Enigmatic declines of Australia’s sea snakes from a biodiversity hotspot. Survey of seasnakes at Ashmore Reef, Australia (1973 - 2007)

Surveys conducted in eight years between 1973 and 2010 recorded the highest abundances (average 42–46 snakes per day) and species richness (nine species) in 1973 and 1994. In 2002 abundance had declined by more than 50% (21 snakes per day) and only five species were recorded. Since 2005 abundances have been consistently low (1–7 snakes per day), with just two species, Aipysurus laevis and Emydocephalus annulatus, recorded in significant numbers. Despite extensive searches since 2005 (especially in 2010) five species of sea snake historically abundant at Ashmore Reef have not been sighted and are presumed to have become locally extinct. These species include three Timor Sea endemics Aipysurus apraefrontalis, Aipysurus foliosquama, Aipysurus fuscus, and one Australasian endemic Aipysurus duboisii.