scholarly journals Virally-Mediated Versus Grazer-Induced Mortality Rates in a Warm-Temperate Inverse Estuary (Spencer Gulf, South Australia)

2014 ◽  
Vol 04 (04) ◽  
pp. 257-278
Author(s):  
Laurent Seuront ◽  
Mark Doubell ◽  
Paul Van Ruth
Keyword(s):  
South Australia ◽  
Mortality Rates ◽  
Inverse Estuary ◽  
Warm Temperate

Effect of selenium supplementation on survival, liveweight and wool weight of young sheep on Kangaroo Island, South Australia

1979 ◽  
Vol 19 (101) ◽  
pp. 689 ◽  
Author(s):  
SK Walker ◽  
GP Hall ◽  
DH Smith ◽  
RW Ponzoni ◽  
GJ Judson
Keyword(s):  
Total Dose ◽  
Whole Blood ◽  
Sodium Selenite ◽  
South Australia ◽  
Selenium Concentration ◽  
Mortality Rates ◽  
Selenium Supplementation ◽  
First Year ◽  
Weaning Weight ◽  
Fleece Weight

The responses in liveweight, wool weight and survival, to selenium supplementation, were studied in young sheep from weaning to yearling age. The experiment was conducted over three years. In the first year, one sodium selenite supplementation rate was used (total dose 46.5 mg). During the following two years two supplementation rates were administered (total doses 46.5 mg and 93 mg). Mean concentrations of selenium in whole blood in unsupplemented sheep varied from 0.19-0.56 pmol l-l and from 0.20-0.44 pmol l-1 in the two years in which concentrations were measured. Supplementation, which commenced at lamb marking, increased the selenium concentration in sheep at weaning and thereafter. Selenium supplementation improved the break-of-season weight (P < 0.01) and yearling weight (P < 0.01 ) but not weaning weight (0.05 < P < 0.1 ). Hogget fleece weight was improved (P < 0.01 ) and mortality reduced (P < 0.01) by selenium supplementation. There was a treatment x year interaction in mortality rates (P < 0.01 ). There were no significant differences between the two supplementation rates

A General Account of the Intertidal Ecology of South Australian Coasts

1958 ◽  
Vol 9 (2) ◽  
pp. 217 ◽  
Author(s):  
HBS Womersly ◽  
SJ Edmonds
Keyword(s):  
Western Australia ◽  
Littoral Zone ◽  
South Australia ◽  
Transitional Region ◽  
The South ◽  
South Wales ◽  
Marine Angiosperms ◽  
Rocky Coast ◽  
Warm Temperate ◽  
Western Australian

An account is given of the environmental features. the intertidal ecology. and the biogeographical relationships of the coast of the State of South Australia . The central and western coasts of South Australia are similar ecologically in comparable areas . In the supralittoral Melaraphe unifasciata (Gray) is dominant (except where conditions are very calm) and at high levels on very exposed coasts Calothrix fasciculata C. Agardh is found. The littoral zone where the coast is most exposed consists of barnacles-Chamaesipho in the upper littoral, Catophragmus in the mid littoral, and Balanus in the lower littoral-but where the coast is more sheltered it consists of molluscs in the upper and mid littoral and algae (Corallina, Gelidium, or Hormosira) in the lower littoral. In the upper sublittoral fucoid algae or in calm regions marine angiosperms are dominant. The south-east coast, however, differs in some respects from the central and west coasts. The number of barnacles found in the littoral zone is much reduced and the giant brown algae, Durvillea potatorum Areschoug and Macrocystis angustifolia Bory, are dominant in the upper sublittoral. This is associated with slightly lower sea temperatures. Sheltered coasts are more prominent in South Australia than in the eastern States of Australia. These include the shores of Spencer and St. Vincent Gulfs, the northern shores of Kangaroo I., and a number of scattered bays. The similarities between the coasts of South Australia and Victoria (Bennett and Pope 1953) are greater than the differences. Consequently the proposal of Bennett and Pope to recognize the Victorian and Tasmanian coasts as the Maugean Biogeographical Provinoe and the South Australian and the south-west Western Australian coasts as the Flindersian Province appears to be unjustified. It is suggested that the Naugean is best regarded as a subprovince with the Flindersian. The latter includes most of the coast of southern Australia. Considerable differences are noticeable between the organisms which inhabit the rocky coast of South Australia and the south coast of Western Australia. The available evidence indicates that a transition from the Flindersian to the tropical Dampierian Province occurs along the south and west coasts of Western Australia. The terms "Indo-Australian Province" and "Baudinian Province" have been proposed by previous authors to describe this transitional region. The Flindersian Province appears to be intermediate between cold-temperate and warm-temperate regions, becoming distinctly cool-temperate in Tasmania. It is relatively distinct from the warm-temperate Peronian Province of the coast of New South Wales.

