OCTOBER 2006 PRIMEFACT 145

Aquatic ecological community in the natural drainage system of the lowland catchment of the

Threatened Species Unit Fisheries Conservation and Aquaculture, Port Stephens

Introduction The aquatic ecosystem of the lower Lachlan River catchment has been greatly modified since European settlement, by river regulation, agricultural land uses and the introduction of non-native species. Species have declined in their numbers and distribution, some to the point where they are now listed as threatened. Photo: NSW Department of Natural Resources The aquatic ecological community in the natural drainage system of the lower Lachlan River • Lachlan River from Wyangala Dam to the catchment is listed as an endangered with the ; ecological community in NSW. This means • , below Carcoar that it is likely to become extinct in nature in NSW unless the circumstances and factors Dam, Mandagery Creek, Goobang Creek, and threatening its survival or evolutionary Crowie Creek; development cease to operate. The listing of • Lake Cowal, and its tributaries; the lowland Lachlan River aquatic ecological • Lake Brewster and Lake Cargelligo; community has several legal implications, including the establishment of heavy penalties • Effluent waters of Willandra Creek, Moolbang for harming species that form part of the Creek and Merrowie Creek; ecological community without appropriate • The Great Cumbung Swamp. authority. Impacts on the ecological community must be considered during development Barren Box Swamp and its catchment west of assessment processes, and the NSW the township of Mirrool, including the Mirrool Department of Primary Industries may prepare Creek, is excluded from the definition as the a recovery plan for the endangered ecological majority of water entering Barren Box Swamp is community. from the Murrumbidgee Irrigation Area. Artificial canals, water distribution and drainage works, farm dams and off-stream reservoirs are also Description excluded. Other watercourses above an altitude of 500 m above sea level that are not specified The aquatic ecological community of the above are also excluded. lowland Lachlan River catchment includes all native fish and aquatic invertebrates within all The community has a diverse assemblage of natural rivers, creeks, streams and associated native species including 19 species of fish, lagoons, billabongs, lakes, wetlands, paleo- 10 species of crustacean, 8 species of mollusc, channels, flood-runners, floodplains and 2 species of sponges, and many insects. effluent streams of the Lachlan River. The listing includes:

Habitat and ecology Reduced floodplain and wetland inundation, reducing the complexity and productivity of the • Most of the lower Lachlan River catchment is a ecosystem. lowland riverine environment characterised by meandering channels, wide floodplains, Thermal pollution associated with cold-water anabranches and effluent creeks. releases from Wyangala and Carcoar Dams, leading to spawning failures, inhibition of • Although small flows are contributed to the migration and loss of habitat for some fish Murrumbidgee River, the Lachlan River is species. considered to culminate in a broad expansive swamp known as the Great Cumbung Swamp. Water extraction for consumptive uses, decreasing flows to levels that may be • Many water bodies in the lowland Lachlan River detrimental to successful ecological function. catchment are characterised by variable and unpredictable patterns of high and low flows and Predation, competition, and diseases associated water levels. with introduced fish species including carp, goldfish, redfin perch, mosquito fish, rainbow • The variability in environmental conditions has trout, and brown trout. led to adaptations in the native aquatic flora and fauna. For example, many species rely on floods Degradation of the riparian zone resulting from to trigger spawning and create suitable breeding clearing native vegetation and stock trampling, habitats. leading to loss of shade and shelter, increased erosion and sedimentation, deterioration in • The lowland Lachlan River provides a wide habitat quality and availability, and reduction in range of habitats for fish and invertebrates, carbon inputs – the basis of food resources for including pools, runs or riffles, backwaters and in-stream invertebrates. billabongs, in-stream woody habitat, and aquatic plants. Declines in water quality associated with thermal pollution, pesticides, increased salinity, nutrient • The Lachlan River floodplain also provides a and turbidity levels, and increased incidences of mosaic of habitat types, including permanent blue-green algal blooms. and temporary wetlands, and terrestrial habitats. Loss of aquatic plants, contributing to the overall degradation and destabilisation of the aquatic Reasons why the aquatic ecological ecosystem, and associated reduction in community is endangered biodiversity. Modification of natural river flows resulting from Removal of in-stream large woody debris, river regulation (dams, weirs, etc), leading to reducing the amount and quality of aquatic reduced habitat quality, habitat fragmentation, habitat and sites available for reproduction of loss of spawning cues, and reduced fishes and invertebrates. opportunities for dispersal and migration of aquatic species. Agricultural practices such as irrigation, clearing, grazing and the use of fertilisers and pesticides, which have affected water quality and river flow.

