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1
Rees, Gavin N., Gillian Beattie, Patricia M. Bowen, and Barry T. Hart. "Heterotrophic bacterial production in the lower Murray River, south-eastern Australia." Marine and Freshwater Research 56, no. 6 (2005): 835. http://dx.doi.org/10.1071/mf04232.
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Bacterial production is important in aquatic carbon cycles because it represents a key component whereby dissolved and particulate carbon can be recycled back into food webs. Despite its acknowledged importance, few studies have examined bacterial production in lowland rivers. Since studies have suggested bacterial production is closely related to some carbon pools, we anticipated this to be the case in the Murray River, but that the timing and type of carbon inputs in the Murray River may lead to bacterial dynamics that differ from studies from other sites. Bacterial abundance and production were measured at three contrasting sites of the lowland Murray River, south-eastern Australia, over an 18-month period. Bacterial abundance varied across the three sites on the Murray River and was correlated with chlorophyll a concentrations but not with temperature, nutrients, particulate organic carbon and dissolved organic carbon concentrations. Bacterial production also varied across the sites. Lowest production was at the site most immediately downstream of a large reservoir, with production generally ranging from 0.88 to 8.00 μg C L−1 h−1. Bacterial production in a reach within a large forest ranged from 4.00 to 17.38 μg C L−1 h−1. Production at the reach furthest downstream ranged from 1.04 to 23.50 μg C L−1 h−1. Bacterial production in the Murray River was generally greater than in the European River Spree, reaches of the Meuse and Rhine without immediate impacts from major urban centres and the Amazon River, but was similar to the concentration measured in the Mississippi and Hudson Rivers. Bacterial production was closely correlated with chlorophyll a concentration and total phosphorus, but not with temperature, dissolved organic carbon, particulate organic carbon or inorganic nitrogen. Despite the differences in production and respiration measured at different sites across the Murray River, bacterial growth efficiency was very similar at the three sites. Bacterial populations in the Murray River appear to be influenced by reach-specific conditions rather than broad-scale drivers such as temperature, carbon and nutrient concentrations.
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Waters, Jonathan M., Michael Shirley, and Gerard P. Closs. "Hydroelectric development and translocation of Galaxias brevipinnis: a cloud at the end of the tunnel?" Canadian Journal of Fisheries and Aquatic Sciences 59, no. 1 (January 1, 2002): 49–56. http://dx.doi.org/10.1139/f01-195.
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Two major drainages of southeastern Australia, the Snowy River and the Murray River, were artificially linked by a major hydroelectric project during the early 20th century. This development diverts Snowy River flow into tributaries of the Murray River via a series of extensive tunnels. In 1990, fish surveys of the upper Murray River system recorded Galaxias brevipinnis, an aggressive migratory species previously unrecorded from the drainage. We used genetic analysis to discriminate between alternative hypotheses for Murray River G. brevipinnis: (i) anthropogenic translocation via the Snowy River diversion or (ii) a previously undiscovered natural population. Landlocked G. brevipinnis from the Murray River (43 fish, eight control region haplotypes) and Snowy River (39 fish, 11 haplotypes) exhibit similar levels of mtDNA diversity, share six haplotypes, and are not significantly differentiated for microsatellite loci (p = 0.0884). Coastal samples exhibit higher haplotypic diversity (40 fish, 20 haplotypes) but share only three haplotypes with Murray River and are significantly differentiated from Murray River samples for microsatellite loci (p = 0.0008). Our data are consistent with the translocation hypothesis but are generally inconsistent with a natural origin for Murray River G. brevipinnis. The suggested human-mediated translocation represents a risk to native fauna.
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Maini, N., A. Buchan, and S. Joseph. "Derivation of a salinity target for the Lower Murray Darling Valley." Water Science and Technology 48, no. 7 (October 1, 2003): 105–12. http://dx.doi.org/10.2166/wst.2003.0430.
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The NSW Government commissioned catchment management boards (CMBs) to set the direction and process for catchment scale natural resource management. In the Lower Murray Darling, Rivers are highly regulated and water resources shared between three states. The Catchment Board only has jurisdiction over the northern bank of the Murray but salt and water enter the river from many locations upstream and along the area boundary. River salt and flow modelling has continually been improved to reflect and contribute to an increased understanding of salinity processes. The MDBC Salt Load study correlates 10 years of actual measured data with its modelled outputs, and estimates river salinities for 2020, 2050 and 2100. Routing models such as SALTFLO and MURKEY generate percentile salinity levels at different nodes in the River Murray downstream of the Lower Darling confluence. National, Murray-Darling Basin and NSW salinity management policy and legislative requirements were considered, MDBC model output was used to ensure the interim targets are achievable, auditable, and appropriate to the catchment. The method for an end-of-valley river based target for salinity is described. A target of less than 463 μS/cm for Lock 6, a point in the lower reaches of the Murray River is recommended for year 2010. Catchment management targets that express the main river salinity risk in five hydrologically distinct management zones are also recommended. Salinity management changes are needed in each zone to meet the end-of-valley target.
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Koehn, John D., and D. J. Harrington. "Collection and distribution of the early life stages of the Murray cod (Maccullochella peelii peelii) in a regulated river." Australian Journal of Zoology 53, no. 3 (2005): 137. http://dx.doi.org/10.1071/zo04086.
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The Murray cod (Maccullochella peelii peelii) is a large fish species keenly sought by anglers. However, this species has declined in distribution and abundance and is now listed nationally as vulnerable. This study was undertaken in the Ovens and Murray rivers, to collect larvae and age-0 Murray cod and determine the distribution of larval Murray cod around the mid-Murray River irrigation storage of Lake Mulwala. Murray cod larvae were collected from 17 of 18 sites: main channels and flowing anabranch channels of regulated and unregulated rivers, sites upstream and downstream of the lake, in the upper and lower reaches of the lake, and in the outflowing Yarrawonga irrigation channel. Larval Murray cod were collected only by methods that sampled drift in flowing waters. Age-0 Murray cod were collected by electrofishing in the main river, but not in off-channel waters, suggesting that cod are likely to settle into habitats in the main channel at a post-larval stage. The widespread occurrence of drifting larvae suggests that this species may be subject to previously unrecognised threats as they pass through hydro-electric power stations or become stranded in anabranch and irrigation channels. Results of this study are likely to be applicable to other species with drifting larval stages, and are relevant to other locations in the Murray–Darling Basin.
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Crook, David A., Damien J. O'Mahony, Bronwyn M. Gillanders, Andrew R. Munro, Andrew C. Sanger, Stephen Thurstan, and Lee J. Baumgartner. "Contribution of stocked fish to riverine populations of golden perch (Macquaria ambigua) in the Murray–Darling Basin, Australia." Marine and Freshwater Research 67, no. 10 (2016): 1401. http://dx.doi.org/10.1071/mf15037.
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Stocking of native fishes is conducted to augment riverine fisheries in many parts of the world, yet most stocking activities are conducted without empirical information on their effectiveness or impacts. In the Murray–Darling Basin (MDB), Australia, stocking has been underway for several decades to maintain recreational fisheries. We stocked chemically tagged golden perch (Macquaria ambigua) fingerlings in three rivers to determine the proportions of stocked fish within populations of the species. Stocked sites were monitored for up to 5 years in the Murrumbidgee River, Edward River and Billabong Creek and non-stocked sites were monitored in the Murray River. Catch per unit effort of stocked year classes increased substantially in Billabong Creek, with stocked fish contributing 100 (2005), 79 (2006) and 92% (2007). Chemically tagged fish comprised 18–38% of the respective age classes in the Murrumbidgee and Edward rivers and there was little evidence of natural recruitment in the non-stocked Murray River. Tagged fish generally attained the legal minimum size within 4 years and had dispersed up to 60km from the original release location. Our results demonstrate that artificial stocking has the potential to strongly influence the abundance and population structure of golden perch in rivers of the MDB.
