Download Fact sheet - Natural Resources South Australia

FRESHWATER FISH
Nannoperca australis
AUS
SA
AMLR
Endemism
-
-
E
-
Photo: © Michael Hammer
Conservation Significance
The AMLR distribution is part of a limited extant
distribution in adjacent regions within SA.2
Recommended for listing as Rare under NPW Act as
part of the threatened species status review in 2003.1
Under the SA Fisheries Act 2007 its status is Protected.
Description
Small, deep bodied species to 10 cm (commonly 3-5
cm), with a large eye and brilliant red fins during
spawning (males). Distinguished from Yarra Pygmy
Perch by a larger mouth reaching below the eye and
a regular (round) eye pupil; from Variegated Pygmy
Perch by having scales on top of the head and the
second dorsal spine longer than the third, and from
Chanda Perch by having a rounded rather than
forked tail.3
Recent genetic studies identified that ‘Southern
Pygmy Perch’ comprises two distinct species with an
eastern species in Gippsland (VIC), Flinders Island
and north-east TAS, and a western species occurring
coastally west of Wilsons Promontory and in the MDB.
The western species has two distinct genetic lineages
divided by the Great Dividing Range (i.e. coastal and
Murray-Darling) that warrant recognition at the
subspecies level. Hence there are two distinct units of
management in SA, (a) Murray lineage and (b) SE
lineage.3
Distribution and Population
In the SE region suitable habitat is much reduced due
to extensive drainage and there are presumed local
Southern Pygmy Perch
extinctions. The range and area of occupancy of the
Murray-Darling lineage continues to decline. Genetic
evaluation of the populations of the Murray lineage
indicates five genetically distinct sub-populations that
are separated by land barriers of 10km or less. The
remaining populations include:

patchy distribution in swampy edges and drains
around Lake Alexandrina, with core populations
on eastern Hindmarsh Island, Black Swamp and
near Milang (presumed extinct along the River
Murray itself; some local declines in Lake
Alexandrina), and four stream catchments

Inman River ; two disjunct populations, both small
and affected by stream drying

Tookayerta Creek; populations are reasonably
continuous but in a small catchment

Finniss River; a few highly restricted sites

Angas River; a single core pool, with recent loss of
fish from two tributary streams (Dawson and
Middle creeks).
Populations within individual streams are fragmented,
especially the Inman, Finniss and Angas catchments
and habitat conditions continue to deteriorate or have
a high potential for deterioration with habitat drying.3
Within the AMLR, only occurs in the Fleurieu Peninsula
and Lower Murray River Basins, within the South
Australian Gulf and Murray-Darling Drainage Divisions.2
Numerous records from the South East; most are post1970. Two earlier records were from swamps at
Kalangadoo (1912) and Kingston (1928). Records after
the 1970s (post drainage) are from across the region
and the species was widespread in the former
extensive wetland habitat. In the SAMDB, the species
was widespread in the fringing swamps and tributary
streams of the lower River Murray and Lake
Alexandrina (e.g. historically plentiful in the smaller
backwaters and swampy lowlands of the Finniss River),
and is also likely to have been found commonly in
areas associated with the River Murray through to VIC.
A new population in southern Fleurieu Peninsula
(Inman Catchment) was first documented in 2001;
long-term presence was subsequent confirmed by oral
history.3
Habitat
Habitat is varied but generally comprises smaller pools,
swamps and wetlands (plus some artificial refuges
including drains) with dense structure, either physical
such as rock and snags or submerged plants such as
Further information:
Biodiversity Conservation Unit, Adelaide Region
Phone: (61 8) 8336 0901 Fax: (61 8) 8336 0999
http://www.environment.sa.gov.au/
 Department for Environment and Heritage FIS 90346 May 2008
Prepared as part of the Regional Recovery Plan for Threatened Species and Ecological Communities of Adelaide and the Mount Lofty Ranges, South Australia 2009 - 2014
algae and Pond Weeds (Potamogeton), but most
often emergent or overhanging edge vegetation
such as grasses, Water Ribbons (Triglochin), Club Rush
(Schoenoplectus) and Cumbungi (Typha). Preferred
habitat can include large pools with edge cover
where large predatory fish are absent. Habitat often
comprises areas with cooler water temperatures; the
highest densities are in fenced or ungrazed areas.
Benefits from the seasonal inundation (winter/spring)
of edge and emergent vegetation as prime habitat
and cover for juveniles and shelter for adults during
floods.3
Biology and Ecology
The SAMDB lineage seems to be more sensitive to
habitat and flow changes. Individuals in spawning
condition have been noted in spring and
occasionally through summer in sites with permanent
cool flows. Feed on small invertebrates picked from
underwater surfaces. Individuals are short lived
(approximately four years) with only a small percent
of most populations older than one or two years (they
reach sexual maturity within a year). Movement is
fairly limited, especially in the streams of the MLR, with
dispersal occurring across inundated shallows rather
than against the flow.3
Aboriginal Significance
Post-1983 records indicate the AMLR distribution
occurs in Peramangk and Ngarrindjeri Nations.2
Threats
Reasons for population decline and continuing
threats include:

loss or degradation of habitat, notably swamps

altered flow regimes, delayed onset of seasonal
flows
due
to
water
abstraction
from
watercourses and the occurrence of unnatural
cycles of drying, can impede movement
between riparian areas and are likely to
become more pronounced with climate
change

loss or degradation of stream-side vegetation
and silting of watercourses, e.g. impact of
livestock

major barriers or disruptions to dispersal due to
instream structures, such as dams, reservoirs,
vertical weirs, road culverts

predation by and competition from introduced
fish species (trout, Eastern Gambusia and
possibly Redfin).3
Regional Distribution
Map based on filtered post-1983 records.2 Note, this map does not
necessarily represent the actual species’ distribution within the AMLR.
References
Note: In some cases original reference sources are not
included in this list, however they can be obtained from the
reference from which the information has been sourced (the
reference cited in superscript).
1 Department for Environment and Heritage (2003 ). Review
of the Status of Threatened Species in South Australia.
Proposed Schedules under the South Australian National Parks
and Wildlife Act 1972 Discussion Paper. National Parks and
Wildlife Council in partnership with the Department for
Environment and Heritage.
2 Department for Environment and Heritage (2007). Adelaide
and Mount Lofty Ranges Regional Recovery Pilot Project
Database. Unpublished data extracted and edited from
BDBSA, SA Herbarium (July 2007) and other sources.
3 Hammer, M., Wedderburn, S. and Van Weenen, J. (2007).
Action Plan for South Australian Freshwater Fishes: 2007-2012
Draft. Native Fish Australia (SA) Inc., Adelaide.
Additional current direct threats have been identified
and rated for this species. Refer to the main plan
accompanying these profiles.
Further information:
Biodiversity Conservation Unit, Adelaide Region
Phone: (61 8) 8336 0901 Fax: (61 8) 8336 0999
http://www.environment.sa.gov.au/
 Department for Environment and Heritage FIS 90346 May 2008
Prepared as part of the Regional Recovery Plan for Threatened Species and Ecological Communities of Adelaide and the Mount Lofty Ranges, South Australia 2009 - 2014