Spotted galaxias

Last updated

Spotted galaxias
Spotted galaxias.jpg
Spotted galaxias. The characteristic base colouration and black edges to the fins are not particularly noticeable in this photo
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Galaxiiformes
Family: Galaxiidae
Genus: Galaxias
Species:
G. truttaceus
Binomial name
Galaxias truttaceus

Spotted galaxias (Galaxias truttaceus) is a largish, primarily-freshwater galaxias species found in southern Australia. Spotted galaxias are perhaps the most beautiful of the Australian galaxias species. They are a somewhat tubular, deep-bodied fish, with a dusky brownish-red colouration overlain with dark, haloed spots, dramatic black edges to dorsal, anal and pelvic fins, and a dark diagonal stripe through the eye.

Contents

Distribution

Spotted galaxias has a very wide distribution, being found in southern Victoria, all of Tasmania, offshore islands in between, as well as south-west Western Australia.

On the mainland spotted galaxias is generally recognised as a freshwater fish species with a marine larval phase (larvae are swept out to sea and return to freshwater habitats as early stage juveniles), and thus only found in coastal rivers. Spotted galaxias are generally found in coastal rivers in Tasmania as well, however natural landlocked populations do occur in some freshwater lakes in Tasmania.

Spotted galaxias were assumed not to be native to the Murray-Darling river system, however records of native fish fauna compiled by William Blandowski in the 1850s suggest the species did historically occur there. This may cause a re-evaluation of the spotted galaxias specimens occasionally recovered in the Murray-Darling river system, which until now were assumed to be accidental translocations via the Snowy Mountains Hydro-Electric Scheme.

In Western Australia, spotted galaxias are limited to the Goodga, Angove, and Kent river catchments on the southern coast. All three catchments drain to coastal lakes which are only connected to the ocean during the winter season in wet years. [1]

Habitat, diet, and reproduction

Spotted galaxias, in their juvenile and adult stages, inhabit coastal rivers at low to medium altitude. They prefer cool, flowing rivers in forested catchments with excellent riparian vegetation, good water quality and cover in the form of boulders, sunken logs and overhanging banks.

Spotted galaxias are a predatory fish, feeding in the currents or "drift" similar to exotic trout species. Their diet consists mainly of aquatic and terrestrial invertebrates.

Spawning occurs in winter in rivers [2] . Larvae are swept out to sea and return and migrate back up rivers as early-stage juveniles which initially do not resemble adult fish. Returning juveniles are sometimes intercepted by humans as whitebait, and were severely overfished in previous decades. Landlocked lake populations spawn in spring.

Human use

Before the introduction of exotic trout species to Australia, an introduction that has caused severe problems for the conservation of Australian native fish, spotted galaxias were keenly fished for by early Australian anglers using fly-fishing gear. The species was appreciated for its beauty, its willingness to take wet and dry flies, its game fighting ability on very light tackle, and its relatively large size by galaxias standards, sometimes reaching 30 cm, and commonly 20 cm. (Spotted galaxias appear to have had a larger average size before the introduction of exotic trout species.) A handful of fly-fishers in Australia are now re-discovering the pleasure of fly-fishing for this magnificent native fish with ultra-light fly-fishing tackle.

As mentioned above, early-stage juveniles returning to estuaries were and sometimes still are netted as white bait, which are caught for human consumption.

With their beautiful appearance spotted galaxias have potential as aquarium fish, but do require cool water.

Conservation

Spotted galaxias are threatened by dams and weirs blocking migration and fragmenting river habitats, irresponsible forestry and farming practices that degrade river environments through siltation and other effects, and competition and predation by exotic trout species.

In Tasmanian rivers spotted galaxias numbers are severely depressed when exotic trout species are present (Ault & White, 1994). This is a common phenomena; galaxias species that manage to survive the presence of exotic trout (many species do not) such as spotted galaxias are forced into sub-optimal feeding locations, feeding times and diets by aggressive competition from exotic trout species (McDowall, 2006). Galaxias populations in such situations tend to display lower than normal growth, size and fecundity, raising concerns for their long-term future (McDowall, 2006).