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Bargrizan, Sima, Tapas K. Biswas, Klaus D. Joehnk, and Luke M. Mosley. "Sustained high CO." Marine and Freshwater Research 73, no. 4 (February 8, 2022): 540–51. http://dx.doi.org/10.1071/mf21154.
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Many of the world’s rivers have been found to be sources of CO2 to the atmosphere, however, there has been limited assessment in arid regions. This analysis of a long-term (1979–2013) dataset (n = 3496) along Australia’s largest river system (River Murray) showed that there were sustained high pCO2 (carbon dioxide partial pressure) levels, ranging from 1210 ± 107 to 3066 ± 579 µatm along the main river channel, and 5114 ± 1221 µatm on the major tributaries. As a consequence, the River Murray is a significant source of CO2 to the atmosphere, with an estimated average annual (±s.d.) flux of 218 ± 98 g C m−2 year−1 and total emissions of 355 000 ± 29 000 t CO2 year−1 over a total river area of 386 km2 from below Lake Hume to Tailem Bend, although there is some uncertainty with gas transfer coefficients. Supersaturation with CO2 relative to the atmosphere was maintained even under drought conditions with minimal external carbon inputs, suggesting internal carbon cycling and respiration is important in driving net CO2 production. Supersaturation of the river water relative to calcium carbonate minerals was also observed under low flow conditions. Hydro-climatic changes could be having significant impacts on the CO2 system in the River Murray and other arid river systems.
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Gippel, C., T. Jacobs, and T. McLeod. "Environmental flows and water quality objectives for the River Murray." Water Science and Technology 45, no. 11 (June 1, 2002): 251–60. http://dx.doi.org/10.2166/wst.2002.0402.
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Over the past decade, there intense consideration of managing flows in the River Murray to provide environmental benefits. In 1990 the Murray-Darling Basin Ministerial Council adopted a water quality policy: To maintain and, where necessary, improve existing water quality in the rivers of the Murray-Darling Basin for all beneficial uses - agricultural, environmental, urban, industrial and recreational, and in 1994 a flow policy: To maintain and where necessary improve existing flow regimes in the waterways of the Murray-Darling Basin to protect and enhance the riverine environment. The Audit of Water Use followed in 1995, culminating in the decision of the Ministerial Council to implement an interim cap on new diversions for consumptive use (the “Cap”) in a bid to halt declining river health. In March 1999 the Environmental Flows and Water Quality Objectives for the River Murray Project (the Project) was set up, primarily to establish water quality and environmental flow objectives for the River Murray system. A Flow Management Plan will be developed that aims to achieve a sustainable river environment and water quality, in accordance with community needs, and including an adaptive approach to management and operation of the River. It will lead to objectives for water quality and environmental flows that are feasible, appropriate, have the support of the scientific, management and stakeholder communities, and carry acceptable levels of risk. This paper describes four key aspects of the process being undertaken to determine the objectives, and design the flow options that will meet those objectives: establishment of an appropriate technical, advisory and administrative framework; establishing clear evidence for regulation impacts; undergoing assessment of environmental flow needs; and filling knowledge gaps. A review of the impacts of flow regulation on the health of the River Murray revealed evidence for decline, but the case for flow regulation as the main cause is circumstantial or uncertain. This is to be expected, because the decline of the River Murray results from many factors acting over a long period. Also, the health of the river varies along its length, from highly degraded to reasonably healthy, so it is clear that different approaches will be needed in the various river zones, with some problems requiring reach or even point scale solutions. Environmental flow needs have been determined through two major Expert Panel reports that identified the ecological priorities for the river. The next step is to translate these needs into feasible flow management actions that will provide the necessary hydrological conditions. Several investigations are underway to recommend options for flow management. Two important investigations are described in this paper: how to enhance flows to wetlands of national and international significance, and how to physically alter or change the operation of structures (including a dam, weir, lock, regulator, barrage or causeway), to provide significant environmental benefits. Early modelling suggests that the only option which has a positive environmental effect in all zones of the River is a reduction in overall water consumption.
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Tibby, John, and Michael A. Reid. "A model for inferring past conductivity in low salinity waters derived from Murray River (Australia) diatom plankton." Marine and Freshwater Research 55, no. 6 (2004): 597. http://dx.doi.org/10.1071/mf04032.
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Detecting human-induced salinisation in rivers and wetlands of the Murray-Darling Basin has proved problematic. A diatom-based model that permits the estimation of past electrical conductivity (EC) from sedimentary diatom sequences has been developed from Murray River planktonic diatoms. Canonical Correspondence Analysis indicates that EC explains the greatest amount of variance in Murray River planktonic diatoms and that its influence is partially independent of that associated with velocity, turbidity, pH and nutrients. A weighted-averaging based model for inferring past EC was therefore derived from the relationship between diatom composition and EC in Murray River plankton samples. The model works well when comparisons are made between measured and diatom-inferred EC determined by jackknifing based leave-one-out computer resampling (r2jack = 0.71, root-mean-square-error of prediction = 115 μS cm−1). Application of the model will enhance understanding of the nature of pre-European variability in electrical conductivity and permit detection of changes in conductivity through the period of European occupation at key sites. Such reconstructions will provide a firm empirical basis for assessing European impact on aquatic ecosystems and a means by which to assess restoration efforts.
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Fülöp, R. H., A. T. Codilean, K. M. Wilcken, T. J. Cohen, D. Fink, A. M. Smith, B. Yang, et al. "Million-year lag times in a post-orogenic sediment conveyor." Science Advances 6, no. 25 (June 2020): eaaz8845. http://dx.doi.org/10.1126/sciadv.aaz8845.
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Understanding how sediment transport and storage will delay, attenuate, and even erase the erosional signal of tectonic and climatic forcings has bearing on our ability to read and interpret the geologic record effectively. Here, we estimate sediment transit times in Australia’s largest river system, the Murray-Darling basin, by measuring downstream changes in cosmogenic 26Al/10Be/14C ratios in modern river sediment. Results show that the sediments have experienced multiple episodes of burial and reexposure, with cumulative lag times exceeding 1 Ma in the downstream reaches of the Murray and Darling rivers. Combined with low sediment supply rates and old sediment blanketing the landscape, we posit that sediment recycling in the Murray-Darling is an important and ongoing process that will substantially delay and alter signals of external environmental forcing transmitted from the sediment’s hinterland.
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Pittock, Jamie, and C. Max Finlayson. "Australia's Murray - Darling Basin: freshwater ecosystem conservation options in an era of climate change." Marine and Freshwater Research 62, no. 3 (2011): 232. http://dx.doi.org/10.1071/mf09319.
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River flows in the Murray–Darling Basin, as in many regions in the world, are vulnerable to climate change, anticipated to exacerbate current, substantial losses of freshwater biodiversity. Additional declines in water quantity and quality will have an adverse impact on existing freshwater ecosystems. We critique current river-management programs, including the proposed 2011 Basin Plan for Australia’s Murray–Darling Basin, focusing primarily on implementing environmental flows. River management programs generally ignore other important conservation and adaptation measures, such as strategically located freshwater-protected areas. Whereas most river-basin restoration techniques help build resilience of freshwater ecosystems to climate change impacts, different measures to enhance resilience and reoperate water infrastructure are also required, depending on the degree of disturbance of particular rivers on a spectrum from free-flowing to highly regulated. A crucial step is the conservation of free-flowing river ecosystems where maintenance of ecological processes enhances their capacity to resist climate change impacts, and where adaptation may be maximised. Systematic alteration of the operation of existing water infrastructure may also counter major climate impacts on regulated rivers.
