Australian trout pike
| Australian trout pike | ||||||||||||
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A relatively small Australian trout pike |
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| Scientific name | ||||||||||||
| Prototroctes maraena | ||||||||||||
| Günther , 1864 |
The Australian trout pike ( Prototroctes maraena ) is a bony fish species described by Albert Günther in 1864 from the genus of trout pike ( Prototroctes ) within the New Zealand salmon family (Retropinnidae).
features
The Australian trout pike can reach a standard length of more than 30 cm, but today rarely exceeds 25 cm. It is dark brown to olive green on the back, greenish-bronze colored on the sides, occasionally with a steel blue shimmer. The gill covers are silver, the belly and the underside of the head are silver-white to yellowish. The fins are transparent to grayish or straw-colored. The dorsal fin sits above the pelvic fins, an adipose fin is present. The maxillary is toothless and the lower jaw is surrounded by a horny rim. The number of vertebrae is 62 to 72.
The Australian trout pike smells of cucumber. Most animals live to be two to three years old, some up to five years old.
distribution
Occurrences of the Australian trout pike are known in southeast Australia, from the Grose River in the east of the state of New South Wales to the Hopkins River (state of Victoria ). It is also found in Tasmania and on King Island at the western end of Bass Strait .
Habitat and way of life
The Australian trout pike is an amphidromic species that lives in the upper reaches of clear, moderately to fast flowing rivers. Sometimes it can be found at altitudes above 1000 m. It spawns in rivers near the coast, the spawning season in Australian autumn varies depending on the river and environmental influences. A female can lay approximately 47,000 eggs. The demersal (sinking to the bottom), non-adherent eggs have a diameter of 0.9 mm. The fish larvae are washed into the sea from the rivers, where the young Australian trout pike reside for the first 6 months of their lives, after which they return to the rivers, where they spend the rest of their lives. The Australian trout pike feeds on algae and aquatic insects. With the comb-like jaw teeth, insects can be ingested by thread algae, the black peritoneum could come from vegetable parts in the diet.
Danger
A mass extinction of Australian trout pike was reported in the 1880s, coinciding with the introduction of trout into Tasmania . In 1888, Saville-Kent hinted that a fatal disease was brought in with the trout and reported that dead and dying animals were seen:
"Drifting down the rivers by the thousands, covered ... with a cotton wool-like fungus infestation"
Today, the Australian trout pike are threatened in many ways. On the one hand by dams and weirs that hinder the migrations to the sea and back, on which the species depends. Clearing leads to silting up and deterioration of the water quality. Introduced trout species threaten the species by being displaced.
The Australian trout pike is listed under the endangered species under Australia's Environment Protection and Biodiversity Conservation Act 1999 with the status "vulnerable" (vulnerable) . The International Union for Conservation of Nature and Natural Resources (IUCN) classifies the species as low endangered, as it is dependent on protective measures, using an early warning list (Near Threatened, NT).
Individual evidence
- ^ A b c Tim M. Berra : Freshwater Fish Distribution. University of Chicago Press, 2007, ISBN 978-0226044422 , pp. 261-262.
- ^ Australian Government - Department of Sustainability, Environment, Water, Population and Communities: Prototroctes maraena - Australian Grayling
- ^ Joseph S. Nelson, Fishes of the World , John Wiley & Sons, 2006, ISBN 978-0471250319 , p. 196.
- ↑ a b c Prototroctes maraena in the IUCN Red List of Threatened Species 2011.2. Posted by: A. Jenkins, FF Kullander, HH Tan, 2009. Retrieved March 17, 2012.
- ↑ G. Backhouse, J. Jackson, J. O'Connor: National Recovery Plan for the Australian Grayling Prototroctes maraena. 2008, Department of Sustainability and Environment, Melbourne, p. 7. ( Online ( Memento from March 22, 2012 in the Internet Archive ); PDF; 694 kB)
- ↑ Guidelines for detecting fish listed as threatened under the Environment Protection and Biodiversity Conservation Act 1999. ( Online ( Memento of March 19, 2012 in the Internet Archive ); PDF; 602 kB)
Web links
- Australian trout pike on Fishbase.org (English)