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Native Fish St ate y

FISH FACTSHEET:

DISTrIbuTIoN AND AbuNDANCEThe Common galaxias is a common shof lowland coastal streams, from SA to

southern Qld and Tas. In the Murray-Darling Basin it is known from the LowerLakes (Alexandrina and Albert), extendingup to approximately Mannum on theLower Murray and streams of the Mt LoftyRanges in SA. Its abundance in the lowerBasin is likely to have been affected bythe barrages below the Lower Lakes ,which act as a barrier to prevent the larvalwhitebait stage returning from the sea.However, the species is still widespread andabundant in the Lower Lakes , where it maybe recruiting as a landlocked populationwithout access to marine environments. It isalso known from the Wimmera, Loddon andCampaspe catchments in Vic, where it isconsidered a translocated species, probablyintroduced through water diversions fromcoastal streams or in bait-buckets.

Scientifc Name

Galaxias maculatus (Jenyns, 1842) photo by Gunther Schmida

CommoN gAlAxIAS(CommoN joll TAIl)

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Murray-Darling Basin AuthorityGPO Box 1801 Canberra ACT 2601

Tel 02 6279 0100 Fax 02 6248 8053

www.mdba.gov.au

First published - January 2009

IDENTIFICATIoNA small, slender sh with a slender caudal peduncle.Maximum size 190mm; usually < 100mm. Scales areabsent, the tail is slightly forked, and the anal n originatesdirectly below the dorsal n. The head is small and bluntlypointed and the mouth is small, only reaching back to thefront of the eyes. The jaws are equal in length. Overalltranslucent grey-olive to amber in colour, with the backand sides irregularly blotched or spotted greenish grey. Thebelly, eyes and gill covers are bright silvery to white. The nsare largely translucent.

bIolog AND HAbITATThis species is commonly found in coastal habitats, in still

or slow- owing streams and the margins of lagoons andlakes. Coastal stream populations breed in autumn, withadults migrating downstream to brackish areas to spawn.The larvae disperse to sea for six months before returningto streams the following spring. In landlocked populationsin lakes, breeding occurs in late winter-early spring onrising water levels, with adults making a short migrationinto tributaries to spawn. The larvae are washed downinto lakes to spend several months amongst the shallowshoreline vegetation. Individuals are mature at the end oftheir rst year, (~ 90mm length), although some do notbreed until their second year. Very few survive until the endof their third year and a substantial proportion of adult shdie after spawning. Each female produces several thousandeggs (up to 13,500). The spawning site is in terrestrialvegetation above the normal water line, either in oodedshallow margins of streams or above the normal tideline inestuaries. The adhesive eggs (~ 1mm diameter) develop inthese moist environments over about 14 days and hatchingis stimulated by the next high tide or ood. Eggs are able tosurvive without immersion for up to 8 weeks. Newly hatchedlarvae are approximately 7mm long.

The species is carnivorous and takes food from thebottom, mid-water or the surface. The diet of landlocked

populations consists mainly of amphipods, chironomidlarvae and microcrustaceans; stream-dwelling individualsconsume more insects.

PoTENTIAl THrEATSThe barrages on the Lower Lakes may be depressing larvalwhitebait returns and reduced ows may be reducingspawning opportunities for landlocked recruitment andmigration.

gENErAl rEFErENCES• Allen et al. 2002;

• Becker et al. 2005;

• McDowall & Fulton 1996;

• Pollard 1971, 1972, 1973;

• Stuart et al. 2005;

• Wedderburn & Hammer 2003.

PDF lINkSFishes of the Murray-Darling Basin: An introductory Guide;

http://mdba.gov.au/fles/publications/MDBA-Fish-species-book.pd