The Inpact of River Discharge on Distribution and Production of the School Prawn Metapenaeus macleayi (Haswell) (Crustacea : Penaeidae) in the Clarence River Region, Northern New South Wales

1978 ◽  
Vol 29 (3) ◽  
pp. 311 ◽  
Author(s):  
JP Glaister
Keyword(s):  
River Discharge ◽  
Ecological Study ◽  
New South ◽  
Total Production ◽  
Catch Per Unit Effort ◽  
Lunar Periodicity ◽  
South Wales ◽  
River Region ◽  
Schooling Behaviour ◽  
The Difference

Relationships between river discharge and production (catch) of the school prawn M. macleayi were examined as part of an ecological study of this species in the Clarence River region. Schooling behaviour of juvenile M. macleayi exhibited a lunar periodicity and mean daily abundance peaked 5 days after full moon. This was followed 7 days later by a peak in mean daily abundance of emigrating juvenile M. macleayi. Fluctuations in the magnitude of the oceanic component of the total annual catch were found to determine the difference between high and low production seasons. During the period examined there was a direct relationship between Clarence River discharge and the oceanic component of total production of M. macleayi, for various time periods. The absence of a persistent trend in total annual production and annual catch per unit effort of M. macleayi in the Clarence River region suggests that the stock has not been overfished. Common peaks in mean monthly oceanic production of M. macleayi off the Clarence, Evans and Richmond Rivers suggest a common enhancement of the seasonal emigration of M. macleayi from the three estuaries in November due to increased river discharges. Successive troughs and peaks in mean monthly oceanic production suggest a northwards migration of M. macleayi from the Clarence and Evans Rivers and subsequent recruitment to the Evans and Richmond ocean fisheries respectively. Results indicate the importance of river discharge to production of M. macleayi and suggest that modification of discharges by restriction of freshwater flow could adversely effect production.

Use of products of straw decomposition by N2-fixing (C2H2-reducing) populations of bacteria in three soils from wheat-growing areas

1986 ◽  
Vol 37 (1) ◽  
pp. 1 ◽  
Author(s):  
MM Roper ◽  
DM Halsall
Keyword(s):  
Nitrogenase Activity ◽  
New South ◽  
Carbon Sources ◽  
Clay Content ◽  
Free Living ◽  
Straw Decomposition ◽  
South Wales ◽  
History Of ◽  
Straw Incorporation ◽  
The Difference

The potential for N2 fixation by free-living bacteria using straw as a source of energy was evaluated in three soils (one from Gunnedah and two from Cowra) representative of the wheat belt in New South Wales. All three soils had a history of straw incorporation. The abilities of the respective microbial populations to use a range of carbon sources, including potential products of decomposition of straw, was determined and compared with the size and composition of each population. Neutral to alkaline (pH 7.4) soil of high (51%) clay content from Gunnedah produced higher rates of nitrogenase activity with straw than more acid (pH 5.6) lower (17%) clay containing soil from Cowra (site B). Gunnedah soil also contained a larger population of N2-fixing bacteria which used a broader range of energy sources than soil from either Cowra site B or Cowra site W (pH 5.8, clay content 34%). There was little difference in the composition of the N2-fixing populations in each of the soils except that Azotobacter spp. were absent from the acid Cowra soils. It was concluded that the difference in behaviour of the respective N2-fixing populations was primarily due to the physical characteristics of the soil affecting the numbers and activities of diazotrophic microorganisms. In addition some soil environments failed to support specific organisms.