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Ebner, B. "Murray cod an apex predator in the Murray River, Australia." Ecology of Freshwater Fish 15, no. 4 (December 2006): 510–20. http://dx.doi.org/10.1111/j.1600-0633.2006.00191.x.
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Kattel, G. R., X. Dong, and X. Yang. "A century scale human-induced hydrological and ecological changes of wetlands of two large river basins in Australia (Murray) and China (Yangtze): development of an adaptive water resource management framework." Hydrology and Earth System Sciences Discussions 12, no. 8 (August 24, 2015): 8247–87. http://dx.doi.org/10.5194/hessd-12-8247-2015.
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Abstract. Recently, the provision of food and water resources of two of the world's large river basins, the Murray and the Yangtze, has been significantly altered through widespread landscape modification. Long-term sedimentary archives, dating back to past centuries, from wetlands of these river basins reveal that rapid, basin-wide development has reduced resilience of biological communities, resulting in considerable decline in ecosystem services, including water quality. In particular, large-scale human disturbance to river systems, due to river regulation during the mid-20th century, has transformed the hydrology of rivers and wetlands, causing widespread disturbance to aquatic biological communities. Historical changes of cladoceran zooplankton (water fleas) were used to assess the hydrology and ecology of three Murray and Yangtze River wetlands over the past century. Subfossil assemblages of cladocerans retrieved from sediment cores (94, 45 and 65 cm) of three wetlands: Kings Billabong (Murray), Zhangdu and Liangzi Lakes (Yangtze) strongly responded to hydrological changes of the river after the mid-20th century. River regulation caused by construction of dams and weirs, and river channel modifications has led to hydrological alterations. The hydrological disturbances were either: (1) a prolonged inundation of wetlands, or (2) reduced river flow, which caused variability in wetland depth. These phenomena subsequently transformed the natural wetland habitats, leading to a switch in cladoceran assemblages preferring poor water quality and eutrophication. An adaptive water resource management framework for both of these river basins has been proposed to restore or optimize the conditions of wetland ecosystems impacted by 20th century human disturbance and climate change.
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Douglas, JW, GJ Gooley, BA Ingram, ND Murray, and LD Brown. "Natural hybridization between Murray cod, Maccullochella peelii peelii (Mitchell) and trout cod, Maccullochella macquariensis (Cuvier) (Percichthyidae) in the Murray River, Australia." Marine and Freshwater Research 46, no. 4 (1995): 729. http://dx.doi.org/10.1071/mf9950729.
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Hybridization is confirmed between two wild, naturally sympatric populations of Murray cod, Maccullochella peelii peelii, and trout cod, M. macquariensis, from the Murray River, Australia. Electrophoretic comparisons of proteins in muscle and liver tissues from trout cod, Murray cod, an artificially produced hybrid of Murray cod and trout cod, and putative wild hybrids from the Murray River indicated that the last group were first-generation interspecific hybrids. This is the first record of hybridization between naturally occumng populations of these two species. Naturally occurring wild populations of both trout cod and Murray cod are nonetheless genetically distinct and there is no evidence of introgression between the species. These findings have some implications for management policies and practices in relation to both species, and these are discussed.
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Kattel, Giri R., Xuhui Dong, and Xiangdong Yang. "A century-scale, human-induced ecohydrological evolution of wetlands of two large river basins in Australia (Murray) and China (Yangtze)." Hydrology and Earth System Sciences 20, no. 6 (June 3, 2016): 2151–68. http://dx.doi.org/10.5194/hess-20-2151-2016.
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Abstract. Recently, the provision of food and water resources of two of the world's largest river basins, the Murray and the Yangtze, has been significantly altered through widespread landscape modification. Long-term sedimentary archives, dating back for some centuries from wetlands of these river basins, reveal that rapid, basin-wide development has reduced the resilience of biological communities, resulting in considerable decline in ecosystem services, including water quality. Large-scale human disturbance to river systems, due to river regulation during the mid-20th century, has transformed the hydrology of rivers and wetlands, causing widespread modification of aquatic biological communities. Changes to cladoceran zooplankton (water fleas) were used to assess the historical hydrology and ecology of three Murray and Yangtze river wetlands over the past century. Subfossil assemblages of cladocerans retrieved from sediment cores (94, 45, and 65 cm) of three wetlands: Kings Billabong (Murray), Zhangdu, and Liangzi lakes (Yangtze), showed strong responses to hydrological changes in the river after the mid-20th century. In particular, river regulation caused by construction of dams and weirs together with river channel modifications, has led to significant hydrological alterations. These hydrological disturbances were either (1) a prolonged inundation of wetlands or (2) reduced river flow, both of which caused variability in wetland depth. Inevitably, these phenomena have subsequently transformed the natural wetland habitats, leading to a switch in cladoceran assemblages to species preferring poor water quality, and in some cases to eutrophication. The quantitative and qualitative decline of wetland water conditions is indicative of reduced ecosystem services, and requires effective restoration measures for both river basins which have been impacted by recent socioeconomic development and climate change.
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Auricht, Hannah C. C., Kenneth D. Clarke, Megan M. Lewis, and Luke M. Mosley. "Have droughts and increased water extraction from the Murray River (Australia) reduced coastal ocean productivity?" Marine and Freshwater Research 69, no. 3 (2018): 343. http://dx.doi.org/10.1071/mf17226.
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River discharges are decreasing in many regions of the world; however, the consequences of this on water quality and primary productivity of receiving coastal oceans are largely unclear. We analysed satellite remote-sensing data (MODIS) of the coastal ocean zone that receives outflows from the Murray River, from 2002 to 2016. This system has experienced historical flow reductions and a recent extreme hydrological ‘Millennium’ drought. Remotely sensed chlorophyll-a and particulate organic carbon in the coastal ocean were strongly correlated with river outflows (R2>0.6) in an 8-km radial buffer zone from the Murray Mouth, and the river influence extended up to ~60km from the Murray Mouth during high-flow periods. This distance was approximately three times greater than the freshwater plume extent during maximum flows in 2011, suggesting that new primary productivity was created. In contrast, there was no additional coastal ocean productivity above background levels from 2007 to 2010 when river outflows ceased. Hindcast calculations based on historical flows from 1962 to 2002 suggest that declining Murray River flows have greatly reduced primary productivity in adjacent coastal waters. This has potential consequences for higher trophic levels and should be considered in future management planning.
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Quiggin, John. "Murray River Salinity—An Illustrative Model." American Journal of Agricultural Economics 70, no. 3 (August 1988): 635–45. http://dx.doi.org/10.2307/1241502.
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Pryde, Kym. "Acting up over the river Murray." Australian Planner 41, no. 1 (January 2004): 30–31. http://dx.doi.org/10.1080/07293682.2004.9982328.
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Tadrowski, T., H. Tané, and P. Nanninga. "The River Murray on CD-ROM." Cartography 22, no. 2 (December 1993): 21–24. http://dx.doi.org/10.1080/00690805.1993.9713962.
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Stuart, Ivor G., and Matthew Jones. "Large, regulated forest floodplain is an ideal recruitment zone for non-native common carp (Cyprinus carpio L.)." Marine and Freshwater Research 57, no. 3 (2006): 333. http://dx.doi.org/10.1071/mf05035.
