Pseudocaranx georgianus Silver trevally PC260017

Silver trevally, ''Pseudocaranx georgianus'', (also known as skippy, skipjack trevally and silver bream) is a

jack Jack may refer to: Places * Jack, Alabama, US, an unincorporated community * Jack, Missouri, US, an unincorporated community * Jack County, Texas, a county in Texas, USA People and fictional characters * Jack (given name), a male given name, ...

of the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Carangidae The Carangidae are a family of ray-finned fish which includes the jacks, pompanos, jack mackerels, runners, and scads. It is the largest of the six families included within the order Carangiformes. Some authorities classify it as the only family ...

found around the coast of Australia and New Zealand.

Description

The fish can grow to a length of and weigh up to . More typically, it has a length of and a weight of . The species can live as long as 25 years. They have compressed and elongated bodies, the upper portion is a bluish-silver colour, the belly is silver, and the sides are a yellow-silver shade. A small black blotch is found on the bony flap covering the gills. The fish have two

dorsal fins A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

, two small, detached spines in front of the rear fin, and a deeply forked tail fin. Between two and four years of age, the silver trevally becomes sexually mature and is able to reproduce. Spawning happens in estuaries and deeper waters between spring and autumn over an extended period; the females can produce between 50,000 and 200.000 eggs over the course of a season.

Taxonomy

The species was first formally described by the biologist

Georges Cuvier Jean Léopold Nicolas Frédéric, Baron Cuvier (; 23 August 1769 – 13 May 1832), known as Georges Cuvier, was a French natural history, naturalist and zoology, zoologist, sometimes referred to as the "founding father of paleontology". Cuvier ...

in 1833 as part of the work ''Histoire Naturelle des Poissons'' as described from the type specimen caught at

King George Sound King George Sound ( nys , Menang Koort) is a sound on the south coast of Western Australia. Named King George the Third's Sound in 1791, it was referred to as King George's Sound from 1805. The name "King George Sound" gradually came into use ...

near Albany in Western Australia. Synonyms include: ''Usacaranx nobilis'', ''Caranx georgianus'', ''Usacaranx georgianus'', ''Caranx nobilis'' and ''Caranx platessa''. It was often confused with the widely distributed anti-tropical species ''

Pseudocaranx dentex The white trevally (''Pseudocaranx dentex''), also known as striped jack,) is a jack of the family Carangidae widespread in tropical and warm temperate areas between 40°N and 47°S, in the Atlantic, Mediterranean, Indian, and Pacific Oceans. It h ...

''.

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.

regards this taxon as a

junior synonym The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linna ...

of ''P. dentex''.

Distribution

The species is found in

estuarine An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environment ...

and coastal waters of southern Australia. On the east coast, it occurs around areas north of Sydney then the range follows the coast south around

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

and around

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

and west through

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

to around areas north of

Perth Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth is ...

. It is also found in waters around New Zealand. Silver trevally are known to frequent rocky areas along

bays A bay is a recessed, coastal body of water that directly connects to a larger main body of water, such as an ocean, a lake, or another bay. A large bay is usually called a gulf, sea, sound, or bight. A cove is a small, circular bay with a narr ...

and coastal waters in depths to . Juvenile fish are often associated with bays, estuaries, and shallower waters of the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

. Adult fish commonly inhabit large bays and inlets and areas of inshore

reef A reef is a ridge or shoal of rock, coral or similar relatively stable material, lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic processes— deposition of sand, wave erosion planing down rock out ...

and over open substrate composed of gravel or sand.

References

{{Authority control georgianus Marine fish of Eastern Australia Marine fish of Southern Australia Fish of the North Island Fish described in 1833 Taxa named by Georges Cuvier