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1
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.
2
Tibby, John, Deborah Haynes, and Kerri Muller. "The predominantly fresh history of Lake Alexandrina, South Australia, and its implications for the Murray–Darling Basin Plan: a comment on Gell (2020)." Pacific Conservation Biology 26, no. 2 (2020): 142. http://dx.doi.org/10.1071/pc19039.
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The pre-European settlement state of Lake Alexandrina, a lake system at the mouth of the River Murray has been the subject of some debate. Fluin et al. (2007) concluded on the basis of diatom evidence from sediment cores that ‘Marine water indicators were never dominant in Lake Alexandrina’. In a report to the South Australian Government, Fluin et al. (2009) stated, consistent with the earlier research, that ‘There is no evidence in the 7000 year record of substantial marine incursions into Lake Alexandrina’. Gell (2020) has argued both that Fluin et al. (2009) is in error and claims that it, and Sim and Muller’s (2004) book that describes early European settler accounts of the lake being fresh, underpin water provisions for Lake Alexandrina under the Murray–Darling Basin Plan. This response demonstrates that all these claims are untrue. Of the three diatom species suggested by Gell (2020) to be indicators of marine waters, Thalassiosira lacustris grows in the freshwater River Murray today, Cyclotella striata was never more than a minor component of the diatom flora and Paralia sulcata has not been detected in the lake in over 3000 years. Water provisions for Lake Alexandrina under The Basin Plan are founded on contemporary environmental water requirements and achievement of agreed socio-ecological-economic objectives, rather than the history of the lake. Nevertheless, the aim to maintain the lake as a freshwater ecosystem under The Murray–Darling Basin Plan is consistent with its history.
3
Bower, Deborah S., Clare E. Death, and Arthur Georges. "Ecological and physiological impacts of salinisation on freshwater turtles of the lower Murray River." Wildlife Research 39, no. 8 (2012): 705. http://dx.doi.org/10.1071/wr11214.
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Context The increasing intensity and extent of anthropogenically mediated salinisation in freshwater systems has the potential to affect freshwater species through physiological and ecological processes. Determining responses to salinisation is critical to predicting impacts on fauna. Aims We aimed to quantify the response of wild-caught turtles from freshwater lakes that had become saline in the lower Murray River catchment. Methods Plasma electrolytes of all three species of freshwater turtle from South Australia were compared among two freshwater sites (Horseshoe Lagoon and Swan Reach), a brackish lake (Lake Bonney) and a saline lake (Lake Alexandrina). Key results Chelodina longicollis, C. expansa and Emydura macquarii from a brackish lake had higher concentrations of plasma sodium and chloride than those from freshwater habitats. However, osmolytes known to increase under severe osmotic stress (urea and uric acid) were not elevated in brackish sites. Turtles from the highly saline lake were colonised by an invasive marine worm which encased the carapace and inhibited limb movement. Conclusions Freshwater turtles in brackish backwaters had little response to salinity, whereas the C. longicollis in a saline lake had a significant physiological response caused by salt and further impacts from colonisation of marine worms. Implications Short periods of high salinity are unlikely to adversely affect freshwater turtles. However, secondary ecological processes, such as immobilisation from a marine worm may cause unexpected impacts on freshwater fauna.
4
Surdu, C. M., C. R. Duguay, and D. Fernández Prieto. "Evidence of recent changes in the ice regime of lakes in the Canadian High Arctic from spaceborne satellite observations." Cryosphere Discussions 9, no. 6 (November 17, 2015): 6223–74. http://dx.doi.org/10.5194/tcd-9-6223-2015.
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Abstract. Arctic lakes, through their ice cover phenology, are a key indicator of climatic changes that the high-latitude environment is experiencing. In the case of lakes in the Canadian Arctic Archipelago (CAA), many of which are ice covered more than ten months per year, warmer temperatures could result in ice regime shifts. Within the dominant polar-desert environment, small local warmer areas have been identified. These relatively small regions – polar oases – with longer growing seasons, greater biological production and diversity, are confined from the surrounding barren polar desert. The ice regimes of 11 lakes located in both polar-desert and polar-oasis environments, with surface areas between 4 and 542 km2, many of unknown bathymetry, were documented. In order to investigate the response of ice cover of lakes in the CAA to climate conditions during recent years, a 15-year time series (1997–2011) of RADARSAT-1/2 ScanSAR Wide Swath, ASAR Wide Swath and Landsat acquisitions were analysed. Results show that melt onset (MO) occurred earlier for all observed lakes. With the exception of Lower Murray Lake, all lakes experienced earlier summer-ice minimum and water-clear-of-ice dates (WCI), with greater changes being observed for polar-oasis lakes (9–24 days earlier WCI dates for lakes located in polar oases and 2–20 days earlier WCI dates for polar-desert lakes). Additionally, results suggest that some lakes may be transitioning from a perennial/multiyear to a seasonal ice regime, with only a few lakes maintaining a multiyear ice cover on occasional years. Aside Lake Hazen and Murray Lakes that preserved their ice cover during the summer of 2009, no residual ice was observed on any of the other lakes from 2007 to 2011.
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Surdu, Cristina M., Claude R. Duguay, and Diego Fernández Prieto. "Evidence of recent changes in the ice regime of lakes in the Canadian High Arctic from spaceborne satellite observations." Cryosphere 10, no. 3 (May 10, 2016): 941–60. http://dx.doi.org/10.5194/tc-10-941-2016.
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Abstract. Arctic lakes, through their ice cover phenology, are a key indicator of climatic changes that the high-latitude environment is experiencing. In the case of lakes in the Canadian Arctic Archipelago (CAA), many of which are ice covered more than 10 months per year, warmer temperatures could result in ice regime shifts. Within the dominant polar-desert environment, small local warmer areas have been identified. These relatively small regions – polar oases – with longer growing seasons and greater biological productivity and diversity are secluded from the surrounding barren polar desert. The ice regimes of 11 lakes located in both polar-desert and polar-oasis environments, with surface areas between 4 and 542 km2, many of unknown bathymetry, were documented. In order to investigate the response of ice cover of lakes in the CAA to climate conditions during recent years, a 15-year time series (1997–2011) of RADARSAT-1/2 ScanSAR Wide Swath, ASAR Wide Swath, and Landsat acquisitions were analyzed. Results show that melt onset occurred earlier for all observed lakes. With the exception of Lower Murray Lake, all lakes experienced earlier summer ice minimum and water-clear-of-ice (WCI) dates, with greater changes being observed for polar-oasis lakes (9–24 days earlier WCI dates for lakes located in polar oases and 2–20 days earlier WCI dates for polar-desert lakes). Additionally, results suggest that some lakes may be transitioning from a perennial/multiyear to a seasonal ice regime, with only a few lakes maintaining a multiyear ice cover on occasional years. Aside Lake Hazen and Murray Lakes, which preserved their ice cover during the summer of 2009, no residual ice was observed on any of the other lakes from 2007 to 2011.
6
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.