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Non-native common carp (Cyprinus carpio L.) are the most abundant large-bodied fish in the Murray–Darling Basin. The abundance of common carp larvae and young-of-the-year appears to increase after flooding, although the relative contribution of floodplain habitats compared to riverine areas remains unresolved. Larval nets were used monthly from September 2000 to January 2001 to identify common carp spawning and recruitment areas in the regulated Murray River and floodplain around the Barmah–Millewa forest. Five non-native and five native fish species comprising 136 111 individuals were collected, with common carp constituting 88% of the overall catch. Less than 1% of common carp, however, originated from the Murray River upstream of the Barmah–Millewa floodplain. Consequently, this floodplain appears to be a major source of common carp recruitment in the mid-Murray area. Conversely, eggs from large-bodied native fish were only present in the Murray River and not the Barmah floodplain. There are opportunities for common carp control in this area, to potentially reduce populations in a wider river reach. Implementation of common carp control measures in the Barmah–Millewa floodplain should be further investigated, particularly with regard to seasonal irrigation flows, obligatory migration routes and in the timing of future large-scale environmental water allocations.
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Couch, Alan J., Peter J. Unmack, Fiona J. Dyer, and Mark Lintermans. "Who’s your mama? Riverine hybridisation of threatened freshwater Trout Cod and Murray Cod." PeerJ 4 (October 27, 2016): e2593. http://dx.doi.org/10.7717/peerj.2593.
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Rates of hybridization and introgression are increasing dramatically worldwide because of translocations, restocking of organisms and habitat modifications; thus, determining whether hybridization is occuring after reintroducing extirpated congeneric species is commensurately important for conservation. Restocking programs are sometimes criticized because of the genetic consequences of hatchery-bred fish breeding with wild populations. These concerns are important to conservation restocking programs, including those from the Australian freshwater fish family, Percichthyidae. Two of the better known Australian Percichthyidae are the Murray Cod,Maccullochella peeliiand Trout Cod,Maccullochella macquariensiswhich were formerly widespread over the Murray Darling Basin. In much of the Murrumbidgee River, Trout Cod and Murray Cod were sympatric until the late 1970s when Trout Cod were extirpated. Here we use genetic single nucleotide polymorphism (SNP) data together with mitochondrial sequences to examine hybridization and introgression between Murray Cod and Trout Cod in the upper Murrumbidgee River and consider implications for restocking programs. We have confirmed restocked riverine Trout Cod reproducing, but only as inter-specific matings, in the wild. We detected hybrid Trout Cod–Murray Cod in the Upper Murrumbidgee, recording the first hybrid larvae in the wild. Although hybrid larvae, juveniles and adults have been recorded in hatcheries and impoundments, and hybrid adults have been recorded in rivers previously, this is the first time fertile F1 have been recorded in a wild riverine population. The F1 backcrosses with Murray cod have also been found to be fertile. All backcrosses noted were with pure Murray Cod. Such introgression has not been recorded previously in these two species, and the imbalance in hybridization direction may have important implications for restocking programs.
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Unmack, P. J., M. J. Young, B. Gruber, D. White, A. Kilian, X. Zhang, and A. Georges. "Phylogeography and species delimitation of Cherax destructor (Decapoda: Parastacidae) using genome-wide SNPs." Marine and Freshwater Research 70, no. 6 (2019): 857. http://dx.doi.org/10.1071/mf18347.
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Cherax is a genus of 58 species of decapod crustaceans that are widespread across Australia and New Guinea. We use single-nucleotide polymorphisms (SNPs) to examine phylogeographic patterns in the most widespread species of Cherax, namely, C. destructor, and test the distinctiveness of one undescribed species, two C. destructor subspecies, previously proposed evolutionarily significant units, and management units. Both the phylogenetic analyses and the analysis of fixed allelic differences between populations support the current species-level taxonomy of C. setosus, C. depressus, C. dispar and C. destructor, the distinctiveness of C. destructor albidus and C. d. destructor and the existence of one undescribed species. The two populations of C. d. albidus from the Glenelg and Wimmera rivers were significantly distinct, with eight diagnostic differences (<1% fixed differences, null expectation is four fixed differences), but this low level of divergence is interpreted as within the range that might be expected of management units, that is, among allopatric populations of a single species or subspecies. A southern clade of C. d. destructor comprising the Murray River and its tributaries upstream from its confluence with the Darling River is genetically distinct from a northern clade comprising populations from the Lake Eyre Basin, the northern half of the Murray–Darling Basin (Darling River catchment) and the Lower Murray River below the Darling confluence.
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Lieschke, J. A., J. P. Lyon, P. D. Moloney, and S. J. Nicol. "Spatial partitioning in the use of structural woody habitat supports the cohabitation of two cod species in a large lowland river." Marine and Freshwater Research 67, no. 12 (2016): 1835. http://dx.doi.org/10.1071/mf15067.
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Many freshwater fish worldwide have been shown to use Structural Woody Habitat (SWH) for a variety of reasons. The mid reaches of the Murray River, a large lowland river in south-eastern Australia, was surveyed by boat electrofishing, to investigate the use of SWH type (hollows, rootmass and solids), SWH distance to bank (near bank, intermediate to bank and mid-channel) and the interaction between SWH type and distance to bank. The study found that Murray cod catch per unit effort (CPUE) increased in near-bank areas when hollows were a component of the SWH. The CPUE of trout cod was higher when hollows were present. However, the interactions between distance to bank and hollow SWH were complex and dependent on presence or absence of rootmass. The species-specific interactions between SWH microhabitat and distance to bank found within this study has important relevance for stream managers. The common practice of realigning SWH favours Murray cod over trout cod, which could have negative consequences for the endangered trout cod. More broadly, managers may need to consider a balance of SWH type and where it is placed in the river for the species they are targeting when rehabilitating rivers via the introduction of SWH.
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Leigh, Sandra J., and Brenton P. Zampatti. "Movement and mortality of Murray cod, Maccullochella peelii, during overbank flows in the lower River Murray, Australia." Australian Journal of Zoology 61, no. 2 (2013): 160. http://dx.doi.org/10.1071/zo12124.
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Conservation of Murray cod (Maccullochella peelii), a large endangered fish species of Australia’s Murray–Darling Basin, relies on a detailed understanding of life history, including movement patterns and habitat use. We used radio-tracking to investigate the movement of 36 Murray cod in main channel and anabranch habitats of the lower River Murray during a flood and associated hypoxic blackwater event. During a flood peak of ~93 000 ML day–1, dissolved oxygen decreased to 1.2 mg L–1. Four movement types were observed: (1) localised small-scale movement, (2) broad-scale movement within anabranch habitats, (3) movement between anabranch and main channel habitats, and (4) large-scale riverine movement. Murray cod exhibited high fidelity to anabranch habitats but also moved extensively between anabranches and the main channel. Fish were consistently located in the main channel or permanent anabranches, suggesting that use of ephemeral floodplain habitats is limited, and highlighting the importance of connectivity between off-channel and main channel habitats. Mortality of radio-tagged fish was considerable (25%) in association with low dissolved oxygen concentrations, indicating that hypoxic blackwater may have had a substantial impact on Murray cod populations in the lower River Murray.
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MacDonald, Darla Hatton, Mark D. Morrison, John M. Rose, and Kevin J. Boyle. "Valuing a multistate river: the case of the River Murray*." Australian Journal of Agricultural and Resource Economics 55, no. 3 (June 15, 2011): 374–92. http://dx.doi.org/10.1111/j.1467-8489.2011.00551.x.
