Climbing galaxias

The climbing galaxias or koaro (Galaxias brevipinnis) 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.

Kōaro or climbing galaxias
Juvenile koaro, photo by Stella McQueen
Juvenile kōaro
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Osmeriformes
Family: Galaxiidae
Genus: Galaxias
Species:
G. brevipinnis
Binomial name
Galaxias brevipinnis
Günther, 1866

Appearance

Adult koaro (Galaxias brevipinnis) from the Momona Stream, Taranaki. Photo by Stella McQueen
Adult koaro (Galaxias brevipinnis)

The climbing galaxias is unlikely to be confused with the other diadromous whitebait species because of its shape. It is elongated and slender, shaped almost like a tube. The sides and back are covered in a variable pattern of golden blotches and bands that gleam and glitter in the sun, making the climbing galaxias an attractive fish.

The maximum size is around 28 cm, but it is commonly found to 15 cm.[2]

Lifestyle

These fish live a basically benthic lifestyle and in most respects behave like the common galaxias, a closely related galaxiid. They inhabit mainly clear streams, often deeply shaded and relatively fast-flowing, although they sometimes occur in lakes, particularly in Tasmania. Climbing galaxias also have the ability to penetrate well inland in many river systems, thus have a more widespread distribution than the other whitebait species.

A major distinguishing feature of this species is its ability to climb up very steep surfaces such as waterfalls, wet rocks, and the sluices of dams using its broad and downward facing pectoral and pelvic fins.[2] Even juveniles of the species are capable of climbing up and over the sides of buckets after being trapped in whitebait nets.

Climbing ability is not unique among galaxias species, but it reaches its greatest expression in the climbing galaxias, which have special features that enhance their climbing abilities. The downward orientation of their fins and the strong, backward-facing ridges on the front part of their fins possibly contribute to this ability.

Climbing Galaxias once formed large populations in some lakes. It once roamed New Zealand's Lake Taupo in huge shoals and was caught in huge numbers by Maori people using specialized nets. Introduced rainbow trout has now virtually eradicated the species from Lake Taupo.[3] Similarly, the introduction of brown trout eradicated a climbing galaxias population from Lake Tarli Karng in Victoria, Australia (Cadwallader, 1996).

Lifecycle

G. brevipinnis eggs are believed to be washed downstream to the sea, where the young live for about six months before returning to fresh water as part of the large, mixed-species schools known as whitebait. They were once part of a commercial whitebait fishery in Tasmania, but now fishing for them has been restricted to recreational anglers with significant restrictions on allowable tackle and methods. Land-locked populations have a similar lifestyle except the young spend the first part of their lives in inland lakes and backwaters.

Diet

These fish are generalised carnivores of invertebrates, including aquatic and terrestrial insects, mayfly and caddisfly larvae, and amphipods.

Distribution

Their distribution extends to coastal streams in southeastern Australia from Adelaide and Kangaroo Island in South Australia, through coastal Victoria including Wilsons Promontory, Tasmania, Flinders and King Islands, and north along the New South Wales coast to around Sydney, as well as New Zealand including the Chatham, Auckland and Campbell Islands.

Their climbing ability enables them to inhabit headwaters of streams that introduced species, such as trout, cannot reach.[2]

Koaro are known to breed in Nelson, New Zealand. Eggs have been found upstream of baffles installed in Brook Stream to assist fish passage; a Project Maitai initiative.

References

  1. ^ "Galaxias brevipinnis". IUCN Redlist. Retrieved 8 August 2015.
  2. ^ a b c Gomon, Martin; Bray, Dianne. "Climbing Galaxias, Galaxias brevipinnis". Fishes of Australia. Retrieved 30 August 2014.
  3. ^ "NEW ZEALAND ECOLOGY—NATIVE GALAXIID FISH—KOARO". TerraNature. Retrieved 28 November 2017.

External links

Auckland Islands

The Auckland Islands (Māori: Motu Maha or Maungahuka) are an archipelago of New Zealand, lying 465 kilometres (290 mi) south of the South Island. The main Auckland Island, occupying 510 km2 (200 sq mi), is surrounded by smaller Adams Island, Enderby Island, Disappointment Island, Ewing Island, Rose Island, Dundas Island, and Green Island, with a combined area of 625 km2 (240 sq mi). The islands have no permanent human inhabitants.