7
Gell, Peter A. "Watching the tide roll away – contested interpretations of the nature of the Lower Lakes of the Murray Darling Basin." Pacific Conservation Biology 26, no. 2 (2020): 130. http://dx.doi.org/10.1071/pc18085.
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The Murray Darling Basin Plan (Murray Darling Basin Authority 2012) represents the largest investment by government in an Australian environmental management challenge and remains highly conflicted owing to the contested allocation of diminishing water resources. Central to the decision to reallocate consumptive water to environmental purposes in this Plan was the case made to maintain the freshwater character of two lakes at the terminus of the Murray Darling Basin, in South Australia. This freshwater state was identified as the natural condition on the basis of selected anecdotal evidence and was enshrined in the site’s listing under the Ramsar Convention. The commitment to the freshwater state was challenged under drought when sea water was seen as a means of averting acidification when low river flows risked the exposure of sulfidic sediments. Independent evidence from water quality indicators (diatoms) preserved in lake sediment records, however, attested to an estuarine, albeit variable, condition before the commissioning of near-mouth barrages in 1940. This interpretation for a naturally estuarine history, published after peer review, was overlooked in a report to the South Australian government, which argued, without the provision of new evidence from the lakes, that they were fresh for their entire history. This revised interpretation is widely cited in the scientific literature, government reports and online discussion and underpins a watering strategy aimed at a freshwater future for the Lower Lakes. The allocation of large volumes of fresh water to achieve this condition presents significant difficulties owing to the highly contested nature of water use across the Basin.
8
Gell, Peter A. "Corrigendum to: Watching the tide roll away – contested interpretations of the nature of the Lower Lakes of the Murray Darling Basin." Pacific Conservation Biology 26, no. 2 (2020): 211. http://dx.doi.org/10.1071/pc18085_co.
Full textAbstract:
The Murray Darling Basin Plan (Murray Darling Basin Authority 2012) represents the largest investment by government in an Australian environmental management challenge and remains highly conflicted owing to the contested allocation of diminishing water resources. Central to the decision to reallocate consumptive water to environmental purposes in this Plan was the case made to maintain the freshwater character of two lakes at the terminus of the Murray Darling Basin, in South Australia. This freshwater state was identified as the natural condition on the basis of selected anecdotal evidence and was enshrined in the site's listing under the Ramsar Convention. The commitment to the freshwater state was challenged under drought when sea water was seen as a means of averting acidification when low river flows risked the exposure of sulfidic sediments. Independent evidence from water quality indicators (diatoms) preserved in lake sediment records, however, attested to an estuarine, albeit variable, condition before the commissioning of near-mouth barrages in 1940. This interpretation for a naturally estuarine history, published after peer review, was overlooked in a report to the South Australian government, which argued, without the provision of new evidence from the lakes, that they were fresh for their entire history. This revised interpretation is widely cited in the scientific literature, government reports and online discussion and underpins a watering strategy aimed at a freshwater future for the Lower Lakes. The allocation of large volumes of fresh water to achieve this condition presents significant difficulties owing to the highly contested nature of water use across the Basin.
9
Bowling, Lee, Darren Baldwin, Chester Merrick, John Brayan, and Jared Panther. "Possible drivers of a Chrysosporum ovalisporum bloom in the Murray River, Australia, in 2016." Marine and Freshwater Research 69, no. 11 (2018): 1649. http://dx.doi.org/10.1071/mf18014.
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A major bloom of Chrysosporum ovalisporum occurred in ~2360km of the Murray–Edward–Wakool River System, Australia, during the 2016 austral summer and autumn. Several potential causes were investigated. Although summer air temperatures were among the hottest on record, no significant relationships were found between meteorological factors and bloom abundance. Instead, a weak but significant relationship was found between surface water temperature and bloom abundance downstream of Lake Hume, because the hot weather is likely to have led to higher water temperatures promoting bloom development. Releases of cold water inflows into Lake Hume from its Murray River arm may have stimulated upwelling of nutrient-rich deeper water, promoting the establishment of the bloom in that lake. Total nitrogen and total phosphorus concentrations were within the mesoeutrophic range and significantly related to bloom abundance, although some nutrient would be contained within cyanobacterial cells. During peak bloom abundance, pH was above 8.5 at one site. One unusual feature was that the bloom occurred in very dilute water, at electrical conductivities of 40–50 µScm–1. However, this does not appear to have affected carbon uptake and photosynthesis at high pH. Further blooms may occur if similar hot summers occur in future.
10
Zhang, Kun-Cheng, and Shu-Qing Yang. "Downstream Water Management Strategy in Murray–Darling Basin to Improve Adelaide’s Water Quality and Agricultural Output — Feasibility Analysis of a Dual-Purpose Coastal Reservoir." International Journal of Ocean and Coastal Engineering 02, no. 03n04 (September 2019): 1940004. http://dx.doi.org/10.1142/s2529807019400049.
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Australia is the driest country in the world, and the lower Murray–Darling Basin and Adelaide have experienced extreme water scarcity crisis, especially during the Millennium Drought (2000–2010). Many counter measures have been proposed or implemented like desalination plants and water buyback, etc., some progress has been made, but far away from a complete solution. Different from existing measures, this research aims at using coastal reservoir technology to shift from upstream water development to downstream development, in order to solve a series of water supply and ecological environment problems by redesigning a coastal reservoir in the downstream area. It is suggested that high-quality water is stored in a “coastal reservoir” inside the Alexandrina Lake for Adelaide’s water supply. The lake water outside the “coastal reservoir” is used for agricultural development. A preliminary feasibility study was conducted in terms of water quantity and water quality, river’s environmental flow and agricultural output. The results show that if a small size (550–630[Formula: see text]GL) coastal reservoir was created inside the Lake Alexandrina in the mouth of Murray River, the Adelaide’s water supply could be secured and its water quality be improved even during droughts like the Millennium Drought. Besides, if the agricultural development is concentrated around the lake, its water demand can be fully met from the lake, rather than the river, thus the agricultural development has little negative impacts on the river’s ecosystem, it is a win-win solution for agricultural development and river ecosystem. It is suggested that Australian government should provide stimulus package for upstream farmers to relocate to areas around the lake.
11
Wedderburn, S. D., and T. C. Barnes. "Piscivory by alien redfin perch (Perca fluviatilis) begins earlier than anticipated in two contrasting habitats of Lake Alexandrina, South Australia." Australian Journal of Zoology 64, no. 1 (2016): 1. http://dx.doi.org/10.1071/zo15083.
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Redfin perch (Perca fluviatilis) introduced to the Southern Hemisphere has contributed to the decline or localised extirpations of native fishes, principally due to predation. It has been widely recorded in the Murray–Darling Basin, south-eastern Australia, since the 1920s but the ecological consequences are largely undetermined. The purpose of this study was to examine the diet of juvenile redfin perch in Lake Alexandrina to assess its potential impacts on native biota in two distinct habitats (channel and lake). We proposed that the broad dietary composition of juvenile redfin perch matches that of its natural range (small decapods and insects). Most juvenile redfin perch with prey items in their guts, however, had consumed native fish. There was variability in the diet of redfin perch between the channel and lake where gudgeons and gobies, respectively, were targeted. Unexpectedly, otolith ageing revealed that the redfin perch were larger and shifted to piscivory at a much younger age compared with populations in its native range. Among other ecological issues, the findings are pertinent to threatened small-bodied fish populations in the Murray–Darling Basin. More broadly, they suggest that a generalist feeding behaviour can lead to the early onset of piscivory in alien fish populations.