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Alaghmand, S., S. Beecham, and A. Hassanli. "Fully integrated physically-based numerical modelling of impacts of groundwater extraction on surface and irrigation-induced groundwater interactions: case study Lower River Murray, Australia." Natural Hazards and Earth System Sciences Discussions 1, no. 4 (July 26, 2013): 3577–624. http://dx.doi.org/10.5194/nhessd-1-3577-2013.
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Abstract. Combination of reduction in the frequency, duration and magnitude of natural floods, rising saline water-table in floodplains and excessive evapotranspiration have led to an irrigation-induced groundwater mound forced the naturally saline groundwater onto the floodplain in the Lower River Murray. It is during the attenuation phase of floods that these large salt accumulations are likely to be mobilised and will discharge into the river. The Independent Audit Group for Salinity highlighted this as the most significant risk in the Murray–Darling Basin. South Australian government and catchment management authorities have developed salt interception schemes (SIS). This is to pump the highly saline groundwater from the floodplain aquifer to evaporation basins in order to reduce the hydraulic gradient that drives the regional saline groundwater towards the River Murray. This paper investigates the interactions between a river (River Murray in South Australia) and a saline semi-arid floodplain (Clarks Floodplain) significantly influenced by groundwater lowering (Bookpurnong SIS). Results confirm that groundwater extraction maintain a lower water-table and more fresh river water flux to the saline floodplain aquifer. In term of salinity, this may lead to less amount of solute stored in the floodplain aquifer. This occurs through two mechanisms; extracting some of the solute mass from the system and changing the floodplain groundwater regime from a losing to gaining one. Finally, it is shown that groundwater extraction is able to remove some amount of solute stored in the unsaturated zone and mitigate the floodplain salinity risk.
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Waterhouse, Richard, and Paul Sinclair. "The Murray: A River and its People." Labour History, no. 87 (2004): 270. http://dx.doi.org/10.2307/27516017.
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Davie, Alec W., and Joe B. Pera. "The Fish Health Risk Indicator: linking water quality and river flow data with fish health to improve our predictive capacity around fish death events." Marine and Freshwater Research 73, no. 2 (2022): 193. http://dx.doi.org/10.1071/mf20360.
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Severe drought conditions contributed to three mass fish mortality events in the Darling River near Menindee, part of the Murray–Darling Basin, Australia, during the summer of 2018–19. An independent assessment recommended the need for improved modelling approaches to identify when sections of rivers may be more susceptible to fish kill events. We present a geographic information system (GIS)-based tool that combines meteorological forecasts with river flow and algal biomass datasets to identify river reaches where additional stresses on fish health may produce an increased risk of mass fish deaths. At present the tool is still in development and will require the addition of extra datasets and testing using historical datasets to further validate its accuracy. Despite the tool being in its development stage, the decision support tool has been widely accepted and provides natural resource managers with a rapid way to understand and communicate risks to fish health, supporting improved water management options across the Murray–Darling Basin that may ultimately help reduce the frequency and severity of large-scale fish mortality events.
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Lyon, Jarod, Ivor Stuart, David Ramsey, and Justin O'Mahony. "The effect of water level on lateral movements of fish between river and off-channel habitats and implications for management." Marine and Freshwater Research 61, no. 3 (2010): 271. http://dx.doi.org/10.1071/mf08246.
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Off-channel habitats, such as wetlands and backwaters, are important for the productivity of river systems and for many species of native fish. This study aimed to investigate the fish community, timing and cues that stimulated movement to and from off-channel habitats in the highly regulated Lake Hume to Lake Mulwala reach of the Murray River, south-eastern Australia. In 2004–05, 193 712 fish were collected moving bi-directionally between a 50-km section of the Murray River and several off-channel habitats. Lateral fish movements approximated water level fluctuations. Generally as water levels rose, fish left the main river channel and moved into newly flooded off-channel habitats; there was bi-directional movement as water levels peaked; on falling levels fish moved back to the permanent riverine habitats. Fish previously classified as ‘wetland specialists’, such as carp gudgeons (Hypseleotris spp.), have a more flexible movement and life-history strategy including riverine habitation. The high degree of lateral movement indicates the importance of habitat connectivity for the small-bodied fish community. Wetlands adjacent to the Murray River are becoming increasingly regulated by small weirs and ensuring lateral fish movement will be important in maintaining riverine-wetland biodiversity.
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Garrick, Dustin, Lucia De Stefano, Fai Fung, Jamie Pittock, Edella Schlager, Mark New, and Daniel Connell. "Managing hydroclimatic risks in federal rivers: a diagnostic assessment." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 371, no. 2002 (November 13, 2013): 20120415. http://dx.doi.org/10.1098/rsta.2012.0415.
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Hydroclimatic risks and adaptive capacity are not distributed evenly in large river basins of federal countries, where authority is divided across national and territorial governments. Transboundary river basins are a major test of federal systems of governance because key management roles exist at all levels. This paper examines the evolution and design of interstate water allocation institutions in semi-arid federal rivers prone to drought extremes, climatic variability and intensified competition for scarce water. We conceptualize, categorize and compare federal rivers as social–ecological systems to analyse the relationship between governance arrangements and hydroclimatic risks. A diagnostic approach is used to map over 300 federal rivers and classify the hydroclimatic risks of three semi-arid federal rivers with a long history of interstate allocation tensions: the Colorado River (USA/Mexico), Ebro River (Spain) and Murray–Darling River (Australia). Case studies review the evolution and design of water allocation institutions. Three institutional design trends have emerged: adoption of proportional interstate allocation rules; emergence of multi-layered river basin governance arrangements for planning, conflict resolution and joint monitoring; and new flexibility to adjust historic allocation patterns. Proportional allocation rules apportion water between states based on a share of available water, not a fixed volume or priority. Interstate allocation reform efforts in the Colorado and Murray–Darling rivers indicate that proportional allocation rules are prevalent for upstream states, while downstream states seek reliable deliveries of fixed volumes to increase water security. River basin governance arrangements establish new venues for multilayered planning, monitoring and conflict resolution to balance self governance by users and states with basin-wide coordination. Flexibility to adjust historic allocation agreements, without risk of defection or costly court action, also provides adaptive capacity to manage climatic variability and shifting values. Future research should develop evidence about pathways to adaptive capacity in different classes of federal rivers, while acknowledging limits to transferability and the need for context-sensitive design.
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Alaghmand, S., S. Beecham, and A. Hassanli. "Impacts of groundwater extraction on salinization risk in a semi-arid floodplain." Natural Hazards and Earth System Sciences 13, no. 12 (December 23, 2013): 3405–18. http://dx.doi.org/10.5194/nhess-13-3405-2013.
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Abstract. In the lower River Murray in Australia, a combination of a reduction in the frequency, duration and magnitude of natural floods, rising saline water tables in floodplains, and excessive evapotranspiration have led to an irrigation-induced groundwater mound forcing the naturally saline groundwater onto the floodplain. It is during the attenuation phase of floods that these large salt accumulations are likely to be mobilised and discharged into the river. This has been highlighted as the most significant risk in the Murray–Darling Basin and the South Australian Government and catchment management authorities have subsequently developed salt interception schemes (SIS). The aim of these schemes is to reduce the hydraulic gradient that drives the regional saline groundwater towards the River Murray. This paper investigates the interactions between a river (River Murray in South Australia) and a saline semi-arid floodplain (Clark's floodplain) that is significantly influenced by groundwater lowering due to a particular SIS. The results confirm that groundwater extraction maintains a lower water table and a higher amount of fresh river water flux to the saline floodplain aquifer. In terms of salinity, this may lead to less solute stored in the floodplain aquifer. This occurs through three mechanisms, namely extraction of the solute mass from the system, reducing the saline groundwater flux from the highland to the floodplain and changing the floodplain groundwater regime from a losing to a gaining one. It is shown that groundwater extraction is able to remove some of the solute stored in the unsaturated zone and this can mitigate the floodplain salinity risk. A conceptual model of the impact of groundwater extraction on floodplain salinization has been developed.