Littoral ecology and biogeography of the southern oceans

1960 ◽  
Vol 152 (949) ◽  
pp. 577-624 ◽  
Keyword(s):  
New Zealand ◽  
Lower Limit ◽  
Personal Experience ◽  
New South ◽  
Algal Growth ◽  
South Australia ◽  
The West ◽  
South Wales ◽  
Warm Temperate ◽  
Southern Oceans

This contribution is concerned with the littoral ecology and biogeography of the southern oceans, and at the outset I would like to define its scope. I have used the term littoral in a broad sense, to include all those zones (supralittoral, intertidal or true littoral, and sub-littoral) between the lower limit of the land vegetation and the lower limit of algal growth. Attention will be concentrated on the southern cold-temperate zone, which is also broadly defined in view of the varying limits which have been placed on it according to the bases used; oceanographic, faunistic or floristic. Adjoining antarctic and warm temperate zones are discussed where relevant. The following account is based on personal experience of the greater part of the New Zealand coastline, the Chatham Islands and the west coast of South America from Montemar near Valparaiso to Isla Hermite in the Cape Horn group. All these regions have been studied intensively. Brief visits have also been paid to shores in Peru, in New South Wales near Sydney, and in South Australia.

Performance of Hereford and Friesian × Hereford dams and their Hereford- and Friesian-sired progeny in a Mediterranean environment

1981 ◽  
Vol 21 (109) ◽  
pp. 137 ◽  
Author(s):  
DR Gifford ◽  
PC Stephens ◽  
RJ Lampe ◽  
RW Ponzoni ◽  
HR Day
Keyword(s):  
Birth Weight ◽  
Mortality Rate ◽  
South Australia ◽  
Mortality Rates ◽  
Mediterranean Environment ◽  
Beef Industry ◽  
Slaughter Age ◽  
Maternal Performance ◽  
Calving Difficulty ◽  
Practical Implications

The reproductive and maternal performance of Hereford and Friesian x Hereford dams and the growth and carcase characteristics of their Hereford- and Friesian-sired calves in the Mediterranean environment of South Australia are reported. The two dam breeds did not differ in fertility and their calves had similar mortality rates. Even though calves from Hereford dams were lighter at birth than those from crossbred dams (30.8 vs 33.0 kg), Hereford dams required more assistance at calving (16% vs 8%). There were no differences in birth weight and incidence of calving difficulty of Hereford- and Friesian-sired progeny, but Friesian-sired progeny had a higher mortality rate (11% vs 5%). Calves from crossbred dams were heavier at weaning than those from Hereford dams (274 vs 235 kg) but Hereford- and Friesian-sired progeny were the same weight at weaning. Friesian-sired steers were heavier than Hereford-sired steers at 19- 21 months of age (478 vs 448 kg). The carcase characteristics of progeny of the two dam breeds did not differ significantly at either slaughter age. There were no significant differences in carcase characteristics of Hereford- and Friesian sired progeny slaughtered at 8- 10 months of age. When progeny were slaughtered at 19- 21 months of age, carcases of Friesian-sired steers were heavier (238 vs 222 kg) and leaner (0.49 vs 0.86 mm) than those of Hereford-sired steers. The practical implications of the use of Hereford and Friesian breeds in the southern Australian beef industry are discussed.

scholarly journals A stage-based estimator of daily egg production

2018 ◽  
Vol 75 (5) ◽  
pp. 1638-1646
Author(s):  
Richard McGarvey ◽  
Mike A Steer ◽  
Janet M Matthews ◽  
Tim M Ward
Keyword(s):  
Mortality Rate ◽  
Egg Production ◽  
South Australia ◽  
Mortality Rates ◽  
Egg Mortality ◽  
Age Cohorts ◽  
Wide Range ◽  
Egg Density ◽  
Simulation Testing ◽  
Daily Spawning