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Bowles, Karl C., Simon C. Apte, William A. Maher, Matthew Kawei, and Ross Smith. "Bioaccumulation and biomagnification of mercury in Lake Murray, Papua New Guinea." Canadian Journal of Fisheries and Aquatic Sciences 58, no. 5 (May 1, 2001): 888–97. http://dx.doi.org/10.1139/f01-042.
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The bioaccumulation of mercury in the food webs incorporating the major piscivorous fish species of Lake Murray, Papua New Guinea, has been characterised. Methylmercury concentrations increased with trophic level and the proportion of total mercury present as methylmercury increased from <1% in plants to 94% in piscivorous fish. Methylmercury bioaccumulation factors (BAFs) were similar to those found in temperate environments, with a typical increase of 1 log unit between planktivore and piscivore trophic levels. The greatest bioaccumulation of methylmercury occurred between seston and the water column (log BAF of 5.36). The bioaccumulation of mercury to levels of regulatory concern by the lake's piscivores was attributable to the biomagnification power of the plankton-based food chain comprising four trophic levels (phytoplankton, zooplankton, planktivore, piscivore) rather than any elevated concentrations of mercury in waters or sediments. The methylmercury concentrations of individual piscivores were positively correlated with both trophic position, as indicated by δ15N measurements, and fish size. Stable-isotope measurements were used to identify fish species where dietary changes occurring with age significantly augmented age-related bioaccumulation of mercury.
13
Twidale, C. R., and J. A. Bourne. "Course of the lower River Murray in South Australia: effects of underprinting and neotectonics?" Proceedings of the Royal Society of Victoria 121, no. 2 (2009): 207. http://dx.doi.org/10.1071/rs09207.
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The change in direction of the River Murray from westerly to southerly at North West Bend has been attributed to faulting or warping, but no appropriate structure has been located in the country rock coincident with the river course. Yet the angularity and the straightness of major sectors argue structural control. The plan course of the Murray downstream from Morgan is attributed to underprinting from basement fractures following the Middle Miocene but prior to the Late Pliocene. Uplift of the Marmon Jabuk structure superimposed on the effects of underprinting accounts for major departures from the SSW trend downstream from North West Bend, as well as the impounding of Lake Bungunnia. The upper shallow section of the valley-in-valley form was shaped at a time of higher baselevel in the Middle-Late Tertiary. The lower section is the present Gorge. The valley floor was lowered probably by subterranean solution and flow followed by collapse of the cavern roofs. Regression of the River at times of lower sea level caused the breach of the Marmon Jabuk blockage and the draining of Lake Bungunnia.
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Musyl, MK, and CP Keenan. "Population genetics and zoogeography of Australian freshwater golden perch, Macquaria ambigua (Richardson 1845) (Teleostei: Percichthyidae), and electrophoretic identification of a new species from the Lake Eyre basin." Marine and Freshwater Research 43, no. 6 (1992): 1585. http://dx.doi.org/10.1071/mf9921585.
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Populations of golden perch (Macquaria ambigua) were sampled from both sides of the Great Dividing Range (GDR): from the Murray-Darling drainage basin (Murray R., L. Keepit and Condamine R.), the L. Eyre internal drainage basin (Barcoo R. and Diamantina R.), and the internal drainage basin of the Bulloo R.-all to the west of the GDR-and from the Fitzroy drainage basin (Dawson R. and Nogoa R.) east of the GDR. Starch-gel and polyacrylamide electrophoresis of 12 enzyme systems plus two general muscle proteins was used to estimate the genetic variation within and between populations. Of the 18 presumed genetic loci examined, nine were either polymorphic at the P0.99 criterion level or exhibited fixed allelic differences between some of the populations. Within the Murray-Darling drainage basin, there was little indication of heterogeneity. Contingency Χ2 analyses of allelic distributions among drainage basins indicated significant levels of heterogeneity at six variable loci. The isolated L. Eyre population exhibited diagnostic alleles at four loci when compared with the Murray- Darling and Fitzroy populations. The genetic distance of the L. Eyre population (Nei's D=0.23) from these two populations indicates that the L. Eyre golden perch is most probably a previously unrecognized allopatric species. The level of divergence (0 = 0.06) between Fitzroy and Murray-Darling golden perch indicates differentiation at the subspecies level, with no fixed differences observed between these two populations. Finally, golden perch from the Bulloo R. represent either (i) an intermediate evolutionary unit between the presumed ancestral L. Eyre population and the derived Murray-Darling and Fitzroy populations or (ii) a complex hybrid between these populations. Average gene-flow statistics, FST = 0.760 and Nem=0.08, suggest that the populations in each of the four basins can be regarded as separate gene pools that have been isolated for different, and considerable, periods of time.
15
Stone, Tim. "Last glacial cycle hydrological change at Lake Tyrrell, southeast Australia." Quaternary Research 66, no. 1 (July 2006): 176–81. http://dx.doi.org/10.1016/j.yqres.2006.03.007.
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AbstractLake Tyrrell is the largest playa in the Murray Basin of southeast Australia. Optical dating of transverse dune (lunette) sediments extends the lake's radiocarbon chronology to the last interglacial period. The highest lake level was attained 131,000 ± 10,000 yr ago, forming Lake Chillingollah, a megalake that persisted until around 77,000 ± 4000 yr ago. Pedogenesis of its sandy lunette continued until buried by a silty clay lunette deflated from the lake floor 27,000 ± 2000 yr ago. The dated soil-stratigraphic units correlate with the upper Tyrrell Beds and contain evidence that humans visited the lakeshore before 27,000 yr ago. The Lake Chillingollah megalake was synchronous with very high lake levels in monsoon-dominated Australia, yet it was not influenced by tropical monsoon systems. It was filled instead by increased winter rainfall from westerly low-pressure fronts. Greater effective precipitation across Australia is evident, the result of a weakened subtropical high-pressure zone.
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Job, Thomas, Dan Penny, Bree Morgan, Quan Hua, Patricia Gadd, and Atun Zawadzki. "Multi-stage Holocene evolution of the River Murray Estuary, South Australia." Holocene 31, no. 1 (October 8, 2020): 50–65. http://dx.doi.org/10.1177/0959683620961487.
