Abstract

Patterns of fish distribution within Great Artesian Basin springs fall into two distinct categories: the opportunistic colonisation of springs by widespread riverine species following flooding, and long-term habitation – and speciation – within isolated spring complexes by fishes endemic to certain spring complexes. The endemic fishes of Australia’s Great Artesian Basin springs persist in what some would consider the most unlikely fish habitats imaginable. Within predominantly hot and dry landscapes, they inhabit the only reliable wet areas, which are frequently the same temperature as the surrounding plains and as shallow as the body depth of some of the species. There are seven narrow-range fish species endemic to Great Artesian Basin springs: the Dalhousie catfish (Neosiluris gloveri), Dalhousie hardyhead (Craterocephalus dalhousiensis), red-finned blue-eye (Scaturiginichthys vermeilipinnis), three localised species of gobies (Chlamydogobius gloveri, C. micropterus and C. squamigenus) and the Dalhousie mogurnda (Mogurnda thermophila). These species occur at only three locations: Dalhousie in South Australia; and the Pelican Creek and Elizabeth Springs complexes, which are both in Queensland. An eighth species, the desert goby (Chlamydogobius eremius) has a wider range across multiple spring complexes in South Australia. All GAB endemic spring species should be considered endangered due to their small ranges and small populations; however, their formal status varies widely between state, national and international legislation and/or lists. Additionally, all fish endemic to GAB springs are threatened by a broad suite of factors that endanger inland aquatic ecosystems, such as water extraction, pollution, and the possibility that alien or unwanted species may become established. Persisting as they do in such unique and specialised habitats, the study of these GAB fish – and all GAB springs endemics – can reveal much about evolution, speciation and resilience. Although there is a growing recognition that conservation of the fishes and their habitats is important, this is complicated by the confusing variability of their conservation status and a lack of basic knowledge regarding their ecology and precise distribution.