Diet of the Australian bass, Macquaria novemaculeata (Perciformes : Percichthyidae), in the Sydney Basin

1985 ◽  
Vol 36 (2) ◽  
pp. 219 ◽  
Author(s):  
JH Harris
Keyword(s):  
New South ◽  
Habitat Type ◽  
River Estuary ◽  
Stomach Contents ◽  
Food Type ◽  
Stomach Fullness ◽  
Important Food ◽  
South Wales ◽  
Terrestrial Animal ◽  
Lotic Habitats

Stomach contents of Australian bass, M. novemaculeata, sampled from the Hawkesbury River and Georges River in the Sydney Basin, New South Wales, between November 1977 and January 1982 were analysed by the occurrence and points methods. Stomach fullness was also recorded. A total of 143 aquatic and terrestrial animal taxa were present in the diet, and these were grouped into 19 food types for analysis. M. novemaculeata is a euryphagic carnivore. Season and habitat type had significant effects on composition of the diet. Insects were the most important food type, followed by fish and large crustaceans. A large proportion of the diet of bass was derived from allochthonous sources, mainly during summer, and especially in lotic habitats. Mean stomach fullness was highest in spring and lowest in winter. Young M. novernaculeata (TL 11-47 mm) from the Hawkesbury River estuary fed on far fewer prey taxa (mainly chironomids and copepods) than did adults. Dietary overlap occurs between M. novemaculeata and many other carnivorous freshwater vertebrates in the Sydney Basin. However, persistent competitive clashes are generally avoided, either by differences in microhabitat preference and feeding behaviour or by larger-scale habitat partitioning.

Food of the Snake-Necked Turtle, Chelodina Longicollis (Shaw) (Testudines: Chelidae) in the Murray Valley, Victoria and New South Wales.

1984 ◽  
Vol 11 (3) ◽  
pp. 573 ◽  
Author(s):  
BC Chessman
Keyword(s):  
Benthic Invertebrates ◽  
New South ◽  
Stomach Contents ◽  
Decapod Crustaceans ◽  
Important Food ◽  
Terrestrial Invertebrates ◽  
South Wales ◽  
Murray River ◽  
Planktonic Crustaceans ◽  
Chelodina Longicollis

The diet of C. longicollis was inferred from analysis ofthe stomach contents of 105 turtles collected from the Murray River and associated water bodies in south-eastem Australia. The most important food items in terms of volume were carrion and decapod crustaceans in the river, camon and littoral-benthic invertebrates in lakes and ponds containing fish, and planktonic crustaceans (mostly Cladocera) in ponds and pools without fish. Terrestrial invertebrates, which had presumably fallen into the water, nektonic insects and whole fish were also eaten. Diet varied relatively little with turtle size and sex, although juveniles ate relatively less carrion and more littoral and benthic invertebrates than adults. Within the constraints of its obligate carnivory, C. longicollis is a catholic and opportunistic feeder.

When, where and why do people encounter Australian brownsnakes (Pseudonaja textilis : Elapidae)?

1999 ◽  
Vol 26 (5) ◽  
pp. 675 ◽  
Author(s):  
P. B. Whitaker ◽  
R. Shine
Keyword(s):  
Air Temperature ◽  
Agricultural Land ◽  
New South ◽  
Habitat Type ◽  
Weather Conditions ◽  
Time Of Day ◽  
South Wales ◽  
Experienced Observer ◽  
Close Proximity ◽  
Species Ecology

Encounters between humans and dangerously venomous snakes put both participants at serious risk, so the determinants of such encounters warrant attention. Pseudonaja textilis is a large fast-moving elapid snake responsible for most snakebite fatalities in Australia. As part of a broad ecological study of this species in agricultural land near Leeton, New South Wales, we set out to identify factors influencing the probability that a human walking in farmland would come into close proximity to a brownsnake. Over a three-year period, we walked regular transects to quantify the number and rate of snake encounters, and the proportion of snakes above ground that could be seen. The rate of encounters depended upon a series of factors, including season, time of day, habitat type, weather conditions (wind and air temperature) and shade (light v. dark) of the observers’ clothing. Interactions between factors were also important: for example, the effect of air temperature on encounter probability differed with season and snake gender, and the effect of the observers’ shade of clothing differed with cloud cover. Remarkably, even a highly-experienced observer actually saw <25% of the telemetrically monitored snakes that were known to be active (i.e. above ground) nearby. This result reflects the snakes’ ability to evade people and to escape detection, even in the flat and sparsely vegetated study area. The proportion of snakes that were visible was influenced by the same kinds of factors as described above. Most of the factors biasing encounter rates are readily interpretable from information on other facets of the species’ ecology, and knowledge of these factors may facilitate safer coexistence between snakes and people.