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The River Murray Estuary, South Australia exhibits a morphology typical of a wave-dominated estuary and comprises two large, shallow central basin lakes – Lakes Alexandrina and Albert. Contested interpretations of the estuary’s limnological history and uncertainty surrounding the sustainability of current basin water usage practice warrant a robust investigation into how the system has evolved. Here we combine lithostratigraphic, geochemical and sedimentological evidence from a transect of sediment cores to reconstruct the sediment infill history of the system. We uncover multiple stages of sediment infill over the history of the system, associated with (1) the low gradient morphology of the estuary and lower river channel, (2) the mid- to late-Holocene sea-level regression and (3) anthropogenic modifications to the fluvio-estuarine system. We show that while estuarine conditions in the system were fully established during the mid-Holocene highstand (~6.4 kyr BP), central basin facies sedimentation was focussed further inland before prograding with the lowering of base level and shifting of tidal influence as sea-level fell. Central basin facies sedimentation within northern Lake Albert occurred from 5.4 to 4.0 cal kyr BP at ~0.25 cm yr-1. The uppermost accumulation of this unit was eroded by continued reduction in base level until sea-level regression concluded at 3.5 cal kyr BP. Barrage and weir installation (1940 CE) re-initiated and expanded central basin facies sedimentation in the estuary (~0.32 cm yr-1). Recently deposited sediments exhibit geochemical markers of increased trophy and more frequent acid sulfate soil acidification, exposing human impacts on the estuary.
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Osborne, PL, JH Kyle, and MS Abramski. "Effects of seasonal water level changes on the chemical and biological limnology of Lake Murray, Papua New Guinea." Marine and Freshwater Research 38, no. 3 (1987): 397. http://dx.doi.org/10.1071/mf9870397.
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Lake Murray, with a surface area of 647 km2 and a high-water convoluted shoreline 2038 km long, is the largest lake in Papua New Guinea and exhibits marked seasonal fluctuations in water level. The fall in water level of 4 m between April and December 1982 was accompanied by a marked rise in pH (from 5.3 to 9.6), conductivity (from 12 to 100 �S cm-1), total hardness (from 80 to 400�M) and filterable residue (from 11 to 45 mg l-1). In November 1982, maximum production of phyto-planktonic oxygen was 1120 mg O2 m-3 h-1 at the surface but declined sharply with depth because of light attenuation by suspended solids. It was much higher than that recorded in April 1982 (250 mg O2 m-3 h-1). The long shoreline and the shallowness of the lake result in a very large littoral zone. Diurnal variation in oxygen concentrations during periods of high water level indicated that the littoral zone is a very productive area of the lake. However, when the water level is low, the lake is surrounded by a wide expanse of barren mud.
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Fusco, Diana A., Matthew C. McDowell, Graham Medlin, and Gavin J. Prideaux. "Fossils reveal late Holocene diversity and post-European decline of the terrestrial mammals of the Murray–Darling Depression." Wildlife Research 44, no. 1 (2017): 60. http://dx.doi.org/10.1071/wr16134.
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Context Establishing appropriate faunal baselines is critical for understanding and abating biodiversity declines. However, baselines can be highly reliant on historical records that come from already disturbed ecosystems. This is exemplified in the Murray–Darling Depression bioregion of Australia, where European settlement (and accompanying marked land-management changes and the introduction of many species) triggered rapid declines and losses of native species, often before their documentation. Aims We aim to establish the mammal fauna present when Europeans settled the Murray Mallee and Murray–Darling Depression bioregion and determine the extent of mammal loss since European settlement. Methods We describe a dated vertebrate assemblage from Light’s Roost in the lower Murray Mallee region of South Australia. We compare our data with those of modern fauna surveys and historical records to document the extent of change in the mammal fauna since European settlement. Key results Radiocarbon ages showed that the assemblage was accumulating, at a minimum, within an interval from 1900 to 1300 years ago. Since this time, the Murray–Darling Depression has lost half of its flightless terrestrial mammals. Species lost include the mulgara (Dasycercus blythi/cristicauda), which places this taxon within only 40km of Lake Alexandrina, the hitherto-disputed type locality for D. cristicauda. Fossils provided the principal evidence for nearly half of the Murray Mallee fauna and over three-quarters of the fauna are represented in the fossil record. Conclusions Late Holocene assemblages provide important archives of species biogeography and diversity. Our revised faunal baseline indicated that the pre-European fauna of the Murray–Darling Depression was more diverse than hitherto understood and its reduction appears largely caused by the impacts of European settlement. Implications Baselines for species distributions derived from historical records and modern faunal surveys are likely to be incomplete and warrant revision, particularly for smaller and more cryptic species. Deficiencies in regional records mask the extent of mammal declines caused by European colonisation and associated agricultural practices, and thus vulnerability to anthropogenic disturbance.
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Avery, Cheryl. "‘Incentive to vision’: the Emma Lake Art Camp." Art Libraries Journal 24, no. 3 (1999): 19–24. http://dx.doi.org/10.1017/s0307472200019581.
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With the opening of its Murray Point Summer School of Art at Emma Lake in 1936, the University of Saskatchewan became the first Canadian university to establish an outdoor art school. Emma Lake is in northern Saskatchewan, and every attempt was made by the University to preserve the virgin forest in the area where the classes were held. Although primarily developed for the benefit of Saskatchewan residents, the workshops became nationally and internationally known, and acclaimed painters, sculptors and critics from across Canada, Europe and the United States made the trip north. For over twenty years students attending the school produced an annual scrapbook documenting their experience; the photographs and illustrations from those yearbooks provide both interesting social commentary and excellent documentation of a learning environment students considered ‘rich, deep and significant’.
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Matveev, V. F., and L. K. Matveeva. "Seasonal succession and long-term stability of pelagic community in a productive reservoir." Marine and Freshwater Research 56, no. 8 (2005): 1137. http://dx.doi.org/10.1071/mf04289.
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In Lake Hume, a reservoir located in an active agricultural zone of the Murray River catchment, Australia, time series for the abundances of phytoplankton and zooplankton taxa, monitored from 1991 through to 1996, were stationary (without trends), and plankton taxonomic composition did not change. This indicated ecosystem resilience to strong fluctuations in reservoir water level, and to other potential agricultural impacts, for example eutrophication and pollution. Although biological stressors such as introduced fish and invertebrate predators are known to affect planktonic communities and reduce biodiversity in lakes, high densities of planktivorous stages of alien European perch (Perca fluviatilis) and the presence of carp (Cyprinus carpio) did not translate into non-stationary time series or declining trends for plankton in Lake Hume. However, the seasonal successions observed in the reservoir in different years did not conform well to the Plankton Ecology Group (PEG) model. Significant deviations of the Lake Hume successional pattern from the PEG model included maxima for phytoplankton abundance being in winter and the presence of a clear water phase without large zooplankton grazers. The instability of the water level in Lake Hume probably causes the dynamics of most planktonic populations to be less predictable, but did not initiate the declining trends that have been observed in some other Australian reservoirs. Both the PEG model and the present study suggest that hydrology is one of the major drivers of seasonal succession.
21
Chessman, BC. "Diet of the Murray Turtle, Emydura-Macquarii (Gray) (Testudines, Chelidae)." Wildlife Research 13, no. 1 (1986): 65. http://dx.doi.org/10.1071/wr9860065.
