Predation of Fish in Farm Dams by Cormorants, Phalacrocorax Spp.

1984 ◽  
Vol 11 (3) ◽  
pp. 559 ◽  
Author(s):  
CG Barlow ◽  
K Bock
Keyword(s):  
New South ◽  
New South Wales ◽  
Warm Water ◽  
Great Cormorant ◽  
Alternative Prey ◽  
Phalacrocorax Carbo ◽  
Cherax Destructor ◽  
South Wales ◽  
Black Cormorant ◽  
Stocking Rates

The effect of cormorants on the survival of native warm-water fishes in farm dams in south-western New South Wales was monitored during 1979 and 1980. Three species of cormorants frequented the dams: the great cormorant Phalacrocorax carbo, the little pied cormorant P. melanoleucos, and the little black cormorant P. sulcirostris. In dams fished by cormorants, more than 50% ofthe fish were consumed unless abundant alternative prey, in this case crayfish Cherax destructor, was present. Dams stocked with few fish (approximately 150 ha-1) were less commonly fished than those stocked with many fish (more than 450 ha-1). The majority of dams in the study area were fished by cormorants, which were present from midwinter to midsummer in both years. The results, and an examination of aspects of cormorant biology and methods used to prevent birds eating fish at hatcheries, indicated that buffer populations of crustaceans and low fish stocking rates are suitable methods for minimizing predation of fish in farm dams by cormorants.

The effects of grazing and season on the stability of Chloris Spp. (Windmill grasses) in natural pasture at Trangie, New South Wales.

1978 ◽  
Vol 1 (2) ◽  
pp. 106 ◽  
Author(s):  
DL Michalk ◽  
PK Herbert
Keyword(s):  
New South ◽  
New South Wales ◽  
Grazing Pressure ◽  
Basal Diameter ◽  
South Wales ◽  
Natural Pasture ◽  
Mean Diameter ◽  
The Mean ◽  
The Stability ◽  
Stocking Rates

A study of the density and basal diameter of Chloris acicularis Lindl. (syn. Enteropogon acicularis (LindlJLazar. - curly windmill grass) and C. truncata R. Br. (windmill grass) was made at two stocking rates over a period of eight years. The propor- tion of ground covered by these Chloris species varied widely with season, and to a lesser extent with grazing pressure. The density of both species increased in good seasons, while the mean diameter decreased because of the number of new seedlings. Although C. truncata seedlings were more numerous in good seasons, they did not survive as well as did C. acicularis seedlings during prolonged dry periods.

Palatability to sheep of the Eragrostis curvula complex. 3. A comparison of naturalised and selected taxa

1988 ◽  
Vol 28 (1) ◽  
pp. 53 ◽  
Author(s):  
WH Johnston
Keyword(s):  
New South ◽  
New South Wales ◽  
Wagga Wagga ◽  
Eragrostis Curvula ◽  
South Wales ◽  
Stocking Rates ◽  
Relative Palatability

The palatability of 20 accessions of E. curvula collected from naturalised populations in New South Wales was compared on 7 occasions with 2 selected accessions previously found to be highly palatable. The experiment was conducted at Wagga Wagga, N.S.W., between January 198 1 and July 1983. The relative palatability of most accessions was substantially similar from rating to rating, despite differences in the extent to which the trial was grazed. Palatability was related to the agronomic group to which the accessions belonged. For the naturalised taxa, Curvula was ranked equal to Tall Chloromelas. but both were more palatable than Short Chloromelas. The naturalised accessions were all less palatable than the selected accessions. It was concluded that the selected accessions were sufficiently palatable to be well utilised in pastures by stock grazing at commercial stocking rates.

The influence of grazing by cattle and sheep on the population dynamics of Bladder Saltbush (Atriplex Vesicaria) and white top (Danthonia caespitosa).