PRIMEFACT 145, AQUATIC ECOLOGICAL COMMUNITY IN THE LOWLAND CATCHMENT OF THE LACHLAN RIVER 2 Over-fishing, which has probably contributed to Severe penalties can also apply for damaging past declines in populations of some species. the habitat of an endangered ecological Illegal fishing activities, targeted or incidental community without approval. Damage includes collection, and recreational catch of species actions such as dredging riverbeds and listed as endangered or vulnerable, still pose a constructing in-stream or floodplain barriers that threat. block the free passage of fish. Four of the native finfish species of the lower Clearing activities authorised by a property Lachlan ecological community are listed on the vegetation plan approved under the Native NSW threatened species schedules: olive Vegetation Act 2003 are permitted, provided the perchlet, silver perch, southern pygmy perch, native vegetation reform package had the benefit and purple spotted gudgeon. The river snail is of biodiversity certification at the time the endangered, and serious declines of at least two property vegetation plan was approved. other fish species native to the aquatic Clearing that constitutes a routine agricultural ecological community of the lowland Lachlan management activity and certain routine farming River catchment have been documented (eel tail practice activities (other than clearing) are catfish and river blackfish). permitted, provided the activities are to the minimum extent reasonably necessary and all Recovery actions that are underway other relevant statutory approvals or authorities have been obtained. Allocating and managing environmental water flows in regulated rivers through the water The impact of developments or activities that sharing plan processes, and reducing the impact require consent or approval (in accordance with of cold water originating from large dams. the Environmental Planning and Assessment Act 1979) must be assessed and considered by Riparian vegetation management and restoration consent or determining authorities. Where such projects being conducted by landholders, actions are likely to result in a significant impact community groups and Catchment Management on a threatened species or its habitat, a detailed Authorities. species impact statement must be prepared. Providing fish passage by removing barriers or Strategies to be adopted for promoting the installing fishways in consultation with affected recovery of the endangered ecological stakeholders. community to a position of viability in nature will Identifying and prioritising threats in the be set out in a Priorities Action Statement. endangered ecological community. A recovery plan may be prepared for the Conserving and, where possible, restoring endangered ecological community in accordance habitats through the protection of aquatic and with the provisions of the Fisheries Management riparian vegetation and encouraging the use of Act 1994 to promote the recovery of the effective erosion control measures. ecological community to a position of viability in nature. Developing and implementing control programs for introduced species. Arrangements are in place to allow continued recreational fishing for some of the popular Reinstating large woody habitat in waterways native species including: where appropriate. • Murray cod (Maccullochella peelii peelii) Sustainably managing fishing activities. • Golden perch (Macquaria ambigua)

Legal implications • Yabbies (Cherax destructor) • Freshwater shrimps (Paratya australiensis and The listing of the lowland Lachlan River aquatic Caridina mccullochi) ecological community has given all native fish and other aquatic animal life within its • Freshwater prawns (Macrobrachium boundaries the protected status of endangered australiense). species. Licensed inland commercial fishers with an Harming a member of an endangered ecological appropriate endorsement may also continue to community is an offence. Penalties can include take yabbies and carp. fines of up to $220,000 and up to 2 years All existing bag, size and possession limits, imprisonment. closures and other fishing restrictions continue to Harming, buying, selling or possessing a apply. threatened species is also an offence. Penalties For more information on fishing rules, check with can include fines of up to $220,000 and up to 2 your local fisheries office or on the Department years imprisonment. of Primary Industries website at www.dpi.nsw.gov.au

PRIMEFACT 145, AQUATIC ECOLOGICAL COMMUNITY IN THE LOWLAND CATCHMENT OF THE LACHLAN RIVER 3 Further reading Further information MDBC (2004). Fish theme pilot audit technical Phone Fisheries Information and Advisory report, Sustainable Rivers Audit, Murray Darling 1300 550 474 Basin Commission, . Norris R.H. et al. (2001), Snapshot of the Murray Contact the DPI Threatened Species Unit Darling Basin river condition, Murray Darling Port Stephens Fisheries Centre Basin Commission, Canberra. Locked Bag 1, Nelson Bay, NSW 2315 NSW Fisheries Scientific Committee, (2005), Fax (02) 4916 3880 Final Recommendation, Aquatic Ecological Email [email protected] Community in the Natural Drainage System of the Lowland Catchment of the Lachlan River. Published by NSW Department of Primary Industries © State of 2006 Roberts, J. and Sainty, G. (1996), Listening to the Lachlan, Sainty & Associates, Sydney. ISSN 1832-6668 Job number 6401

Updates of this Primefact are available at www.dpi.nsw.gov.au/primefacts

Disclaimer: The information contained in this publication is based on knowledge and understanding at the time of writing (October 2006). However, because of advances in knowledge, users are reminded of the need to ensure that information upon which they rely is up to date and to check currency of the information with the appropriate officer of New South Wales Department of Primary Industries or the user’s independent adviser.

Photo: NSW Department of Natural Resources

PRIMEFACT 145, AQUATIC ECOLOGICAL COMMUNITY IN THE LOWLAND CATCHMENT OF THE LACHLAN RIVER 4