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Examination of the stomach contents of 122 E. macquarii from the Murray River, Lake Boga and other waters in northern Victoria and southern New South Wales showed that this species is an opportunistic omnivore. In order of decreasing importance the main food types were filamentous algae, vertebrate (mainly fish) carrion, detritus, periphyton (including sponges), mobile aquatic invertebrates, aquatic macrophytes and terrestrial invertebrates. There was a degree of dietary shift with turtle size, small specimens containing more detritus and periphyton and less filamentous algae, macrophytes and carrion than bigger ones. The diets of mature males and females did not differ appreciably. Diel changes in stomach content volumes indicated that E. macquarii feeds mainly during the daytime.
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Codd, GA, DA Steffensen, MD Burch, and PD Baker. "Toxic blooms of cyanobacteria in Lake Alexandrina, South Australia — Learning from history." Marine and Freshwater Research 45, no. 5 (1994): 731. http://dx.doi.org/10.1071/mf9940731.
Full textAbstract:
Early accounts by European explorers and settlers of South Australia contain numerous references to scums or discoloured water that are consistent with cyanobacterial blooms. Documented reports refer back to at least 1853. The first detailed scientific account of toxic cyanobacteria appeared in 1878. In a perceptive and prescient paper in Nature, the Adelaide assayer and chemist George Francis reported on stock deaths at Milang on the shores of Lake Alexandrina in South Australia. Francis attributed the deaths to the ingestion and toxicity of scums of the cyanobacterium Nodularia spumigena. Reports of cyanobacterial blooms, scums and associated problems in Lake Alexandrina and in the River Murray between about 1851 and 1888 are discussed and comparisons are made with the reactions to blooms a century later.
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Fitzsimmons, Kathryn E., Caroline Spry, and Nicola Stern. "Holocene and recent aeolian reactivation of the Willandra Lakes lunettes, semi-arid southeastern Australia." Holocene 29, no. 4 (January 29, 2019): 606–21. http://dx.doi.org/10.1177/0959683618824790.
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The Willandra Lakes in semi-arid southeastern Australia provide some of the most continuous combined palaeoenvironmental and archaeological records on the continent. These are best preserved within the transverse shoreline (lunette) dunes on their downwind margins. Following final lake retreat c. 15 ka avulsion of the dominant fluvial inflow eastwards, the Willandra lunettes periodically reactivated, experiencing erosion, aeolian redeposition and alluvial sheetwash. These reworked sedimentary archives reflect regional climatic conditions rather than those of the entire catchment. Yet the focus of most study in the region to date has remained on the late Pleistocene. The general paucity of Holocene data has contributed to a perception that people largely abandoned the area in favour of the perennial Murray and Darling Rivers to the south and west. Our study reconstructs past geomorphological conditions and patterns of human mobility in adjacent Lakes Mungo and Durthong over the last c. 15 ka subsequent to final lake retreat, including the most recent 150 years since Europeans established pastoralism in the region. Our data show that Indigenous people did not abandon the area as previously assumed, but developed effective strategies for responding to the changed environmental conditions. Final lake retreat transitioned into a phase of aeolian accumulation c. 15–12 ka, indicating locally dry conditions. Subsequent aeolian reactivation peaked during arid phases experiencing less rainfall in the early Holocene and twice in the most recent 1000 years prior to European settlement in the area. Alluvial sheetwash was deposited onto lake floors during the mid-Holocene, and again in the early decades of European settlement. Aeolian reactivation, likely driven by European pastoral activities, increases in the most recent 150 years. Our study underscores the necessity of integrating geomorphological and archaeological investigations over landscape scales in order to optimise our understanding of interactions between people and their environment through time.
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Baker, PD, and AR Humpage. "Toxicity associated with commonly occurring cyanobacteria in surface waters of the Murray-Darling Basin, Australia." Marine and Freshwater Research 45, no. 5 (1994): 773. http://dx.doi.org/10.1071/mf9940773.
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Surveys of cyanobacterial blooms were made over four consecutive summer seasons (1990-93) in surface waters of the Murray-Darling Basin in south-eastern Australia to determine the incidence and geographic distribution of toxicity associated with a range of recognized taxa.<P. In all, 231 field samples and 143 cultured isolates, representing 13 genera, were tested for toxicity by intra-peritoneal mouse bioassay. Toxicity was recorded in 42% of all field samples and was expressed quantitatively on the basis of both dry weight and cell number. Anabaena was the most abundant genus in blooms occurring in riverine and wetland habitats, and Anabaena circinalis was prominent in all field samples that were neurotoxic. Neurotoxicity was not demonstrated in any other species of Anabaena, or in any other genus, in both field and cultured material. Assays for anatoxin-a were negative, and symptoms of neurotoxicity in mice were not consistent with those reported elsewhere for anatoxin-a(s). Hepatotoxic blooms occurred predominantly in standing waters and were invariably caused by Microcystis aeruginosa f. aeruginosa throughout the greater part of the Basin. Toxic blooms of Nodularia spumigena were recorded only in Lake Aiexandrina and Lake Albert at the mouth of the River Murray. Hepatotoxicity was also demonstrated in strains of Cylindrospermopsis raciborskii, which was previously recognized in Australia only as a subtropical cyanobacterium.
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KARABANOV, DMITRY P., EUGENIYA I. BEKKER, RUSSELL J. SHIEL, and ALEXEY A. KOTOV. "Invasion of a Holarctic planktonic cladoceran Daphnia galeata Sars (Crustacea: Cladocera) in the Lower Lakes of South Australia." Zootaxa 4402, no. 1 (March 27, 2018): 136. http://dx.doi.org/10.11646/zootaxa.4402.1.6.
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We found a Holarctic microcrustacean Daphnia galeata Sars, 1863 (Cladocera: Daphniidae) in the Lower Lakes of South Australia. This taxon was never detected in continental Australia before. Its identity was confirmed by the sequences of mitochondrial COI, 12S and 16S and nuclear 18S and 28S genes. A maximum likelihood tree from a dataset from combining 12S + 16S mitochondrial sequence and a split network of the COI haplotypes are provided, but resolution of both genes is not sufficient to reveal the exact region of the Holarctic from where D. galeata was introduced to Australia; the vector of its invasion also is unknown. We hypothesize that appearance of D. galeata in the Lower Lakes of the Murray River is related to a recent anthropogenic eutrophication of water bodies in this region, keeping in mind that examples of successful invasion of some European lakes by D. galeata after their eutrophication are well-known. We also hypothesize that establishment of this non-indigenous taxon populations in Australia might have a strong negative impact on native lake biota.
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Kemp, Justine, Lynda C. Radke, Jon Olley, Steve Juggins, and Patrick De Deckker. "Holocene lake salinity changes in the Wimmera, southeastern Australia, provide evidence for millennial-scale climate variability." Quaternary Research 77, no. 1 (January 2012): 65–76. http://dx.doi.org/10.1016/j.yqres.2011.09.013.