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Bormans, Myriam, Holger Maier, Michael Burch, and Peter Baker. "Temperature stratification in the lower River Murray, Australia: implication for cyanobacterial bloom development." Marine and Freshwater Research 48, no. 7 (1997): 647. http://dx.doi.org/10.1071/mf97058.
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The relationship between temperature stratification of the water column, river discharge and meteorological forcing was examined for the lower River Murray by using a combination of field measurements and a simple mixing criterion. Wind was found to be the dominant variable affecting the degree of temperature stratification under low flow conditions typical of summer. The results of a three-month intensive study were used in conjunction with six years of historical data to determine the stratification potential of the lower River Murray and its implication for water quality and cyanobacterial bloom development. The physical characteristics and therefore stratification behaviour of the water column in the river section studied are not conducive to sustained blooms at any time of the year because of a combination of strong winds and sufficiently high river discharges.
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Stuart, Ivor, Clayton Sharpe, Kathryn Stanislawski, Anna Parker, and Martin Mallen-Cooper. "From an irrigation system to an ecological asset: adding environmental flows establishes recovery of a threatened fish species." Marine and Freshwater Research 70, no. 9 (2019): 1295. http://dx.doi.org/10.1071/mf19197.
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Worldwide, riverine fish are the target of environmental water because populations have declined in lotic river habitats following river regulation. Murray cod is an endangered Australian riverine fish with remaining populations associated with lotic river reaches with instream habitat, including some creeks operated as part of irrigation systems. Our objectives were to develop a life history model, apply the building block method of environmental flows to enhance the abundance of juvenile Murray cod and promote population recovery. From 2008 to 2018 we evaluated changes to Murray cod juvenile abundance before and after implementation of a perennial environmental flow regime that began in 2013. During the first year of the environmental flow, larvae were collected as evidence of spawning. Murray cod abundance can be enhanced with environmental flows that target: (1) an annual spring spawning or recruitment flow with no rapid water level drops; (2) maximising hydrodynamic complexity (i.e. flowing habitats that are longitudinally continuous and hydrodynamically complex); and (3) an annual base winter connection flow. Recognition that incorporating hydraulics (water level and velocity) at fine and coarse time scales, over spatial scales that reflect life histories, provides broader opportunities to expand the scope of environmental flows to help restore imperilled fish species in regulated ecosystems.
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Allen, Harry. "Native companions: Blandowski, Krefft and the Aborigines on the Murray River expedition." Proceedings of the Royal Society of Victoria 121, no. 1 (2009): 129. http://dx.doi.org/10.1071/rs09129.
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This paper explores relations between Blandowski, Krefft and the Aborigines during the 1856-57 Murray River expedition. As with many scientific enterprises in Australia, Aboriginal knowledge made a substantial contribution to the success of the expedition. While Blandowski generously acknowledged this, Krefft, who was responsible for the day to day running of the camp, maintained his distance from the Aborigines. The expedition context provides an insight into tensions between Blandowski and Krefft, and also into the complexities of the colonial project on the Murray River, which involved Aborigines, pastoralists, missionaries and scientists.
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Sheldon, Fran, and Keith F. Walker. "Spatial distribution of littoral invertebrates in the lower Murray - Darling River system, Australia." Marine and Freshwater Research 49, no. 2 (1998): 171. http://dx.doi.org/10.1071/mf96062.
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The abundance and richness of macroinvertebrates in the lower Murray and Darling rivers were examined at a macroscale (rivers), mesoscale (billabongs, backwaters, channel) and microscale (vegetation, snags, substrata). In the Darling, insects dominated (85% of taxa, 81% of individuals); the richest taxa were Diptera (26 taxa) and Coleoptera (15 taxa) and the most abundant were Hemiptera (47%) and Diptera (35%). In the Murray, insects again dominated (84% of taxa, 52% of individuals), particularly Diptera (22 taxa), Coleoptera (12 taxa) and Hemiptera (9 taxa), but there were more crustaceans (9% of taxa, 47% of individuals, particularly the atyid shrimp Paratya australiensis). Both assemblages were uneven: in the Darling, >50% of biomass was Micronecta spp. (Corixidae), Dicrotendipes sp. (Chironomidae) and Macrobrachium australiense (Palaemonidae); in the Murray, 70% of biomass was P. australiensis and Caridina mccullochi (Atyidae) and the insects Micronecta spp. (Corixidae) and Chironomus sp. (Chironomidae). Abundances generally were greatest in the Murray. Hydrologic and geomorphic factors influenced assemblages at the macroscale, whereas microhabitat diversity dominated at the mesoscale.
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Parsons, Melissa, Martin C. Thoms, and Joseph E. Flotemersch. "Eight river principles for navigating the science–policy interface." Marine and Freshwater Research 68, no. 3 (2017): 401. http://dx.doi.org/10.1071/mf15336.
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Scientists and policymakers often work together to develop policy about the sustainable use of river ecosystems. River science plays an important role in developing river policy but how can key aspects of river science be conveyed as a heuristic to navigate the interface between river science and river policy? This paper introduces eight principles that encapsulate the key properties of rivers to consider during the development of river policy: (1) rivers are social–ecological systems; (2) river ecosystems provide valuable ecosystem services; (3) tools should support policy development; (4) knowledge of river ecosystems will always be incomplete; (5) social–ecological systems require interdisciplinary perspectives; (6) science is one of many inputs to be considered; (7) heterogeneity and variability are characteristic of river ecosystems; and (8) scale awareness is essential in river ecosystems. Whereas policy challenges are associated with each principle, consideration of principles in the context of the issue at hand may increase the robustness of river policy and enhance the sustainability of river ecosystems. The eight principles are evaluated in relation to the Water Act 2007 and the draft Murray–Darling Basin Plan to demonstrate how the principles can enhance policy development in the area of water allocation.
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Doody, Tanya M., Simon N. Benger, Jodie L. Pritchard, and Ian C. Overton. "Ecological response of Eucalyptus camaldulensis (river red gum) to extended drought and flooding along the River Murray, South Australia (1997–2011) and implications for environmental flow management." Marine and Freshwater Research 65, no. 12 (2014): 1082. http://dx.doi.org/10.1071/mf13247.
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Riparian forest and woodlands of the lower River Murray floodplain are exhibiting deteriorating health as a result of anthropogenic alterations to flow regimes and south-eastern Australia’s long-term ‘Millennium Drought’ from 1997 to 2009. Extensive flooding in 2010/2011 brought the drought to an end, providing an opportunity to monitor ecological floodplain recovery. The relationship between flooding and lateral recharge and condition of the dominant riparian tree species, Eucalyptus camaldulensis, was determined between 2007 and 2011 using the Landsat (LTM5) Normalised Difference Vegetation Index (NDVI). Linking the river hydrograph with the River Murray Floodplain Inundation Model (RiM-FIM) allowed exploration of the relationship between inundation duration and E. camaldulensis water requirements. Results indicate lateral bank recharge is an important mechanism in the maintenance of vegetation condition along the River Murray channel. Higher in-channel irrigation water delivery during summer months was identified as critical to survival of trees adjacent to the channel during the drought. The research suggests that weir pool manipulation to create in-channel flood pulses will aid E. camaldulensis maintenance. Furthermore, release of environmental flows once every 3 to 5 years to create bank-full flow or preferably overbank flows, will increase hydrological connectivity between river banks, wetlands and riparian zones, providing positive ecological benefits to E. camaldulensis and other floodplain and aquatic ecological assets.