Seasonal Changes in Diet Preferences of Free-Ranging Red Kangaroos, Euros and Sheep in Western New South Wales.

1977 ◽  
Vol 4 (2) ◽  
pp. 127 ◽  
Author(s):  
BA Ellis ◽  
EM Russell ◽  
TJ Dawson ◽  
CJF Harrop
Keyword(s):  
Animal Species ◽  
New South ◽  
New South Wales ◽  
Stomach Contents ◽  
Ovis Aries ◽  
Severe Drought ◽  
Red Kangaroo ◽  
South Wales ◽  
Selective Eating ◽  
Free Ranging

Stomach contents of free-ranging animals were analysed botanically for low Atriplex shrubland in western New South Wales, Australia, during 1972-74 in good seasons producing abundant growth and diversity of vegetation. Red kangaroo (Megaleia rufa), euro (Macropus robustus) and sheep (Ovis aries) selected grass and forbs when those were readily available. In poorer pasture sheep selected mainly flat-leaved chenopods (saltbush) and kangaroos selected mainly grass with different amounts of flat- or round-leaved chenopods. Euros were the most selective, eating grass even when there was little grass present. Potential overlaps in diet between kangaroos and sheep were greatest in good pasture and least in the poorest conditions. The other groups of plants considered were non-chenopod shrubs and browse. Extent of overlap was not clear, because animals may have eaten different species within the groups of plants. The study period did not include any severe drought, in which overlap in diet and competition between animal species would have been most significant.

Above- and below-ground biomasses of two species of mangrove on the Hawkesbury River estuary, New South Wales

1997 ◽  
Vol 48 (2) ◽  
pp. 147 ◽  
Author(s):  
Neil Saintilan
Keyword(s):  
New South ◽  
New South Wales ◽  
River Estuary ◽  
Avicennia Marina ◽  
Above Ground Biomass ◽  
Aegiceras Corniculatum ◽  
South Wales ◽  
Below Ground ◽  
Mangrove Communities ◽  
Intertidal Environments

Above- and below-ground biomasses of two species of mangrove, Avicennia marina and Aegiceras corniculatum, were estimated in a range of intertidal environments along the Hawkesbury River. Estimates of biomass of Avicennia communities in freshly accreted brackish substrata were in the order of 40 kg m–2, the highest figure ever recorded for temperate mangrove communities. The above-ground biomass communities of each species declined with increasing substratum salinity, whereas root/shoot ratios increased with increasing substratum salinity.

Generation and decay of hydrogen peroxide in estuarine waters

1988 ◽  
Vol 39 (3) ◽  
pp. 289 ◽  
Author(s):  
R Szymczak ◽  
TD Waite
Keyword(s):  
Hydrogen Peroxide ◽  
New South ◽  
River Estuary ◽  
Early Morning ◽  
Molar Absorptivity ◽  
Laboratory Studies ◽  
South Wales ◽  
Production Of Hydrogen ◽  
Bottom Waters ◽  
Rate Of Decay

Apart from its central role in photosynthesis, one of the most dramatic effects of light in marine and freshwater systems is its ability to generate reactive chemical intermediates. Of these, hydrogen peroxide is one of the more stable and easily detected. Aspects of the generation and decay of hydrogen peroxide in the Port Hacking River estuary, New South Wales, have been investigated in a number of field and laboratory studies. Peroxide concentrations in surface waters in the early morning are relatively uniform over the estuary and typically less than 35 nM, whereas concentrations in mid-afternoon in excess of 100 nM have been observed. Variation of peroxide concentration with depth in the deep basins of Port Hacking is dependent on the extent of structure within the water column, with little mixing of surface- generated peroxide into poorly-illuminated bottom waters under stratified conditions. Laboratory studies confirmed that light induces the production of hydrogen peroxide, the initial rate of production increasing with increasing molar absorptivity of the filtered water sample. Filtration of samples had little effect on the generation of hydrogen peroxide but dramatically reduced the rate of decay of photogenerated hydrogen peroxide.