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Palaeosalinity records for groundwater-influenced lakes in the southwest Murray Basin were constructed from an ostracod-based, weighted-averaging transfer function, supplemented with evidence from Campylodiscus clypeus (diatom), charophyte oogonia, Coxiella striata (gastropod), Elphidium sp. (foraminifera), Daphniopsis sp. ephippia (Cladocera), and brine shrimp (Parartemia zietziana) faecal pellets, the δ18O of ostracods, and > 130 μm quartz sand counts. The chronology is based on optically stimulated luminescence and calibrated radiocarbon ages. Relatively wet conditions are marked by lower salinities between 9600 yr and 5700 yr ago, but mutually exclusive high- and low-salinity ostracod communities suggest substantial variability in effective precipitation in the early Holocene. A drier climate was firmly in place by 4500 yr and is marked at the groundwater-dominated NW Jacka Lake by an increase in aeolian quartz and at Jacka Lake, by a switch from surface-water to groundwater dominance. Short-lived, low-salinity events at 8800, 7200, 5900, 4800, 2400, 1300 and 400 yr are similar in timing and number to those recorded on Australia's southern continental shelf, and globally, and provide evidence for the existence of the ~ 1500-yr cycle in mainland southern Australia. We surmise that these are cool events associated with periodic equatorward shifts in the westerly wind circulation.
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Morton, R., and RB Cunningham. "Longitudinal profile of trends in salinity in the river Murray." Soil Research 23, no. 1 (1985): 1. http://dx.doi.org/10.1071/sr9850001.
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Statistical analyses have been performed on series of electrical conductivity (EC) measurements taken over the past 16 years from 8 stations on the River Murray to assess changes in salinity along the river and trends over time. Below Euston, N.S.W., salinity has generally increased over time, although the log-linear trends were statistically significant at only three stations: Red Cliffs, Morgan and Mannum. The increase in EC of over 1% p.a. at Red Cliffs was partly removed when it passed to Merbein, and we attribute this to the Lake Hawthorn salinity interception scheme. Both Morgan and Mannum showed increases of over 2% p.a., confirming the results of our earlier analysis of chloride data from Morgan, and current levels there are close to the desirable limit of 800 �S/cm. Thus major adverse effects can be anticipated if the rate of increase over the last 16 years is allowed to continue.
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Appleford, P., T. A. Anderson, and G. J. Gooley. "Reproductive cycle and gonadal development of Macquarie perch, Macquaria australasica Cuvier (Percichthyidae), in Lake Dartmouth and tributaries of the Murray - Darling Basin, Victoria, Australia." Marine and Freshwater Research 49, no. 2 (1998): 163. http://dx.doi.org/10.1071/mf97012.
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The gonadal development, reproductive cycle and growth of Macquarie perch, Macquaria australasica Cuvier, in Lake Dartmouth and selected tributaries of the Murray–Darling River Basin in south-eastern Australia were evaluated. Gonadosomatic index (GSI) and histological analysis were used to determine gonadal development and age and size at first maturity in the resident Lake Dartmouth population. GSI analysis was also used to determine age and size of Macquarie perch at first maturity in the inflowing Mitta Mitta River and other riverine populations within the Goulburn River catchment. Males appeared slightly smaller at first spawning than females at all sites; both sexes were fully mature at four years of age. Differences in size at first maturity were found between the lake and river populations; both males and females of river populations tended to mature at a much smaller size than the fish resident in the lake. Spawning occurred around November. Ovarian and testicular development in this species follows a pattern similar to that of other native Australian percichthyids. The implications for management of recreational fisheries based on minimum size regulations is discussed in relation to site-specific differences in growth rates and size of first maturity of fish.
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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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Law, B., and CA Urquhart. "Diet of the Large-footed Myotis Myotis Mcropus at A Forest Stream Roost in Northern New South Wales." Australian Mammalogy 22, no. 2 (2000): 121. http://dx.doi.org/10.1071/am00121.
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RECENT evidence indicates that the large-footed myotis Myotis macropus (previously Myotis adversus) is the sole representative of its genus in Australia (Cooper et al. in press). These are small bats that forage over pools of water in small streams, rivers and lakes, using large feet to trawl for prey along water surfaces (Dwyer 1970; Thompson and Fenton 1982). Little is known about their diet. Fish have been confirmed in the diet of M. macropus at a population that forages over a large lake, near Brisbane (Robson 1984). Unidentified insect material formed the bulk of the species? diet in Robson?s study. A small number of scats were also examined from M. macropus caught on the Murray River in South Australia (Jansen 1987). These contained fish remains and insects, particularly Chironominae (midges) and Culicidae (mosquitoes). We studied the diet of M. macropus at a forest stream to determine the importance of aquatic prey and thus to help guide management strategies for the species.
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Geddes, MC. "The role of turbidity in the limnology of Lake Alexandrina, River Murray, South Australia; comparisons between clear and turbid phases." Marine and Freshwater Research 39, no. 2 (1988): 201. http://dx.doi.org/10.1071/mf9880201.
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In the first months of 1981, the characteristically highly turbid Lake Alexandrina cleared somewhat so that turbidity dropped from a previous mean value (1975-1978) of 93 NTU to 9 NTU, the Secchi transparency and euphotic depth increased from previous means of 19 cm and 0.8 m to 72 cm and 3.1 m, and the light extinction coefficient fell from 6.54 to 1.2 In units m-1. Low flows in the River Murray, especially low contributions from the Darling River, and high salinity appeared to be the major factors responsible for the clearing. During the clear phase, nutrient levels fell, the normal summer peak of the ulotrichous green alga Planctonema lauterbornei failed to occur, there was a late summer-autumn bloom of blue greens especially Nodularia and Anabaena, and densities of the large microcrustaceans Boeckella triarticulata and Daphnia carinata were low. After flushing, the lake turbidity rose to previous high levels and over the period October 1981-April 1982 P. lauterbornei again dominated the phyto- plankton, chlorophyll a biomass reached 67 mg m-3, and the zooplankton community returned to its normal pattern of seasonality and abundance. The role of turbidity in controlling the physicochemical and biological conditions in the lake is discussed.
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Hammer, Michael P., Mark Adams, Peter J. Unmack, and Keith F. Walker. "A rethink on Retropinna: conservation implications of new taxa and significant genetic sub-structure in Australian smelts (Pisces:Retropinnidae)." Marine and Freshwater Research 58, no. 4 (2007): 327. http://dx.doi.org/10.1071/mf05258.
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The smelt genus Retropinna nominally includes three small (<150 mm) freshwater fish species endemic to south-eastern Australia and New Zealand. For the two Australian species, the broad range of R. semoni (Weber) on the mainland suggests some vulnerability to isolation and genetic divergence, whereas the apparent confinement of R. tasmanica McCulloch to Tasmania is curious if, as suspected, it is anadromous. Analyses of Australian material using allozyme electrophoresis show five genetically distinct species with contiguous ranges and no evidence of genetic exchange. Three occur along the eastern seaboard (including three instances of sympatry), another in coastal and inland south-eastern Australia and Tasmania, and a fifth species in the Lake Eyre Basin. There is no indication of a simple ‘tasmanica’ v. ‘semoni’ dichotomy, but instead a complex pattern involving discrete clusters for the Upper Murray plus Darling rivers, Lower Murray, Glenelg River and Tasmanian regions, with coastal western Victorian samples having varying affinity to these groups. The overall pattern is one of deep divergences among species and strong genetic sub-structuring within and provides a strong argument for extended studies to prepare for appropriate conservation measures.
