7/27/2019 Spotted Galaxias

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Nati e Fish St ate y

FISH FACTSHEET:

CoNSErvATIoNS STATuSTranslocated or remnant?

DISTrIbuTIoN AND AbuNDANCENormally a species of coastal streams ofVic, Tas and southwest WA, in the Basin theSpotted galaxias is present in the upperCampaspe and Loddon drainages, whereit is thought to have been transferred fromcoastal Victorian streams through its use forbait, or to represent a remnant populationof a historically wider distribution. A singlerecent record of a whitebait of this speciesis also known from the Lower Murray near

Wentworth.

Scientifc Name

Galaxias truttaceus Valenciennes, 1846 photo by Gunther Schmida

SpoTTED gAlAxIAS(SpoTTED mouNTAIN TrouT, TrouT mINNow)

7/27/2019 Spotted Galaxias

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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 large, stout-bodied, scaleless sh with a longish head andlarge mouth reaching back to below the front of the eyes.Maximum size > 200mm; usually 120-140mm. The anal nis positioned directly below or slightly behind the dorsal n,and the tail is slightly forked. The dorsal, anal and caudalns are golden to orange, with a dark rear fringe. The backis a brownish to deep-olive, fading to brownish-grey on thesides and silvery on the belly. Large, round purplish spotsare present on the upper sides and back, each surroundedby a lighter halo. There is a distinct dark diagonal stripeextending down from the bottom of the eye.

bIolog AND HAbITAT

In its natural lowland coastal habitats, the Spotted galaxiasfavours cover such as logs, boulders and overhung banks onthe edges of pools. Coastal populations spawn in autumn-winter, and the larvae have a marine phase of severalmonths before returning to estuaries as 45-65mm whitebaitin spring. In landlocked populations spawning occurs inspring after an upstream migration into feeder streams,and the larvae ful lling their pelagic phase in downstreamlakes. Fecundity is moderate to high: 1000-16,000 eggsdeposited amongst instream aquatic vegetation. The eggsare small (~1.0-1.3mm diameter) and take about fourweeks to hatch, and the larvae are about 6.5-9.0mm longat hatching. Spotted galaxias are carnivorous-adults eataquatic insect larvae and terrestrial insects that fall ontothe water surface. They take much of their food in the driftin mid-water, particularly caddis ies and may ies. Thelarvae feed mainly on microcrustaceans (copepods) for therst 2-3 months of life. There are signi cant differences inthe ecology of the coastal and landlocked populations ofthis species in Tasmania, including different timing of thebreeding season and the presence of more young sh incoastal populations. There are also signi cant differencesbetween landlocked Tasmanian and landlocked WesternAustralian populations: the Tasmanian sh mature later,live longer, grow larger and have larger eggs and larvae.

The WA population has the late-autumn spawning seasonof the coastal Tasmanian sh. Little is known of thespecies’ ecology in the Basin, but it must be assumedthat the Basin populations are landlocked given the largenumbers of migration barriers between the Campaspeand marine waters.

poTENTIAl THrEATSPredation and displacement by introduced trout species,and habitat loss through deforestation are threats. Whentranslocated, the Spotted galaxias may itself pose a threatto other native sh species through competition for foodor space.

gENErAl rEFErENCES• Allen et al . 2002;

• Cadwallader & Backhouse 1983;

• McDowall & Fulton 1996;

• Gilligan 2005b;

• Humphries 1989, 1990;

• Humphries & Lake 2000;

• Littlejohn 2000; Morgan 2003.

• Morgan 2003.

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

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