Redfin blue eye
Common name: redfin blue eye
Scientific name: Scaturiginichthys vermeilipinnis
Conservation status: This species is listed as Endangered, both in Queensland (Nature Conservation Act 1992) and nationally (Environment Protection and Biodiversity Conservation Act 1999). It is ranked as a critical priority under the Department of Environment and Heritage Protection (EHP) Back on Track species prioritisation framework.
The redfin blue eye is a small Pseudomugilid fish that grows to a total length of 30 mm. The scientific name is a reference to the unique habitat (scaturginis is latin for bubbling spring or full of springs; ichthys is a latin word relating to fish), and the red colouration on the margins of the dorsal and anal fins (vermeil is old French for red or vermilion; pinnis is latin for fins). At present this is the only species in the genus and the only genus in the sub-family Scaturiginichthyinae.
Adult redfin blue eye are semi-transparent and their head and abdomen is silver. The margins of fins on the males are red (vermilion). Both sexes have a sky blue ring round each eye.
Habitat and distribution
Redfin blue eyes are endemic to Queensland and are known only from springs in the Edgbaston Spring Complex near Aramac. Monitoring in April 2005 found redfin blue eyes in a total of five springs. The species may have once occurred in artesian springs throughout the Lake Eyre Drainage Division. Estimating the population size of redfin blue eye is difficult due to the movement of fishes. In April 2005 the total population was estimated at no more than 3000 individuals.
In the Edgbaston Spring Complex, redfin blue eyes are found in clear shallow spring-fed pools, with the depth ranging from approximately 50-75 mm. These pools are clear and well oxygenated, with grasses and other plants growing throughout the springs. Water temperatures are extremely variable. In May 1990 the temperatures varied from 7-28°C, and water temperatures as high as 36°C have been recorded.
Life History and behaviour
Adult redfin blue eye occur in depths greater than 10-15 mm, while newly hatched fry and juveniles (less than 12 mm total length) are generally found in shallower water.
When approached, redfin blue eyes form loose schools of up to several hundred individuals. It is possible that this schooling behaviour is a predator avoidance response. If undisturbed the schools disperse into smaller groups, which begin feeding and displaying.
Mature males defend a 'personal space'. Males display at any females encountered within this personal space. Courtship displays are of variable duration and involve a male swimming around a female with outspread fins. Pairs align side by side and the male can be observed shimmying - probably at the time of egg release and fertilisation. Eggs are released over a substrate or onto submerged vegetation. Displays are observed in all months and are more frequent in the mornings and early afternoons. Newly hatched fry are observed in all months but more commonly during warmer months.
The diet of redfin blue eyes has not been studied in depth. It is suspected that they are facultative omnivores, meaning they eat whatever is available.
Major threats to the redfin blue eye are:
- land degradation by domestic stock and feral animals, in particular feral pigs
- competition with mosquito fish Gambusia holbrooki
- physical alteration of the springs to increase the volume of water for stock
- ponded pasture weed species that reduce habitat area and quality
- water extraction that diminishes spring flow.
- fence certain springs with pig-proof fencing, and provide alternative water sources for stock
- control mosquito fish Gambusia holbrooki to prevent competition
- eradicate ponded pasture weed species from the springs
- control all bores affecting groundwater flows to the springs
- monitor existing population numbers and study the biology and ecology of the species
- monitor groundwater flows to the springs
Fensham, RJ, Ponder, WF and Fairfax, RJ 2010 Recovery plan for the community of native species dependent on natural discharge of groundwater from the Great Artesian Basin Report to the Department of the Environment, Water Heritage and the Arts, Canberra. Queensland Department of Environment and Resource Management, Brisbane.