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Martin, HA. "The Palaeovegetation of the Murray Basin, Late Eocene to Mid-Miocene." Australian Systematic Botany 6, no. 6 (1993): 491. http://dx.doi.org/10.1071/sb9930491.
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The principles of pollen dispersal and deposition show that the pollen spectrum is produced by the plants of the locality, with a little transported in from long distances. The 'locality' has a radius of no more than 500 m, and it could be much less. Adherence to these principles has allowed a detailed reconstruction of the palaeovegetation. Nothofagus grew throughout the Murray Basin, probably on the dry ground in the flood plain complex. Occasionally it was dominant, but most of the forests were mixed. The fusca-type flourished on well drained sites, especially in the north-east. The menziesii-type became prominent in the mid-Miocene, when the climate was becoming drier. The brassii-type was probably the only type in the deeper, swampier parts of the basin. Gymnosperms were intimately connected with the semi-swamp forest. Araucariaceae–Casuarinaceae forests formed a coastal zone around the Miocene marine incursion. Herbaceous fresh water swamps were found in the north-west, where they formed disjuncts from the swampy margin of Lake Frome. Myrtaceae was found throughout, sometimes abundantly, but eucalypts were rare. Geographic variation, changes through time and forest dynamics, including possibly one very rare modification after burning, are detailed.
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Stein, N., J. P. Grotzinger, J. Schieber, N. Mangold, B. Hallet, H. Newsom, K. M. Stack, et al. "Desiccation cracks provide evidence of lake drying on Mars, Sutton Island member, Murray formation, Gale Crater." Geology 46, no. 6 (April 16, 2018): 515–18. http://dx.doi.org/10.1130/g40005.1.
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Walker, K. F. "Reproductive phenology of river and lake populations of freshwater mussels (Unionida: Hyriidae) in the River Murray." Molluscan Research 37, no. 1 (July 18, 2016): 31–44. http://dx.doi.org/10.1080/13235818.2016.1206166.
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Zhisheng, An, J. M. Bowler, N. D. Opdyke, P. G. Macumber, and J. B. Firman. "Palaeomagnetic stratigraphy of Lake Bungunnia: Plio-pleistocene precursor of aridity in the murray basin, Southeastern Australia." Palaeogeography, Palaeoclimatology, Palaeoecology 54, no. 1-4 (May 1986): 219–39. http://dx.doi.org/10.1016/0031-0182(86)90126-4.
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Campbell, Cherie Joy, Fiona Linda Freestone, Richard P. Duncan, Will Higgisson, and Sascha Jade Healy. "The more the merrier: using environmental flows to improve floodplain vegetation condition." Marine and Freshwater Research 72, no. 8 (2021): 1185. http://dx.doi.org/10.1071/mf20303.
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Environmental flows are increasingly being used to restore degraded floodplain vegetation; however, the type of flow regime required for recovery to healthy condition can vary depending on the extent of degradation before restoration. Regulation of the River Murray has affected floodplain ecosystems at many locations, including Bottle Bend Reserve, in south-western New South Wales, Australia. Within Bottle Bend Reserve, tangled lignum (Duma florulenta) dominates sections of the higher floodplain elevations. Lignum is an important and widely distributed Australian shrub occurring in arid and semiarid river systems within the Murray–Darling and Lake Eyre Basins. In an effort to restore floodplain vegetation, three environmental flows were delivered to Bottle Bend Reserve between 2013 and 2016. Flows varied in magnitude, leading to a mosaic of different regimes across the area. Condition surveys were undertaken over 1 year, namely, before, during and after delivery of the September 2016 environmental flow. This study found that the greatest response occurred in lignum plants with no recent environmental water, although lignum plants with one or two recent environmental flows still responded relative to the control. Lignum was in a better condition at sites that received more environmental flows, demonstrating the value of increased frequency of flows in recovering vegetation health.
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Gooley, GJ. "Validation of the use of Otoliths to determine the ate and growth of Murray Cod, Maccullochella peelii (Mitchell) (Percichthyidae), in Lake Charlegrark, Western Victoria." Marine and Freshwater Research 43, no. 5 (1992): 1091. http://dx.doi.org/10.1071/mf9921091.
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The age and growth of Murray cod, Maccullochella peelii, in Lake Charlegrark, western Victoria, were determined by using otoliths from fish sampled by beach-seine and gill-net, or caught by anglers, between August 1978 and August 1982. Annulus formation was validated up to 11 + years by several methods. Otoliths were examined from hatchery-bred fish of known age (up to 4+ years) that had been stocked into local farm ponds. Analysis of incremental growth for all fish sampled from the lake indicated that the mean edge-growth ratio was lowest, and the percentage of otoliths with an annulus at the edge was highest, in October. A nominal birth date of 1 October was designated for the population to enable calculation of the absolute age for each fish. Age-composition data for those fish taken by gill-net and by anglers (up to 21 + years) revealed modal progression of strong year classes (1970 to 1973 inclusive) during the sampling period. Length-frequency data for those fish taken by beach-seine (up to 3 + years) revealed modal progression, on a seasonal basis, of two relatively strong year classes (1978 and 1979) during the sampling period. A von Bertalanffy growth curve was fitted to length and age data for all fish collected in the lake (no sex difference, P>O.05), and growth parameters were estimated for the population (L∞ = 695 mm). This curve did not adequately describe the growth of fish older than 11 + years because the majority of sampled fish (98.3%) were aged 11 + years or younger. The length-weight relationship for the population was determined by using data from all fish collected in the lake (no sex difference, P>0.05).
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Anderson, JR, AK Morison, and DJ Ray. "Age and growth of Murray Cod, Maccullochella peelii (Perciformes: Percichthyidae), in the Lower Murray-Darling Basin, Australia, from thin-sectioned Otoliths." Marine and Freshwater Research 43, no. 5 (1992): 983. http://dx.doi.org/10.1071/mf9920983.
Full textAbstract:
Transverse thin sections (0.5 mm thick) of sagittal otoliths from 290 Murray cod up to 1400 mm in total length and 47.3 kg in weight were used to establish the age and growth of cod in the lower Murray-Darling Basin, including comparisons of recent (1986-91) and past (1949-51) growth rates and growth in different waters. The maximum estimated age was 48 years. Quantitative and qualitative analysis of the seasonal changes in otolith marginal increments showed that annuli in fish of all ages were laid down each spring, and 1 October was assigned as the birthday. The thin-sectioning method was validated by comparing age estimates for 55 Murray cod from Lake Charlegrark (age 0-21 years), which had been validated by using burnt and polished half-otoliths. The new method had an accuracy of 96.4% and it offers major advantages in ease of preparation, reading, and batch-handling of large numbers of otoliths. The precision of the method, estimated as an average error for four readers, was 5.4% (3.0% after ignoring discrepancies in relation to annuli on otolith edges). There was a linear relationship between otolith weight and fish age and an exponential relationship between otolith weight and fish length. Both otolith length and otolith width reached an asymptote at about 15 years, when fish length also approached its maximum. However, otolith thickness continued to increase throughout the life of the fish and, after about 15 years, contributed most to the increase in otolith weight. This confirmed that otoliths continued to grow in thickness and that annuli were laid down throughout life, and that cod could be aged reliably to the maximum age. The annulus pattern is very clear and distinct, and the reading techniques are fully described, including recognition of 'larval' and 'false' rings. Various differences were found in the growth rates, and the length-weight relationships for males and females, for cod caught in 1986-91 and those caught in 1949-51, and various subpopulations are discussed. The von Bertalanffy growth parameters (all individuals combined) were estimated at L∞ = 1202 mm, k=0.108 and t0= -0.832. The availability of a reliable ageing method provides the first opportunity to determine year of birth and thus to examine the age structure of populations and to effectively manage cod populations that have declined in abundance.