1980 ◽  
Vol 2 (2) ◽  
pp. 208 ◽  
Author(s):  
RD Graetz
Keyword(s):  
Population Dynamics ◽  
New South ◽  
New South Wales ◽  
Population Data ◽  
Plant Population ◽  
Rainfall Pattern ◽  
South Wales ◽  
A Site ◽  
Stocking Rates ◽  
Cattle And Sheep

Plant population data for the pass white-top (Danthonia caespitosa) and for bladder saltbush (Atriplex vesicaria) were collected for four years from a pasture continuously grazed by either cattle or sheep (at equivalent stocking rates) at a site near Booligal, New South Wales. During the four years of the experiment the cattle and sheep had different Impacts on the grass and scrub components of the pasture Sheep tended to deplete the numbers of pass plants far more than did cattle, whereas saltbush shrub numbers here little affected by either type of stock. The rainfall pattern experienced throughout the experiment had a far greater influence on the survival of both grass and shrub than did grazing.

SGS Nutrient Theme: environmental assessment of nutrient application to extensive pastures in the high rainfall zone of southern Australia

2003 ◽  
Vol 43 (8) ◽  
pp. 927 ◽  
Author(s):  
M. R. McCaskill ◽  
A. M. Ridley ◽  
A. Okom ◽  
R. E. White ◽  
M. H. Andrew ◽  
...  
Keyword(s):  
Nitrate Leaching ◽  
Surface Runoff ◽  
New South ◽  
Stream Water ◽  
New South Wales ◽  
Surface Flow ◽  
Stream Water Quality ◽  
Soil P ◽  
South Wales ◽  
Stocking Rates

To assess the risks and benefits of more intensive pasture management, 2 or 3 treatments with contrasting fertiliser regimes were selected from each site of the Sustainable Grazing Systems national experiment. The assessment used soil coring data, modelling and runoff nutrient concentration data.Soil acidification rates were estimated from the simulated nitrate leaching and product removal estimated from the stocking rates at each site. Much higher acidification rates were estimated at sites in Victoria and southern Western Australia than in northern New South Wales. This was because of a lower level of nitrate leaching in summer-dominant rainfall environments coupled with lower stocking rates. Simulations showed highest nitrate leaching on annual pastures, but that a phalaris pasture could reduce this, and a kikuyu pasture could almost fully control leaching.The concentration of P in surface runoff was related to soil P status at the 4 southern sites, indicating that greater use of P fertiliser would increase P movement into waterways. There was no relationship between soil P status and P in surface runoff at the northern New South Wales sites, and across all sites there were no relationships between P fertility and runoff N levels. Concentrations of P and N in runoff greatly exceeded stream water quality guidelines, even on treatments where only minimal P had been applied as fertiliser. There was also evidence of high spatial variation in surface runoff generation, with surface runoff from some plots less than 5% of the streamflow in nearby reference streams. There is therefore scope to control P concentrations in streams by retiring from production the parts of the landscape that generate high quantities of surface flow, but to intensify production on areas that produce little runoff.

Evaluation of natural annual pastures at Trangie in central western New South Wales. 1. Sheep production

1973 ◽  
Vol 13 (62) ◽  
pp. 238
Author(s):  
RJ Campbell ◽  
DG Saville ◽  
GE Robards
Keyword(s):  
New South ◽  
Management Strategies ◽  
New South Wales ◽  
Grazing Pressure ◽  
Stocking Rate ◽  
Wool Production ◽  
South Wales ◽  
Sheep Production ◽  
Stocking Rates ◽  
Sheep Wool

Natural annual pasture at Trangie, New South Wales, was set stocked from August, 1967 to December 1970 at rates of 2.5, 3.7, and 4.9 merino wethers per ha to determine an optimum stocking rate for the pasture type. All stocking rates were supported without the necessity to hand feed any sheep. Wool production per head was reduced significantly by increased stocking rate in 1968, but not in 1969 and 1970. The suppression of barley grass at the higher stocking rates appeared to benefit animal production in 1969. Substitution of portion of the natural annual pasture with areas of lucerne or natural perennial pasture was also investigated and found to be ineffective in increasing wool production per head above that of wethers at similar rates of stocking on natural annual pasture alone. Possible reasons for the apparent failure of the grazing supplements, particularly lucerne, are discussed in terms of grazing pressure and management strategies.

