Spawning of Threatened Barred Galaxias, Galaxias fuscus (Teleostei: Galaxiidae)

Daniel J Stoessel, Tarmo A Raadik, Renae M Ayres

Abstract


Barred galaxias Galaxias fuscus is an endangered freshwater fish endemic to south-eastern Australia. Little is known of the species’ ecology. We investigated spawning biology of G. fuscus in three headwater streams and found spawning to occur mid-August to late September when photoperiod was 10 h 39 min – 12 h 25 min. Spawning sites were in fresh (range 35.3 – 56.6 EC, mean 44.7 EC), slightly acidic (range 5.7 – 7.1 pH, mean 5.9 pH), moderate to fast flowing (range 0.4 – 2.0 m/s, mean 1.0 m/s), shallow (range 70 – 310 mm, mean 174 mm), well oxygenated (range 10.8 – 12.4 mg/l, mean 11.3mg/l), clear (range 1.2 – 6.3 NTU, mean 3.8 NTU), cool waters (range 8.4 – 10 °C, mean 9.1°C) immediately upstream of pools. Multi-layered clusters of up to 218 eggs were generally adhered close to the stream bed on the downstream side of cobbles greater than 180 mm diameter.

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