The islands are listed with the New Zealand Outlying Islands. The islands are an immediate part of New Zealand, but not part of any region or district, but instead Area Outside Territorial Authority, like all the other outlying islands except the Solander Islands.

Ecologically, the Auckland Islands form part of the Antipodes Subantarctic Islands tundra ecoregion. Along with other New Zealand Sub-Antarctic Islands, they were designated a UNESCO World Heritage Site in 1998.

Cleland Conservation Park

Cleland Conservation Park is a protected area located in the Adelaide Hills, South Australia about 22 kilometres (14 mi) south-east of the Adelaide city centre. Cleland Conservation Park conserves a significant area of natural bushland on the Adelaide Hills face and includes the internationally popular Cleland Wildlife Park and the popular tourist destinations of Mount Lofty summit and Waterfall Gully. It is maintained by the South Australian Department of Environment, Water and Natural Resources (DEWNR).The conservation park was named for Sir John Burton Cleland (1878-1971), a renowned naturalist, microbiologist, mycologist and ornithologist, and member of the Royal Society of South Australia. After a career in medicine and pathology, Cleland became keenly interested in wildlife conservation.The conservation park occupies land in the gazetted suburbs of Cleland, Crafers and Waterfall Gully.The conservation park is classified as an IUCN Category II protected area.

Dharawal National Park

The Dharawal National Park is a protected national park that is located in the Illawarra region of New South Wales, in eastern Australia. The 6,508-hectare (16,080-acre) national park is situated between the Illawarra Range and the Georges River and is approximately 45 kilometres (28 mi) south west of Sydney. There are three entry points to the park: from the east through Helensburgh; from the north through Campbelltown; and from the south through Appin.The national park covers almost both the O’Hares and Stokes Creek catchments. It contains significant biodiversity and ecosystems as well as Aboriginal culturally significant sites. It has high conservation significance within the region, especially due to the low disturbance within the park and limited public access. The landscape varies from gorges and waterfalls to upland swamps to sandstone woodland, rainforests, and eastern gully forests. The residents of the park include koalas, wallabies, wallaroos, platypuses, potoroos, pygmy possums and many more animal species.

The conservation objectives of the park are to maintain the natural and cultural heritage, provide education and research opportunities as well as providing some recreation activities.

Fish in Australia

Australia has over 5000 described species of fish, a quarter of which are endemic. Seafood and aquaculture are major and highly regulated industries, and fishing for marine and freshwater native and stoked fish is popular.

Galaxias

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

Galaxiids are scaleless and somewhat tubular in body form, ranging from very slender to quite bulky. They are somewhat torpedo-shaped, with the dorsal and anal fins positioned close to the tail. They are generally small, with typical adult lengths ranging between 4–15 cm (1.6–5.9 in) in total length, with some stocky species attaining around 25 cm (10 in). The largest, Galaxias argenteus, has been recorded at 58 cm (1.90 ft), although 30–40 cm (12–16 in) is a more typical adult length.

Galaxiidae

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 (Galaxias maculatus), 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.

Some galaxiids live in fresh water all their lives, but many have a partially marine lifecycle. In these cases, larvae are hatched in a river, but are washed downstream to the ocean, later returning to rivers as juveniles to complete their development to full adulthood. This pattern differs from that of salmon, which only return to fresh water to breed, and is described as amphidromous.Freshwater galaxiid species are gravely threatened by exotic salmonid species, particularly trout species, which prey upon galaxiids and compete with them for food. Exotic salmonids have been recklessly introduced to many different land masses (e.g. Australia, New Zealand), with no thought as to impacts on native fish, or attempts to preserve salmonid-free habitats for them. Numerous localised extinctions of galaxiid species have been caused by the introduction of exotic salmonids, and a number of freshwater galaxiid species are threatened with overall extinction by exotic salmonids.

