs in the more turbid and lower energy waters along the eastern edge of the Montebello Islands.