Redfin blue-eye
| Redfin blue-eye | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Scaturiginichthys | ||||||||||||
| Ivantsoff , Unmack , Saeed & Crowley , 1991 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Scaturiginichthys vermeilipinnis | ||||||||||||
| Ivantsoff, Unmack, Saeed, Crowley, 1991 |
The redfin blue-eye ( Scaturiginichthys vermeilipinnis ) (Latin scaturex = gushing spring water; French vermeil = rosy; Latin pinna = fin), from the blue-eye family, is the smallest freshwater fish in Australia. The species is endangered. It was discovered in 1990 in arid Central West Queensland , where it only lives in a few very shallow artesian- fed springs.
features
This predominantly silvery-transparent blue-eye species with a translucent swim bladder reaches a maximum body length of only about 2.5 cm. The mouth is relatively large compared to the body size. The eyes are silvery blue. The unpaired fins and the pelvic fins of the males are red-edged. The males are also, as is typical for blue eyes, somewhat larger and have longer fins than the females.
In contrast to other blue eyes, the external morphology of Scaturiginichthys vermeilipinnis has the following peculiarities:
- a short, rounded caudal fin,
- a deeper approach to the pectoral fins as well
- reduced ventral fins: from four fin rays to a complete lack of one or both sides (possibly an adaptation to the very shallow waters).
Occurrence and habitat
The redfin blue-eye is the only blue-eye found inland. It is endemic to some of the spring ponds ( Edgbaston Springs ) at Aramac , Barcaldine Region . The springs, actually only a few centimeters shallow, larger puddles, lie in the catchment area of the Thomson River river system, which only carries water periodically . The area is very dry and open, the spring ponds are overgrown with tussock . The 44 or so springs, 30 of which are permanently water-bearing, extend over a small area of a total of 6 to 8 square kilometers on a flat alluvial plain. The temperatures and water values fluctuate considerably in the desert-like climate not only with the time of year and day, but also within a spring pond. The spring ponds in which the redfin blue-eye occurs are usually alkaline and clear, with pH values between 7.8 and 8.0. The fish stay in areas where the water temperature is above 16 ° C.
Way of life
The fish were found in all areas of the spring pond. Adult fish usually stay in the slightly deeper areas, while juvenile fish are found in shallow areas. When disturbed, they briefly form large swarms, which then split up into small groups to eat and court.
Details of the reproduction are known from aquarium observations in the 1990s. Wild-caught animals could easily be reared, while the first generation of offspring could hardly be reproduced. Reproduction succeeds at temperatures between 20 and 32 ° C with frequent feeding with live food such as mosquito larvae. The females then lay an average of three to five eggs about 1.5 mm in size every day, which the adult fish will pursue even if they are well fed. After a development of one to two weeks, the 4 to 5 mm long fish larvae hatch, after about half a year with a length of 1.5 cm the young fish become sexually mature.
Danger
The Edgbaston Springs used to be managed as a sheep and cattle farm. Because of the highly endemic aquafauna, the area was bought up in 2008 by the private conservation organization Bush Heritage Australia as the Edgbaston Reserve with the help of the Australian government .
Scaturiginichthys vermeilipinnis is considered Australia's most threatened freshwater fish. Estimates of the population range from a few hundred to three thousand individuals. When they were discovered by Peter Unmack in 1990, the fish were found in eight separate spring ponds. Since then five populations have died out, but two spring ponds have been repopulated by the remaining populations. In a study in 2005, red-fin blue-eyes were only found in five relatively small and very shallow spring ponds; in 2009 they were only found in four. The species was included in the list of the world's 100 most endangered animal, plant and fungus species at the IUCN World Conservation Congress in September 2012 .
The greatest acute threats are wild pigs in the area, which are destroying the habitat, and the viviparous mosquito fish Gambusia holbrooki , which was introduced by humans and was found in many spring ponds when the redfin blue-eye was discovered in 1990, colonized at least 21 of the spring ponds in 2009 and the original aquafauna in the Sources displaced. Due to flooding, there is a risk that other ponds will be colonized by the exotic species. Current measures include the targeted resettlement of redfin blue-eyed in safer source ponds, the removal of mosquito fish from the most important source ponds and their sealing against floods.
In the long term, there is a risk of complete drying out of Edgbaston Springs due to the intensive extraction of groundwater in the entire Great Artesian Basin .
literature
- G. Allen, S. Midgley, M. Allen: Field Guide to the Freshwater Fishes of Australia . 2nd Edition. Western Australian Museum, Perth 2003, ISBN 0-7307-5486-3 , pp. 170 .
- Hans J. Mayland: blue eyes and rainbow fish . Dähne, Ettlingen 2000, ISBN 3-921684-82-X , p. 74-75 .
- W. Ivantsoff, P. Unmack, B. Saeed, L. Crowley: A red-finned blue-eye, a new species and genus of the family Pseudomugilidae from central western Queensland . In: Fishes of Sahul . tape 6 , no. 4 , 1991, ISSN 0813-3778 , pp. 277-282 . (first scientific description)
Web links
- Redfin blue-eye on Fishbase.org (English)
- Adrian R. Tappin: Scaturiginichthys. (English). Photos, species and biotope description.
- Scaturiginichthys vermeilipinnis inthe IUCN Red List of Threatened Species 2013.2. Posted by: Wager, R., 1996. Retrieved January 11, 2014.
Individual evidence
- ↑ Edgbaston Reserve at www.bushheritage.org.au (accessed September 13, 2012)
- ↑ Bush Heritage Australia embark on project to save world's last population of fish species . (PDF 109 kB) Bush Heritage Australia , June 10, 2009, archived from the original on March 22, 2012 ; accessed on May 11, 2019 (English, original website no longer available).
- ↑ Australia's rarest fish has been listed among the world's most 100 endangered species . Bush Heritage Australia , September 12, 2012, archived from the original on April 1, 2015 ; accessed on May 11, 2019 (English, original website no longer available).