Lake Disappear

Lake Disappear is an intermittent lake (see also Turlough (lake) and Polje) situated in the North Island of New Zealand, just over 20 km from Raglan, 4 km beyond Bridal Veil waterfall. It has also been described as a solution lake. The south end can be seen from Kawhia Rd and, when the north end is full, it can be seen from the point which is at the end of Plateau Rd on the Pipiwharauroa Way. It is the largest known polje in the country.

List of least concern fishes

As of September 2016, the International Union for Conservation of Nature (IUCN) lists 9131 least concern fish species. 60% of all evaluated fish species are listed as least concern.

The IUCN also lists 37 fish subspecies as least concern.

Of the subpopulations of fishes evaluated by the IUCN, 44 species subpopulations have been assessed as least concern.

This is a complete list of least concern fish species and subspecies evaluated by the IUCN. Species and subspecies which have least concern subpopulations (or stocks) are indicated.

Manly Dam Reserve

The Manly Dam Reserve, also known as the Manly Warringah War Memorial Park, is an nature reserve of protected urban bushland located in the Northern Beaches region of Sydney, Australia. Located among the suburbs of Allambie Heights, North Balgowlah, Frenchs Forest and Manly Vale in the Northern Beaches Council local government area. The reserve adjoins the south-eastern edge of Garigal National Park.

Located within the 376-hectare (930-acre) reserve is the 30-hectare (74-acre) Manly Dam, an heritage-listed former reservoir near King Street, Manly Vale. The dam was designed by the NSW Department of Public Works and built in 1892 by the Department. The dam is owned by Sydney Water, an agency of the Government of New South Wales. The dam was added to the New South Wales State Heritage Register on 18 November 1999.The Northern Beaches area has long been recognised as being part of the traditional lands of the Kuringgai people. There are a number of Aboriginal heritage sites found within the reserve.

New Zealand freshwater mussel

The New Zealand freshwater mussel (Echyridella menziesii), also known by its Māori names kākahi, kāeo, and torewai, is a species of freshwater mussel endemic to New Zealand. E. menziesii is an aquatic bivalve mollusc in the family Unionidae, the river mussels.

They were an important food source for the Māori, but like many freshwater mussels worldwide, are now endangered by pollution and eutrophication of rivers, and the introduction of new species of fish leading to actions via the Treaty of Waitangi claims process.

Rowallan Power Station

The Rowallan Power Station is a conventional hydroelectric power station located in north-western Tasmania, Australia. The station is located 25 kilometres (16 mi) south of Liena.

Trout

Trout is the common name for a number of species of freshwater fish belonging to the genera Oncorhynchus, Salmo and Salvelinus, all of the subfamily Salmoninae of the family Salmonidae. The word trout is also used as part of the name of some non-salmonid fish such as Cynoscion nebulosus, the spotted seatrout or speckled trout.

Trout are closely related to salmon and char (or charr): species termed salmon and char occur in the same genera as do fish (Oncorhynchus – Pacific salmon and trout, Salmo – Atlantic salmon and various trout, Salvelinus – char and trout).

Lake trout and most other trout live in freshwater lakes and rivers exclusively, while there are others, such as the steelhead, which can spend two or three years at sea before returning to fresh water to spawn (a habit more typical of salmon). Steelhead that live out their lives in fresh water are called rainbow trout. Arctic char and brook trout are part of the char family. Trout are an important food source for humans and wildlife, including brown bears, birds of prey such as eagles, and other animals. They are classified as oily fish.

Whitebait

Whitebait is a collective term for the immature fry of fish, typically between 1 and 2 inches (25 and 50 mm) long. Such young fish often travel together in schools along the coast, and move into estuaries and sometimes up rivers where they can be easily caught with fine meshed fishing nets. Whitebaiting is the activity of catching whitebait.

Whitebait are tender and edible, and can be regarded as a delicacy. The entire fish is eaten including head, fins, bones, and guts. Some species make better eating than others, and the particular species that are marketed as "whitebait" varies in different parts of the world.

As whitebait consists of immature fry of many important food species (such as herring, sprat, sardines, mackerel, bass and many others) it is not an ecologically viable foodstuff and in several countries strict controls on harvesting exist.

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