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Gehrke, Peter C., and John H. Harris. "Large-scale patterns in species richness and composition of temperate riverine fish communities, south-eastern Australia." Marine and Freshwater Research 51, no. 2 (2000): 165. http://dx.doi.org/10.1071/mf99061.
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Riverine fish in New South Wales were studied to examine longitudinal trends in species richness and to identify fish communities on a large spatial scale. Five replicate rivers of four types (montane, slopes, regulated lowland and unregulated lowland) were selected from North Coast, South Coast, Murray and Darling regions. Fishwere sampled during summer and winter in two consecutive years with standardized gear that maximized the range of species caught. The composition of fish communities varied among regions and river types, with little temporal variation. Distinct regional communities converged in montane reaches and diverged downstream. The fish fauna can be classified into North Coast, South Coast, Murray and Darling communities, with a distinct montane community at high elevations irrespective of the drainage division. Species richness increased downstream in both North Coast and South Coast regions by both replacement and the addition of new species. In contrast, species richness in the Darling and Murray regions reached a maximum in the slopes reaches and then declined, reflecting a loss of species in lowland reaches. The small number of species is typical of the freshwater fish faunas of similar climatic regions world-wide. Fish communities identified in this study form logical entities for fisheries management consistent with the ecosystem-focused, catchment-based approach to river management and water reform being adopted in Australia.
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Cook, Robert A., Ben Gawne, Rochelle Petrie, Darren S. Baldwin, Gavin N. Rees, Daryl L. Nielsen, and Nathan S. P. Ning. "River metabolism and carbon dynamics in response to flooding in a lowland river." Marine and Freshwater Research 66, no. 10 (2015): 919. http://dx.doi.org/10.1071/mf14199.
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Lowland riverine–floodplain systems often have significant but irregular inputs of allochthonous carbon. However, the importance of this carbon to riverine systems remains poorly understood. We assessed open water dissolved organic carbon (DOC) concentrations, metabolism and biofilm stable isotope (δ13C) signatures, upstream and downstream of an extensive floodplain forest on the Murray River, Australia, before and after a flood event. Prior to flooding, all sites had similar concentrations of DOC, rates of metabolism and biofilm δ13C signatures. During the flood DOC concentration increased up to three-fold downstream of the forest, gross primary production (GPP) increased at all sites, but community respiration (CR) increased only at the downstream sites, resulting in decreased in NPP downstream and a slight increase upstream. Biofilm δ13C signatures became depleted by between 4 and 7‰ downstream of the forest during the flood, reflecting a rapid incorporation of allochthonous carbon into the biofilm. These results indicate that flooding led to a substantial increase to the energy budget of the Murray River through the provisioning of large quantities of allochthonous carbon and that terrestrial carbon was processed within the river biofilms. Allochthonous carbon assimilation within biofilms during flooding provides a potential pathway for allochthonous carbon to be incorporated into the metazoan foodweb.
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Pigram, John J. "Towards Upstream-Downstream HydrosolidarityAustralia's Murray-Darling River Basin." Water International 25, no. 2 (June 2000): 222–26. http://dx.doi.org/10.1080/02508060008686822.
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Quiggin, John. "Environmental economics and the Murray–Darling river system." Australian Journal of Agricultural and Resource Economics 45, no. 1 (March 2001): 67–94. http://dx.doi.org/10.1111/1467-8489.00134.
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Thomas, G. A., and A. J. Jakeman. "Management of salinity in the river Murray basin." Land Use Policy 2, no. 2 (April 1985): 87–102. http://dx.doi.org/10.1016/0264-8377(85)90002-x.
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Davies, P. E., J. H. Harris, T. J. Hillman, and K. F. Walker. "The Sustainable Rivers Audit: assessing river ecosystem health in the Murray - Darling Basin, Australia." Marine and Freshwater Research 61, no. 7 (2010): 764. http://dx.doi.org/10.1071/mf09043.
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The Sustainable Rivers Audit (SRA) is a systematic assessment of the health of river ecosystems in the Murray–Darling Basin (MDB), Australia. It has similarities to the United States’ Environmental Monitoring and Assessment Program, the European Water Framework Directive and the South African River Health Program, but is designed expressly to represent functional and structural links between ecosystem components, biophysical condition and human interventions in the MDB. Environmental metrics derived from field samples and/or modelling are combined as indicators of condition in five themes (Hydrology, Fish, Macroinvertebrates, Vegetation and Physical Form). Condition indicator ratings are combined using expert-system rules to indicate ecosystem health, underpinned by conceptual models. Reference condition, an estimate of condition had there been no significant human intervention in the landscape, provides a benchmark for comparisons. To illustrate, a synopsis is included of health assessments in 2004–2007. This first audit completed assessments of condition and ecosystem health at the valley scale and in altitudinal zones, and future reports will include trend assessments. SRA river-health assessments are expected to play a key role in future water and catchment management through integration in a Basin Plan being developed by the Murray–Darling Basin Authority for implementation after 2011. For example, there could be links to facilitate monitoring against environmental targets.
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Shuttleworth, B., A. Woidt, T. Paparella, S. Herbig, and D. Walker. "The dynamic behaviour of a river-dominated tidal inlet, River Murray, Australia." Estuarine, Coastal and Shelf Science 64, no. 4 (September 2005): 645–57. http://dx.doi.org/10.1016/j.ecss.2005.04.007.
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Gehrke, P. C., P. Brown, C. B. Schiller, D. B. Moffatt, and A. M. Bruce. "River regulation and fish communities in the Murray-Darling river system, Australia." Regulated Rivers: Research & Management 11, no. 3-4 (November 1995): 363–75. http://dx.doi.org/10.1002/rrr.3450110310.
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Whiterod, Nick R., and Keith F. Walker. "Will rising salinity in the Murray - Darling Basin affect common carp (Cyprinus carpio L.)?" Marine and Freshwater Research 57, no. 8 (2006): 817. http://dx.doi.org/10.1071/mf06021.
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Salinisation in the Murray–Darling Basin, Australia, may affect aquatic flora and fauna, including the common carp, an alien species that has become the most common fish in the river system. This study describes the responses of juvenile carp (31–108 mm total length) to salinity levels that prevail in some wetlands of the lower reaches of the River Murray. Carp are moderately tolerant of salinity (direct transfer LC50: 11 715 mg L–1), particularly after slow acclimation (LC50: 13 070 mg L–1), but sub-lethal effects are evident at lower salinities. These include effects on osmoregulation (>7500 mg L–1), behaviour (7500–12 500 mg L–1) and sperm motility in mature fish (150–300 mm) (8330 mg L–1). Salinities in some Murray–Darling Basin wetlands already approach half seawater (17 500 mg L–1) and carp populations in these important nursery areas could be impacted through sub-lethal effects on adults and lethal effects on juveniles, eggs and sperm.
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Watkins, Susanne C., G. P. Quinn, and Ben Gawne. "Changes in organic-matter dynamics and physicochemistry, associated with riparian vegetation loss and river regulation in floodplain wetlands of the Murray River, Australia." Marine and Freshwater Research 61, no. 10 (2010): 1207. http://dx.doi.org/10.1071/mf09312.
