Download Barred galaxias - Murray-Darling Basin Authority

NATIVE SPECIES
Common Name
Barred galaxias
Scientific Name
Galaxias fuscus Mack, 1936
Photo: Gunther Schmida
Threatened
Identification
A small and, strikingly coloured fish.
Maximum size 160 mm; commonly 70–90
mm. Scales are absent, the tail is truncate to
weakly forked, and the anal fin originates
behind the middle of the dorsal fin. The head
is short and bulbous and the caudal peduncle
is thick compared to that of the Mountain
galaxias. The body is an unmottled orangeyellow colour with 1–10 complete or partial
vertical ovoid black bars on the sides between
the gill cover and just behind the origin of the
pelvic fin.
Biology and Habitat
The Barred galaxias occurs in cool, clear,
upland streams with stony or sandy substrates.
Little is known of its ecology due to its
highly threatened status and small population
size. The preferred habitat is thought to be
slow-flowing deep pools adjacent to riffles
and cascades. Spawning is triggered by an
increase in day-length and water temperature
in August–September. Average fecundity
is about 500 eggs, which are large (unshed
40
eggs are ~ 2.2 mm diameter) and demersal.
The eggs are laid under large boulders when
water temperatures are around 2–3° C. Time
to hatching and size of larvae at hatching
are unknown, but 12 mm long larvae are
present in streams by December. Movement
requirements are unknown, but the species is
thought to be non-migratory and relatively
sedentary, judging by recolonisation rates of
streams where trout have been removed.
The diet consists of drifting and benthic
aquatic invertebrates taken at the upstream
end of pools. The species is relatively longlived for a small fish—individuals up to 13
years old have been recorded.
Distribution and Abundance
The Barred galaxias is only found in the
headwaters (above 400 m altitude) of the
Goulburn River catchment in the central
highlands of Vic, in the southern MurrayDarling Basin. There are approximately 20
known populations of this species still extant,
and at least five previous populations are now
extinct. It is possible that additional small
F i s h e s o f t h e M u r r ay- D a r l i n g B a s i n
ID Valley
1 Avoca
2 Border Rivers
3 Broken
4Campaspe
5Castlereagh
6Central Murray
7Condamine
8Darling
9Goulburn
10Gwydir
11 Kiewa
12 Lachlan
13 Loddon
14 Lower Murray
15 Macquarie
16 Mitta Mitta
17 Murrumbidgee
18Namoi
19Ovens
20 Paroo
21Upper Murray
22 Warrego
23 Wimmera
populations may be discovered in inaccessible
areas of the upper Goulburn catchment, but
this is unlikely to affect the highly threatened
status of the species.
Potential Threats
Interaction with Rainbow and Brown trout
(largely predation) is the major threat to the
Barred galaxias. Following the invasion of
trout, the species has been eliminated from
streams where it was formerly abundant.
It has been recorded in gut samples of
trout captured in Barred galaxias habitat,
and juvenile galaxias are the most severely
impacted by predation. Competition between
larger Barred galaxias and trout may be a
secondary threat. As a result of the small,
fragmented distribution of the species, local
habitat modifications and degradation could
also threaten populations. The effects of
the invading Climbing galaxias on natural
galaxiid populations are unknown, but
competition or displacement is possible.
upstream invasion by trout an essential part of
their management.
General References
Allen et al. 2002; DSE 2006; Lintermans
& Raadik 2003; Morris et al. 2001; Raadik
1995a, 2000; Raadik et al. 1996; Shirley &
Raadik 1997.
Barred galaxias now exist only in trout-free
streams, with physical barriers to exclude
An introductory guide
41
Published by the Murray-Darling Basin Commission
Postal address: GPO Box 409, Canberra ACT 2601
Office location: Level 3, 51 Allara Street, Canberra City ACT
Telephone: (02) 6279 0100, international + 61 2 6279 0100
Facsimile: (02) 6248 8053, international + 61 2 6248 8053
Email: [email protected]
Internet: http://www.mdbc.gov.au
For further information contact the Murray-Darling Basin Commission office on
(02) 6279 0100
This fish fact sheet is an extract derived from the report:
Lintermans, M. 2007, Fishes of the Murray-Darling Basin: An introductory guide.
MDBC Publication No. 10/07
ISBN 1 921257 20 2
© Murray-Darling Basin Commission 2007
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(Fishes of the Murray-Darling Basin) is acknowledged. Such reproduction includes fair dealing
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exclude all liability to any person for any consequences, including but not limited to all losses,
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F i s h e s o f t h e M u r r ay- D a r l i n g B a s i n