Waterbird Dynamics in the RIchmond VAlley, New SOuth Wales, 1974-77

1983 ◽  
Vol 10 (2) ◽  
pp. 319 ◽  
Author(s):  
DG Gosper ◽  
SV Briggs ◽  
SM Carpenter
Keyword(s):  
New South ◽  
New South Wales ◽  
Late Summer ◽  
Seasonal Abundance ◽  
Black Swan ◽  
Abundance Patterns ◽  
South Wales ◽  
Black Duck ◽  
Murray River ◽  
Black Cormorant

'Monthly waterbird counts from February 1974 to June 1977 at six wetlands in the Richmond River valley in northern coastal New South Wales were analysed to investigate relationships between numbers of each species, and season and water variables. Black swan, Pacific black duck, purple swamphen, dusky moorhen, cattle egret, comb-crested jacana and sharp-tailed sandpiper were strongly influenced by season. Grey teal, straw-necked ibis, little black cormorant, Pacific heron and black-winged stilt numbers were related to Murray River discharge, an index of inland wetland availability in New South Wales, northern Victoria and parts of southern Queensland. Numbers of most waterbirds were highest on the coast from late summer to the end of winter. Their seasonal abundance patterns conform with the results of some previous studies but differ somewhat from others.

Breeding Behaviour and Ecology of the Australian Pelican, Pelecanus Conspicillatus, in New South Wales.

1977 ◽  
Vol 4 (1) ◽  
pp. 37 ◽  
Author(s):  
WJM Vestjens
Keyword(s):  
New South ◽  
New South Wales ◽  
Perca Fluviatilis ◽  
Freshwater Crayfish ◽  
Goldfish Carassius Auratus ◽  
Cherax Destructor ◽  
South Wales ◽  
Perch Perca Fluviatilis ◽  
Competition For Food ◽  
A Minor

Australian pelicans (Pelecanus conspicillatus) were studied in colonies at 2 lakes in New South Wales. Adults regurgitated food for the young. Those up to 2 weeks old took liquid food from inside the tip of the adult's upper beak. Older ones took solid food from the adult's gullet, to age of about 3.5 months. After being fed, the young had convulsions lasting about 1 min; that did not happen after a second feeding immediately after the convulsion. Where there were 2 young of different sizes, only the larger convulsed, and sometimes the smaller was prevented from feeding and died of starvation. The survivor continued to have convulsions after feeding, as did single young, when there was no competition for food. Food was mainly fish; the most abundant fish was goldfish (Carassius auratus); a minor item was perch (Perca fluviatilis). Fish were 60 to 247 mm long and weighed 17 to 320 g. Crustaceans were less important and included freshwater crayfish (Cherax destructor) and shrimp (Macrobrachius sp.).

Evaluation of natural annual pasture at Trangie in central western New South Wales. 3. Effect of stocking rate on annual-dominated and perennial-dominated natural pastures

1978 ◽  
Vol 18 (92) ◽  
pp. 361 ◽  
Author(s):  
GE Robards ◽  
DL Michalk ◽  
RJ Pither
Keyword(s):  
New South ◽  
Perennial Grass ◽  
New South Wales ◽  
Perennial Grasses ◽  
Stocking Rate ◽  
Wool Production ◽  
South Wales ◽  
Natural Pasture ◽  
Ewe Lamb ◽  
Stocking Rates

A four year experiment is reported during which breeding Merino ewes grazed two natural pasture types at three stocking rates at Trangie in central-western New South Wales. Initially, the pasture on a red brown soil was dominated by cool season annual species, particularly Hordeum leporinum, Erodium species and Medicago species. The pasture on a heavier grey soil was dominated by the perennial grasses Chloris acicularis, C. truncata and Stipa variabilis. Clean wool production of ewes grazing the annual-dominated pasture was significantly (P< 0.05) higher than that of ewes grazing the perennial grass-dominated pasture even though the wool of the ewes grazing perennial pasture had a higher percentage clean yield (P < 0.05). The ewes on the annual-dominated pasture were significantly heavier in autumn and winter, and had a faster rate of wool growth in each season except spring, than ewes grazing perennial pasture. Number of lambs born per ewe, lamb birth weight and lamb growth rate were not affected by pasture type or stocking rate. Stocking rate had a small but statistically significant effect on clean wool production and only small effects on ewe liveweight, regardless of pasture type. When hand feeding of the pregnant ewes became necessary in the poor winters of 1971 and 1972 all stocking rates had to be commenced simultaneously. The significance of perennial grasses in these natural pastures is discussed in relationship to animal production, stocking rate, pasture and soil stability, and regeneration of grasses following favourable seasons.

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