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Extensive clearing of floodplain forests potentially reduces organic matter available to floodplain wetlands. Furthermore, on rivers regulated to provide irrigation water in summer, floodplain wetlands that were previously inundated in spring, now flood in summer/autumn. In the Murray–Darling Basin, Australia, this has changed the timing of organic matter entering the aquatic phase, since leaf fall peaks in summer. Field surveys and mesocosm experiments on floodplain wetlands on the River Murray revealed faster processing rates of leaves in summer/autumn than spring, and no difference between cleared and forested wetlands. Temperature and leaf carbon : nitrogen ratio could not explain these differences, and instead, changes to leaf chemistry associated with ‘terrestrial ageing’ between peak leaf fall in summer and inundation in spring is more likely. The results indicated that the reduction of input of organic matter through riparian tree clearing and changing the timing of inundation interact to alter organic-matter standing stocks and rates of decomposition in floodplain wetlands. Restoring both natural timing of high flows and riparian vegetation might be required for recovery of these wetlands.
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Draper, Clara, and Graham Mills. "The Atmospheric Water Balance over the Semiarid Murray–Darling River Basin." Journal of Hydrometeorology 9, no. 3 (June 1, 2008): 521–34. http://dx.doi.org/10.1175/2007jhm889.1.
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Abstract The atmospheric water balance over the semiarid Murray–Darling River basin in southeast Australia is analyzed based on a consecutive series of 3- to 24-h NWP forecasts from the Australian Bureau of Meteorology’s Limited Area Prediction System (LAPS). Investigation of the LAPS atmospheric water balance, including comparison of the forecast precipitation to analyzed rain gauge observations, indicates that the LAPS forecasts capture the general qualitative features of the water balance. The key features of the atmospheric water balance over the Murray–Darling Basin are small atmospheric moisture flux divergence (at daily to annual time scales) and extended periods during which the atmospheric water balance terms are largely inactive, with the exception of evaporation, which is consistent and very large in summer. These features present unique challenges for NWP modeling. For example, the small moisture fluxes in the basin can easily be obscured by the systematic errors inherent in all NWP models. For the LAPS model forecasts, there is an unrealistically large evaporation excess over precipitation (associated with a positive bias in evaporation) and unexpected behavior in the moisture flux divergence. Two global reanalysis products (the NCEP Reanalysis I and the 40-yr ECMWF Re-Analysis) also both describe (physically unrealistic) long-term negative surface water budgets over the Murray–Darling Basin, suggesting that the surface water budget cannot be sensibly diagnosed based on output from current NWP models. Despite this shortcoming, numerical models are in general the most appropriate tool for examining the atmospheric water balance over the Murray–Darling Basin, as the atmospheric sounding network in Australia has extremely low coverage.
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Hatch, Michael, Tim Munday, and Graham Heinson. "A comparative study of in-river geophysical techniques to define variations in riverbed salt load and aid managing river salinization." GEOPHYSICS 75, no. 4 (July 2010): WA135—WA147. http://dx.doi.org/10.1190/1.3475706.
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Increased interest in the character of sediments at the base of waterways, for the purpose of managing river salinization, has led to the application of several geophysical techniques for collecting information from this zone. These instream methods are based on established ground and airborne electrical and electromagnetic technologies, including towed transient electromagnetic systems, towed direct current resistivity array systems, and frequency-domain helicopter electromagnetic systems. Although these systems are individually successful, a systematic examination of their relative effectiveness for identifying variations in substrate conductivity for a common stretch of a river remains lacking. We have compared results obtained from data collected using three instream geophysical techniques for a common stretch of the Murray River in southeastern Australia. The Murray River is an important water resource for drinking and agricultural purposes. Data from these surveys were acquired tolocate areas of significant saltwater accession to the Murray from a saline regional groundwater system that discharges into it. The three methods indirectly inform on those reaches that most likely contribute to higher salt loads in the river, and they do this through the identification of a conductive substrate (a gaining reach). For a [Formula: see text] stretch of the river, the methods identified similar variations in the conductivity structure of sediment substrate, although differences were observed in the modeled response relating to intrinsic differences between each system, including the sampling interval and resolution. The helicopter electromagnetic (EM) system is capable of acquiring hundreds of kil-ometers of data in a day, under any river flow condition, from near the river surface to depths in excess of [Formula: see text]. The other two techniques require safe river flow conditions for acquisition, with as much as 50 river km of data per day possible. The ground-based methods had enhanced lateral and vertical resolving capabilities relative to the helicopter EM system, but their depth of investigation was less (usually only [Formula: see text]).
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Yang, Ang, Geoff Podger, Shane Seaton, and Robert Power. "A river system modelling platform for Murray-Darling Basin, Australia." Journal of Hydroinformatics 15, no. 4 (March 29, 2012): 1109–20. http://dx.doi.org/10.2166/hydro.2012.153.
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Global climate change and local development make water supply one of the most vulnerable sectors in Australia. The Australian government has therefore commissioned a series of projects to evaluate water availability and the sustainable use of water resources in Australia. This paper discusses a river system modelling platform that has been used in some of these nationally significant projects. The platform consists of three components: provenance, modelling engine and reporting database. The core component is the modelling engine, an agent-based hydrological simulation system called the Integrated River System Modelling Framework (IRSMF). All configuration information and inputs to IRSMF are recorded in the provenance component so that modelling processes can be reproduced and results audited. The reporting database is used to store key statistics and raw output time series data for selected key parameters. This river system modelling platform has for the first time modelled a river system at the basin level in Australia. It provides practitioners with a unique understanding of the characteristics and emergent behaviours of river systems at the basin level. Although the platform is purpose-built for the Murray-Darling Basin, it would be easy to apply it to other basins by using different river models to model agent behaviours.
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Forbes, Jamin P., Charles R. Todd, Lee J. Baumgartner, Robyn J. Watts, Wayne A. Robinson, Aldo S. Steffe, Jeff J. Murphy, Martin W. Asmus, and Jason D. Thiem. "Simulation of different fishery regulations to prevent population decline in a large freshwater invertebrate, the Murray crayfish (Euastacus armatus)." Marine and Freshwater Research 71, no. 8 (2020): 962. http://dx.doi.org/10.1071/mf19109.
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Globally, overharvest contributes to population declines of fish and invertebrates. Quantifying the effects of fishing and associated harvest is essential to preventing such declines. Murray crayfish Euastacus armatus exhibit slow growth and late age at maturity, and were historically abundant in Australia’s Murray–Darling Basin, but river regulation, pollution and overfishing have reduced their range and abundance. Diminished recreational fisheries still exist, but data to quantify catch, effort and harvest are not available to inform management decisions. We used a population model to assess the status of a harvested Murray crayfish population, informed by data collected from a fishery-dependant survey. Quantitative fisher surveys were undertaken in the Murrumbidgee River during the 2012 Murray crayfish open season (May–August inclusive). Shortly after the surveys, and in light of fishery-independent data that indicated a Murray crayfish decline, the crayfish recreational fishery was spatially reduced and shortened to a 3-month season (June–August), bag limits were reduced and size limits were changed from a minimum length limit of 90mm to a harvest-slot length limit (HSLL) of 100–120mm. Modelling of the Murray crayfish population indicated it was most likely to be relatively small with a mean population size of 2777 individuals and affected by a high rate of crayfish harvest (harvest probability 0.4), indicating vulnerability to further decline should fishing effort and harvest persist. The population model was used to assess the regulation change to a HSLL, with the results supporting the regulation change and indicating that implementation of the HSLL would stabilise the population, albeit over many years. This study demonstrates that empirical data and population modelling are crucial to inform fishery regulations for threatened species.