In southern Victoria however many recreational fishermen report that spotted galaxias are found only in the few trout-free streams remaining. Spotted galaxias appear to reach a larger maximum size in these few trout-free streams than in Tasmania. A lack of exotic-trout-free habitat reserved for spotted galaxias and other native fish species in south-eastern Australia generally is a major concern.

Related Research Articles

<span class="mw-page-title-main">Trout</span> Freshwater fish from subfamily Salmoninae

Trout is a generic common name for numerous species of carnivorous freshwater ray-finned fishes belonging to the genera Oncorhynchus, Salmo and Salvelinus, all of which are members of the subfamily Salmoninae in the family Salmonidae. The word trout is also used for some similar-shaped but non-salmonid fish, such as the spotted seatrout/speckled trout.

<span class="mw-page-title-main">Murray cod</span> The largest Australian predatory freshwater fish in the family Percichthyidae

The Murray cod is a large Australian predatory freshwater fish of the genus Maccullochella in the family Percichthyidae. Although the species is called a cod in the vernacular, it is not related to the Northern Hemisphere marine cod (Gadus) species. The Murray cod is an important part of Australia's vertebrate wildlife—as an apex predator in the Murray-Darling River system—and also significant in Australia's human culture. The Murray cod is the largest exclusively freshwater fish in Australia, and one of the largest in the world. Other common names for Murray cod include cod, greenfish, goodoo, Mary River cod, Murray perch, ponde, pondi and Queensland freshwater cod.

<span class="mw-page-title-main">Rainbow trout</span> Fresh-water species of fish

The rainbow trout is a species of trout native to cold-water tributaries of the Pacific Ocean in Asia and North America. The steelhead is an anadromous (sea-run) form of the coastal rainbow trout(O. m. irideus) or Columbia River redband trout (O. m. gairdneri) that usually returns to freshwater to spawn after living two to three years in the ocean. Freshwater forms that have been introduced into the Great Lakes and migrate into tributaries to spawn are also called steelhead.

Steelhead, or occasionally steelhead trout, is the anadromous form of the coastal rainbow trout (Oncorhynchus mykiss irideus) or Columbia River redband trout. Steelhead are native to cold-water tributaries of the Pacific basin in Northeast Asia and North America. Like other sea-run (anadromous) trout and salmon, steelhead spawn in freshwater, smolts migrate to the ocean to forage for several years and adults return to their natal streams to spawn. Steelhead are iteroparous, although survival is approximately 10–20%.

<i>Arripis</i> Genus of fishes

Arripis is a genus of marine fishes from Australia and New Zealand, known as Australian salmon, kahawai and Australian herring. They are the only members of the family Arripidae. Despite the common name, Australian salmon are not related to the salmon family Salmonidae of the Northern Hemisphere, just as Australian herring are not related to herring of the Northern Hemisphere, but belong to the order Perciformes of perch-like fishes. Australian salmon were named so by early European settlers after their superficial resemblance to the salmoniform fishes.

<span class="mw-page-title-main">Australian grayling</span> Species of fish

The Australian grayling is a primarily freshwater fish found in coastal rivers in south-eastern mainland Australia and Tasmania. In past decades it has also been known as the cucumber mullet or cucumber herring, for its cucumber-like odour.

<span class="mw-page-title-main">Galaxiidae</span> Family of mostly small freshwater fish

The Galaxiidae are a family of mostly small freshwater fish in the Southern Hemisphere. The majority live in Southern Australia or New Zealand, but some are found in South Africa, southern South America, Lord Howe Island, New Caledonia, and the Falkland Islands. One galaxiid species, the common galaxias, is probably the most widely naturally distributed freshwater fish in the Southern Hemisphere. They are coolwater species, found in temperate latitudes, with only one species known from subtropical habitats. Many specialise in living in cold, high-altitude upland rivers, streams, and lakes.

<span class="mw-page-title-main">Climbing galaxias</span> Species of fish

The climbing galaxias or kōaro is a fish of the family Galaxiidae found in Australia, New Zealand, and nearby islands. The name climbing galaxias is used in Australia, and koaro or kōaro in New Zealand. Further vernacular names include short-finned galaxias, broad-finned galaxias, Cox's mountain galaxias, and Pieman galaxias.

