The Bloomfield River cod (''Guyu wujalwujalensis'') or the tropical nightfish, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

temperate perch The members of the family Percichthyidae are known as the temperate perches. They belong to the order Perciformes, the perch-like fishes. The name Percichthyidae derives from the Latin ''perca'' for perch and Ancient Greek ἰχθύς, ''ichthy ...

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. It is only found in an 11-km stretch of the

Bloomfield River The Bloomfield River is a river located in the Wet Tropics of Far North Queensland, Australia, noted for its Bloomfield River cod fish species, found only in the river. Course and features The river rises in the Great Dividing Range below Zi ...

(between two large waterfalls) in northern

Queensland ) , nickname = Sunshine State , image_map = Queensland in Australia.svg , map_caption = Location of Queensland in Australia , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , established_ ...

. These waterfalls appear to have blocked the migration of more aggressive tropical freshwater fish species such as the

sooty grunter The sooty grunter (''Hephaestus fuliginosus''), also known by the name black bream, blubberlips, Northern grunter or purple grunter, is a species of freshwater ray-finned fish, a grunter from the family Terapontidae. It inhabits coastal and inland ...

(''Hephaestus fuliginosus'') that have presumably naturally displaced the Bloomfield River cod from its former range in prehistoric times. With its very limited distribution, the Bloomfield River cod is clearly a relict species. It is a very important

relict species In biogeography and paleontology, a relict is a population or taxon of organisms that was more widespread or more diverse in the past. A relictual population is a population currently inhabiting a restricted area whose range was far wider during a ...

, however, as it is the most northerly distributed percichthyid species in Australia, and raises interesting questions on the

biogeography Biogeography is the study of the distribution of species and ecosystems in geographic space and through geological time. Organisms and biological communities often vary in a regular fashion along geographic gradients of latitude, elevation, ...

of percichthyid fish in Australia and the history of their ancient colonisation of Australian rivers. The species name ''wujalwujalensis'' comes from the

Wujal Wujal Wujal Wujal is a rural town and locality in the Wujal Wujal Aboriginal Shire, Queensland, Australia. In the , Wujal Wujal had a population of 282 people. It is an Aboriginal community. The community of Wujal Wujal is located in the Cape York r ...

Aboriginal community on the Bloomfield River, and the genus name ''Guyu'' comes from the tribe's name for this fish. Bloomfield River cod are the only species in the genus ''Guyu''. Though named after the Australian freshwater cod species that are the most famous members of the family

Percichthyidae The members of the family Percichthyidae are known as the temperate perches. They belong to the order Perciformes, the perch-like fishes. The name Percichthyidae derives from the Latin ''perca'' for perch and Ancient Greek ἰχθύς, ''ichthy ...

(e.g. Murray cod), the Bloomfield River cod has little resemblance to the cod species. In fact, it is very similar in shape and appearance to a juvenile

golden perch The golden perch (''Macquaria ambigua'') is a medium-sized, yellow or gold-coloured species of Australian freshwater fish found primarily in the Murray-Darling River system, though a subspecies is found in the Lake Eyre-Cooper Creek system, an ...

in a gold/light bronze colouration. It can reach a length of SL.

References

{{Taxonbar, from=Q4928258

Bloomfield River cod The Bloomfield River cod (''Guyu wujalwujalensis'') or the tropical nightfish, is a species of temperate perch endemic to Australia. It is only found in an 11-km stretch of the Bloomfield River (between two large waterfalls) in northern Queensla ...

Freshwater fish of Queensland

Taxobox binomials not recognized by IUCN moved to Latin name redirect a-->