''Gadopsis'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

temperate perch Percichthyidae, the temperate perches, are a family of freshwater ray-finned fish found in Australia and southern South America. Formerly placed in the order Perciformes, they are now placed in the order Centrarchiformes. The name Percichthyida ...

endemic Endemism is the state of a species being found only 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 foun ...

to freshwater habitats in southeastern Australia. The genus was formerly considered to be in a family of its own, Gadopsidae. This genus and the ''

Maccullochella ''Maccullochella'' is a genus of large Australian predatory freshwater fish within the family Percichthyidae. The genus ''Maccullochella'' was named after an early Australian fish researcher with the surname ''McCulloch''. The ''Maccullochella'' ...

'' cods (such as the

Murray cod The Murray cod (''Maccullochella peelii'') is a large Australian predatory freshwater fish of the genus '' Maccullochella'' in the family Percichthyidae.Dianne J. Bray & Vanessa J. Thompson (2011Murray Cod, Maccullochella peelii Fishes of Au ...

, ''Maccullochella peelii'') are strongly similar. There are some grounds for believing blackfish may be a smaller version of Murray cod, inhabiting similar niches but in habitats are too small for Murray cod (having said this, their distributions originally overlapped substantially), and there are grounds for believing that blackfish and Murray cod have drawn heavily on common genes at the family level.

FishBase FishBase is a global species database of fish species (specifically finfish). It is the largest and most extensively accessed online database on adult finfish on the web.

, for instance, has scrapped the family

Gadopsidae Percichthyidae, the temperate perches, are a family of freshwater ray-finned fish found in Australia and southern South America. Formerly placed in the order Perciformes, they are now placed in the order Centrarchiformes. The name Percichthyida ...

and listed the blackfishes as members of the temperate perch family, '' Percichthyidae''. A

mitochondrial DNA Mitochondrial DNA (mtDNA and mDNA) is the DNA located in the mitochondrion, mitochondria organelles in a eukaryotic cell that converts chemical energy from food into adenosine triphosphate (ATP). Mitochondrial DNA is a small portion of the D ...

study has confirmed a relationship between the Blackfish and the Percichthyidae but the exact relationship was not resolved in that study. Further study is needed to resolve the relationship between the blackfish and the ''Percichthyidae''. In addition, molecular studies have supported the view that ''G. marmoratus'' is a

species complex In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each oth ...

of five different species, these include a species in the Murray-Darling Basin and four species in coastal freshwaters. One of these forms from Victoria has been named as ''Gadopsis gracilis''. Blackfish have a recruitment method similar to Murray cod, but with more specialisation to upland habitats. Blackfish spawn in spring and lay a very limited number of large, adhesive eggs (<1000) on sunken timber (

snags In forest ecology, a snag is a standing dead or dying tree, often missing a top or most of the smaller branches. In freshwater ecology the term ''snag'' refers to trees, branches, and other pieces of naturally occurring wood found sunken in riv ...

), or in the case of two-spined blackfish on submerged rocks. Similar to Murray cod, the male guards the eggs until they hatch. Upon hatching the larval blackfish are, uniquely, attached to their ruptured egg case by a tether until the yolk sac is largely used and the larvae are ready to commence exogenous feeding. (This unique structure is presumably an adaptation to upland river/stream habitats, to prevent larvae being swept away in currents.)

Species

There are two species in this genus: * ''

Gadopsis bispinosus The two-spined blackfish (''Gadopsis bispinosus'') is a species of temperate perch endemic to Australia. It is found in the cool, clear, strong-flowing, cobble bottomed, sub-alpine rivers and streams (ranging from small to large) in the southea ...

'' Sanger, 1984 (Two-spined blackfish) * ''

Gadopsis marmoratus The river blackfish (''Gadopsis marmoratus'') is a freshwater fish endemic to the temperate waters of south-eastern Australia. It is found from southern Queensland through to central Victoria, including in the Murray- Darling river system. I ...

'' J. Richardson, 1848 (River blackfish)

References

Percichthyidae Taxa named by John Richardson (naturalist) Freshwater fish genera {{Perciformes-stub