Abstract Snapper (Chrysophrys auratus) in South Australia spawn over a wide range of daily times and hatch in ∼1.5 d. Traditional estimates of daily egg production (i) divide sampled eggs into daily age cohorts, e.g. days 1 and 2, (ii) compute cohort ages by assuming that all spawning occurs at a fixed daily peak hour, and (iii) link the estimation of spawning egg density with egg mortality rate by regressing cohort egg densities against cohort age. We propose a method for estimating daily egg production, the number of eggs spawned per unit area per day (P0), without these assumptions. We use a range of estimates of snapper egg mortality rate obtained from prior studies to backcorrect for egg mortality to the age 0 spawning egg density for each stage of eggs individually rather than aggregating into daily cohorts. P0 is estimated as a mean of sample tow densities rather than as a regression intercept. This stage-based P0 estimator avoids errors associated with assuming a fixed daily spawning hour and classifying eggs into day 1 or 2. It requires no regressions of sampled daily cohort egg densities against age, which often provide imprecise estimates of mortality rates. Simulation testing showed 1–2% accuracy for this estimator of P0. The uncertainty of assuming egg mortality rates is moderated by the insensitivity of estimates of P0 to the input value of egg mortality rate.

scholarly journals Interactions between a Top Order Predator and Exotic Mesopredators in the Australian Rangelands

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Katherine E. Moseby ◽  
Heather Neilly ◽  
John L. Read ◽  
Helen A. Crisp
Keyword(s):  
Intraguild Predation ◽  
Prey Species ◽  
Red Fox ◽  
Interference Competition ◽  
South Australia ◽  
Mortality Rates ◽  
Net Benefit ◽  
Male And Female ◽  
Dominant Mechanism ◽  
Feral Cats

An increase in mesopredators caused by the removal of top-order predators can have significant implications for threatened wildlife. Recent evidence suggests that Australia’s top-order predator, the dingo, may suppress the introduced cat and red fox. We tested this relationship by reintroducing 7 foxes and 6 feral cats into a 37 km2fenced paddock in arid South Australia inhabited by a male and female dingo. GPS datalogger collars recorded locations of all experimental animals every 2 hours. Interactions between species, mortality rates, and postmortems were used to determine the mechanisms of any suppression. Dingoes killed all 7 foxes within 17 days of their introduction and no pre-death interactions were recorded. All 6 feral cats died between 20 and 103 days after release and dingoes were implicated in the deaths of at least 3 cats. Dingoes typically stayed with fox and cat carcasses for several hours after death and/or returned several times in ensuing days. There was no evidence of intraguild predation, interference competition was the dominant mechanism of suppression. Our results support anecdotal evidence that dingoes may suppress exotic mesopredators, particularly foxes. We outline further research required to determine if this suppression translates into a net benefit for threatened prey species.

The Influence of Drought on the Survival of Eggs of Austroicetes cruciata, Sauss. (Orthoptera) in South Australia

1945 ◽  
Vol 35 (3) ◽  
pp. 243-250 ◽  
Author(s):  
L. C. Birch ◽  
H. G. Andrewartha
Keyword(s):  
Mortality Rate ◽  
High Mortality ◽  
South Australia ◽  
Mortality Rates

Drought is the only factor in the environment of the eggs of Austroicetes cruciata that is likely to cause a high mortality rate of the eggs in the field.The eggs may be exposed to drought at various stages of their development. The probability of high mortality due to exposure to drought during the winter is considered to be negligible.The probability of a high mortality rate due to drought when the nymphs are hatching is unimportant. From an analysis of the meteorological records for 50 years, it was estimated that high mortality rates from this cause may occur 12 times in a thousand years at Hawker and less frequently elsewhere in the grasshopper belt.The eggs are exposed to the most severe hazards during the summer. An analysis of the meteorological records shows that severe mortality rates may have occurred as a result of drought in the summer from one to seven times during the 50 years 1891–1940, depending upon the district.

Physical property distributions and seasonal trends in Spencer Gulf, South Australia: an inverse estuary

1986 ◽  
Vol 37 (1) ◽  
pp. 39 ◽  
Author(s):  
RA Nunes ◽  
GW Lennon
Keyword(s):  
Time Series ◽  
Seasonal Variations ◽  
Large Scale ◽  
South Australia ◽  
Physical Property ◽  
Late Summer ◽  
Fluid Loss ◽  
Inverse Estuary ◽  
Systematic Program

Results are described from the first long-term, systematic program of oceanographic measurements in Spencer Gulf, South Australia. The gulf belongs to a subset of semi-enclosed seas that are characterized by a net fluid loss, in this case induced by excess evaporation, and a resulting circulation that is the reverse of that found in a classical estuary. In Spencer Gulf, this inverse estuary character involves the production of salinities as high as 48 at the head in late summer. The seasonal variations of temperature and salinity, from both large-scale CTD surveys and time-series observations at a fixed station, reveal the manner in which the gulf responds to seasonal influences. From such information, the gulf's dispersive capabilities are quantitatively assessed, and the implications of thermohaline processes for gulf-ocean exchange are discussed.

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