<span class="mw-page-title-main">Macquarie perch</span> Species of fish

The Macquarie perch is an Australian native freshwater fish of the Murray-Darling river system. It is a member of the family Percichthyidae and is closely related to the golden perch.

<span class="mw-page-title-main">Australian bass</span> Species of fish

The Australian bass is a small- to medium-sized species of primarily freshwater fish found in coastal rivers and streams along the east coast of Australia. A member of the genus Macquaria from the family Percichthyidae, the Australian bass is an important member of the native fish assemblages found in east coast river systems. It is a native predatory fish and an extremely popular game fish species among anglers. The species was simply called perch in most coastal rivers where it was caught until the 1960s, when the name "Australian bass" started to gain popularity.

<i>Mountain galaxias</i> (species complex) Group of fishes

The mountain galaxias is a species complex of freshwater galaxiid fish found all over southeast Australia.

<span class="mw-page-title-main">Common galaxias</span> Species of fish

The common galaxias or inanga is a very widespread Southern Hemisphere fish in the family Galaxiidae. It is a slim, narrow fish with a forked tail and a mottled, spotty pattern, typically about 10 cm (4 in) long when fully grown. It lives in fresh water, but spawns at river mouths and spends the first six months of its life at sea, returning en masse in spring. Its vernacular names include cowfish, jollytail, common jollytail, eel gudgeon, inaka, native trout, pulangi, puye, slippery tarki, spotted minnow, Falklands minnow and whitebait.

<i>Galaxias olidus</i> Species of fish

Galaxias olidus, the mountain galaxias, is a species of freshwater galaxiid fish widely found in southeastern Australia.

<span class="mw-page-title-main">Eldon's galaxias</span> Species of fish

Eldon's galaxias is an endangered galaxiid fish endemic to New Zealand. One of several fishes in the genus Galaxias found in Central Otago, it has a very small home range and is at risk of being driven to extinction by trout introduced for recreational fishing.

<span class="mw-page-title-main">Common river galaxias</span> Species of fish

The common river galaxias or Canterbury galaxias is a galaxiid fish of the genus Galaxias, found only in Canterbury, New Zealand.

Gollum galaxias is a galaxiid of the genus Galaxias, found only in southern temperate regions in New Zealand. The species is widespread in rivers throughout the Southland Plains as well as the Von River and Nevis River tributaries of the Clutha River The species is found on Stewart Island/Rakiura, and throughout the Catlins.

<i>Galaxias</i> Genus of fishes

Galaxias is a genus of small freshwater fish in the family Galaxiidae, and are frequently referred to as the galaxiids. These highly adaptable fish are typically found at temperate latitudes across the Southern Hemisphere.

<i>Galaxias fontanus</i> Species of fish endemic to Tasmania, Australia

Galaxias fontanus, the Swan galaxias, is a species of fish in the family Galaxiidae. It is endemic to eastern Tasmania, Australia.

<span class="mw-page-title-main">Golden galaxias</span>

The Golden galaxias is an endangered species of landlocked galaxiid fish belonging to the genus Galaxias. It is endemic to Lakes Crescent, Sorell, and their associated waterways located in central Tasmania, Australia.

<i>Arripis truttacea</i> Species of marine ray-finned fish

Arripis truttacea, the Western Australian salmon, is a species of marine ray-finned fish within the genus Arripis, the only genus within the family Arripidae. It is endemic to the seas off southern Australia.

References

References

  1. 1 2 Morgan, D.L.; Beatty, S. (2019). "Galaxias truttaceus". IUCN Red List of Threatened Species . 2019: e.T122903281A123382171. doi: 10.2305/IUCN.UK.2019-3.RLTS.T122903281A123382171.en . Retrieved 30 April 2022.
  2. Humphries, Paul (1989). "Variation in the life History of Diadromous and Lanlocked populations of the Spotted Galaxias, Galoxias truttaceus Valenciennes, in Tasmania". Australian Journal of Marine and Freshwater Research. 40 (5): 201–518.