How past sea-level changes can inform future planning: A case study from the Macleay River estuary, New South Wales, Australia

The Holocene ◽  
2014 ◽  
Vol 24 (11) ◽  
pp. 1591-1601 ◽  
Author(s):  
Sarah A McGowan ◽  
Robert GV Baker
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
New South ◽  
New South Wales ◽  
River Estuary ◽  
The Past ◽  
Case Study Area ◽  
South Wales ◽  
The Future

Climate change poses many challenges for the future management and development of the coastal zone. Uncertainties in the rate of future sea-level rise reduce our ability to project potential future impacts. This study seeks to further develop the past–present–future methodology proposed in Baker and McGowan and apply it to an additional case study, the Macleay River estuary, New South Wales (NSW), Australia. The past–present–future methodology uses evidence from the past, the Holocene and Pleistocene, to formulate a response function that can be used to project future sea-level heights. Three scenarios for 2100 were developed to emphasise the uncertainties surrounding future sea levels and the need to consider multiple sea-level rise scenarios when planning for the future: a best case (90 cm rise), mid-case (2.6 m rise) and worst case (5 m rise). Light detection and ranging (LiDAR) data were used to project each of the three scenarios onto the case study area of South West Rocks. The methodology was tested by using shell samples extracted from cores which were AMS dated to determine whether or not Holocene estuarine conditions correlated with the proposed future sea-level rise inundation scenarios. We also conducted an audit of potentially affected infrastructure and land uses, and proposed possible future adaptation strategies for the case study area.

scholarly journals Natural diet and feeding habits of a freshwater prawn (Macrobrachium carcinus: Crustacea, Decapoda) in the estuary of the Amazon River

2014 ◽  
Vol 44 (2) ◽  
pp. 235-244 ◽  
Author(s):  
Jô de Farias Lima ◽  
Jamile da Silva Garcia ◽  
Thibério Carvalho da Silva
Keyword(s):  
Feeding Habits ◽  
River Estuary ◽  
Stomach Contents ◽  
Freshwater Prawn ◽  
Amazon River ◽  
Feeding Preferences ◽  
Important Food ◽  
Natural Diet ◽  
Food Items ◽  
Stomach Analysis

Macrobrachium carcinus is a Brazilian native prawn with recognized potential for use in aquaculture activities. However, there is little information about the natural diet and feeding habits of this species. The aim of this study was the identification of the diet items of M. carcinus based on the analysis of the stomach contents. Specimens were collected in the Amazon River estuary between January 2009 and January 2010. The stomach analysis was carried out by using the frequency of occurrence (FO), methods of points (MP) and feeding index (FI). It was observed that prawns fed on detritus, animals and plant fragments as the most important food items. Sediment accounted for the main stomach content, accounting for 43.2% by the MP, 44.9% by FI and 100% by the FO. Sexual differences in feeding preferences were not found in this study, and seasonal differences in the frequency of items ingested by M. carcinus were not observed. The results indicated that M. carcinus can be considered omnivorous species, but with an important carnivorous component, similar to that found in other Macrobrachium species.

Diet of the Murray Turtle, Emydura-Macquarii (Gray) (Testudines, Chelidae)

1986 ◽  
Vol 13 (1) ◽  
pp. 65 ◽  
Author(s):  
BC Chessman
Keyword(s):  
Aquatic Macrophytes ◽  
Aquatic Invertebrates ◽  
New South ◽  
Stomach Contents ◽  
Filamentous Algae ◽  
Terrestrial Invertebrates ◽  
Dietary Shift ◽  
South Wales ◽  
Murray River ◽  
Males And Females

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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