Pedder galaxias
The Pedder galaxias (Galaxias pedderensis) is a freshwater fish species native to Australia, officially declared extinct in the wild since 2005 under the EPBC Act. Its original habitat was limited to Lake Pedder in Tasmania.
Range
The species was originally restricted to Lake Pedder and its tributaries. Following the creation of the "new" Lake Pedder in 1972, caused by the Huon–Serpentine dam, its distribution extended into Lake Gordon and the Wedge River. However, by 1980, there was a significant reduction in population numbers, with no individuals recorded in natural environments after 1996. The introduction of trout has been a major contributor to this decline. Currently, the Pedder galaxias survives only through two relocated populations: one in Lake Oberon within the Western Arthurs and another in a modified water supply reservoir near Strathgordon.[1]
Description
This diminutive fish displays a greenish-brown coloration on its upper body, contrasted by a pale, silvery-white underside. Its pattern consists of alternating light and dark bands that extend into the fins and break into fine spots along the lower flanks. Individuals can reach lengths up to 160 mm.
Habitat
Prior to the construction of dams, the Pedder galaxias inhabited shallow areas of Lake Pedder characterized by white sandy shores, submerged aquatic plants, swamps, and slow-moving waters abundant with organic material and overhanging terrestrial vegetation.[2]
Its diet comprises small invertebrates including arthropods, larvae of aquatic insects, crustaceans, as well as terrestrial insects such as beetles, flies, and cicadas.[2]
Conservation status
- Recognized as extinct in the wild under the EPBC Act since 2005.
- Classified as endangered by the IUCN starting in 2019.
Reproduction
Females are generally larger than males. The male's genital papilla is slender, whereas females exhibit a broad and rounded papilla during breeding periods. Egg production ranges from 150 to 1,200 per female, with eggs measuring between 1.9 and 2.3 mm in diameter once hardened by water. Spawning takes place in spring (October) when water temperatures range from 6.7 to 7.5 °C.