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Pratt, Brian R. "Desiccation cracks provide evidence of lake drying on Mars, Sutton Island member, Murray formation, Gale Crater: COMMENT." Geology 46, no. 8 (August 1, 2018): e449-e449. http://dx.doi.org/10.1130/g45084c.1.
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Stein, N., J. P. Grotzinger, J. Schieber, N. Mangold, B. Hallet, D. Y. Sumner, and C. Fedo. "Desiccation cracks provide evidence of lake drying on Mars, Sutton Island member, Murray formation, Gale crater: REPLY." Geology 46, no. 8 (August 1, 2018): e450-e450. http://dx.doi.org/10.1130/g45237y.1.
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McLaren, S., M. W. Wallace, B. J. Pillans, S. J. Gallagher, J. A. Miranda, and M. T. Warne. "Revised stratigraphy of the Blanchetown Clay, Murray Basin: age constraints on the evolution of paleo Lake Bungunnia." Australian Journal of Earth Sciences 56, no. 2 (March 2009): 259–70. http://dx.doi.org/10.1080/08120090802547074.
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Currey, N. A., W. I. Benko, B. T. Yaru, and R. Kabi. "Determination of heavy metals, arsenic and selenium in Barramundi (Lates calcarifer) from Lake Murray, Papua New Guinea." Science of The Total Environment 125 (September 1992): 305–20. http://dx.doi.org/10.1016/0048-9697(92)90398-c.
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Fluin, Jennie, John Tibby, and Peter Gell. "The palaeolimnological record from lake Cullulleraine, lower Murray River (south-east Australia): implications for understanding riverine histories." Journal of Paleolimnology 43, no. 2 (April 10, 2009): 309–22. http://dx.doi.org/10.1007/s10933-009-9333-8.
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Webster, Ian T., Holger Maier, Michael Burch, and Peter Baker. "Influence of wind on water levels and lagoonriver exchange in the River Murray, Australia." Marine and Freshwater Research 48, no. 6 (1997): 541. http://dx.doi.org/10.1071/mf97027.
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This paper examines river water levels and water exchange between the river and an adjacent lagoon at a site on the River Murray about 150 km from its discharge point into Lake Alexandrina. Riverine water levels at the site underwent significant fluctuations (~ 0·3 m) which appeared to be mainly associated with fluctuations in the N–S component of wind rather than with discharge. The lagoon studied was connected by a channel to the river. The measured flow through the channel was almost always out and had an average rate over the 30 days of the study which was large enough to empty the lagoon in 9 days. It is hypothesized that the replenishment flow to the lagoon occurred as a seeping flow through the bank separating the lagoon from the river. Successful comparisons between measurements and computer simulations of river water level and of the flow through the channel confirmed that it was the wind stress acting on the surface that mediated variations in riverine water levels and the exchange between river and lagoon.
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Chessman, BC. "Seasonal and Diel Activity of Fresh-Water Turtles in the Murray Valley, Victoria and New South-Wales." Wildlife Research 15, no. 3 (1988): 267. http://dx.doi.org/10.1071/wr9880267.
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Activity cycles of Chelodina expansa, C. longicollis and Emydura macquarii were inferred from captures in baited traps set in the Murray River and Lake Boga. C. expansa and E, macquarii were caught only from October to April, while C. longicollis was taken in all months but June and July. Minimum water temperatures at capture were highest for C. expansa and lowest for C. longicollis. Diel cycles of catch rate were often weak, but tended to be bimodal for all species, with peaks near dawn and in the afternoon or evening. Unlike the Chelodina species, E. macquarii was ofen caught near midnight. In the laboratory (at c.24�C with light:dark 12:12 h), the average diel pattern of locomotor activity was weakly bimodal in C. expansa, strongly bimodal in C. longicollis and unimodal in E. macquarii.
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Stone, Ian R. "Valedictory." Polar Record 52, no. 6 (November 2016): 619–20. http://dx.doi.org/10.1017/s0032247416000504.
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Towards midnight on 27 June 1787, it was clear, serene and moonlit, Edward Gibbon, certainly the greatest historian of his own, and possibly of any other, era laid down his pen after having written the last lines of his masterpiece The history of the decline and fall of the Roman Empire. He did this in the agreeable surroundings of the summer house in his garden at Lausanne overlooking the lake. He commented that his first emotion was the recovery of his freedom after so many years of unremitting labour but soon ‘a sober melancholy was spread over my mind by the idea that I had taken my everlasting leave’ of the ‘old and agreeable companion’ that his book had become to him over the years (Murray 1896: 333–334).
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DeLuca, Erik. "Wolf Listeners: An Introduction to the Acoustemological Politics and Poetics of Isle Royale National Park." Leonardo Music Journal 26 (December 2016): 87–90. http://dx.doi.org/10.1162/lmj_a_00982.
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Listening to wolf howls as both material object and socially constructed metaphor highlights the contested relationship between nature and culture. The author conducted field research on Isle Royale National Park from 2011 to 2015, from which data he offers a narrative wherein citizen-scientists who listen for the howl literally “lend their ears” to a wolf biologist who has led the longest continuous predator-prey study in the world. The theoretical framework of this essay extends acoustic ecology, first theorized by R. Murray Schafer, to include environmental history and cultural theory, which problematizes definitions of “nature” and “natural.” Ultimately, this introduction describes a nuanced form of participatory, situational environmental music that plays out in the everyday lives of those listening on this remote, roadless island on Lake Superior.
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Kattel, Giri, Peter Gell, Atun Zawadzki, and Linda Barry. "Palaeoecological evidence for sustained change in a shallow Murray River (Australia) floodplain lake: regime shift or press response?" Hydrobiologia 787, no. 1 (September 2, 2016): 269–90. http://dx.doi.org/10.1007/s10750-016-2970-9.
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Cartwright, I., K. Hannam, and T. R. Weaver. "Constraining flow paths of saline groundwater at basin margins using hydrochemistry and environmental isotopes: Lake Cooper, Murray Basin, Australia." Australian Journal of Earth Sciences 54, no. 8 (December 2007): 1103–22. http://dx.doi.org/10.1080/08120090701615741.
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