Movement and Growth of Tagged School Prawns, Metapenaeus macleayi (Haswell) (Crustacea : Penaeidae), in the Clarence River Region of Northern New South Wales

1978 ◽  
Vol 29 (5) ◽  
pp. 645 ◽  
Author(s):  
JP Glaister
Keyword(s):  
New South ◽  
New South Wales ◽  
Wound Site ◽  
South Wales ◽  
River Region

Movement and growth of M. macleayi in the Clarence River region were investigated during tagging studies using Atkins-type tags. Although some tagged prawns released into the estuary showed a marked susceptibility to developing lesions and skeletal necroses at the tag wound site, the majority were able to moult, bury and behave normally. Movement of tagged prawns suggested that M. macleayi from the Clarence River undertake limited northwards migrations which are possibly assisted by currents. Such movement may therefore contribute to the Evans Head fishery. Growth of tagged prawns appeared to be unusually rapid in the first 2 weeks after release but in subsequent weeks was found to be comparable with that recorded in other similar studies.

Nature Conservation in Rangelands: Lessons From Research on Reserve Selection in New South Wales.

1992 ◽  
Vol 14 (2) ◽  
pp. 214 ◽  
Author(s):  
RL Pressey
Keyword(s):  
Conservation Planning ◽  
New South ◽  
Full Range ◽  
New South Wales ◽  
Reserve Selection ◽  
South Wales ◽  
Land Systems ◽  
The Difference ◽  
Selection Of

Information on the features to be protected in a system of conservation reserves is an obvious requirement. The quality of the data base will primarily determine the effectiveness of conservation planning in protecting the full range of natural features in a region. However, the way in which data are used to make decisions on the locations of protected areas is also critical. Rigorous procedures for reserve selection can make the difference between achieving reservation goals or not. Research on reserve selection in New South Wales over recent years has concerned both data bases and procedures for guiding decisions. Reserve planning in many regions is based largely on some form of land classification like vegetation types or land systems. There are good reasons for using such land classes to guide the selection of reserves and to judge their representativeness. Nevertheless, they can have considerable limitations as a basis for protecting all the species in a region. These limitations are reviewed with references to more detailed discussions of particular issues. The paper also reviews a variety of procedures for selecting reserves which have been tested and applied in New South Wales. Some of the recent procedures are conceptually simple but very useful in identifying the requirements of reservation goals and demonstrating the options available to planners for representing particular features. Three principles are proposed which should underpin any attempt at systematic conservation planning.

Predation of Red Kangaroos, Macropus rufus, by the Dingo, Canis familiaris dingo (Blumenbach) in North-Western New South Wales

1981 ◽  
Vol 8 (2) ◽  
pp. 255 ◽  
Author(s):  
NC Shepherd
Keyword(s):  
New South ◽  
New South Wales ◽  
Pathological Finding ◽  
South Wales ◽  
Daily Rate ◽  
Rate Of Increase ◽  
Border Fence ◽  
Selection For ◽  
The Difference ◽  
North Western

Over 7 weeks a group of five dingoes killed 83 red kangaroos within 150 m of a watering point in north-western New South Wales. All except three of these kangaroos were juveniles. Detailed autopsies were performed on 17 of the dead kangaroos: primary predation was the only significant gross pathological finding; the dingoes had eaten portions from about half the kangaroos killed. The daily rate of killing was estimated to be about 0.38 kg prey per kg predator. The rate of killing and the selection for juvenile kangaroos suggested that dingoes could have a direct effect on kangaroo densities by limiting rate of increase. The significance of this finding is discussed with reference to the difference in abundance of kangaroos between the New South Wales and Queensland sides of the border fence.

Seasonal Field Energetics of the Rufous Rat-Kangaroo (Aepyprymnus-Rufescens)

1992 ◽  
Vol 40 (3) ◽  
pp. 279 ◽  
Author(s):  
IR Wallis ◽  
B Green
Keyword(s):  
New South ◽  
Water Flux ◽  
Behavioural Ecology ◽  
Free Living ◽  
Doubly Labelled Water ◽  
South Wales ◽  
Poor Understanding ◽  
Males And Females ◽  
The Mean ◽  
The Difference

Water flux and field metabolic rate (FMR) were measured by the doubly labelled water (DLW) method in free-living male and female rufous rat-kangaroos Aepyprymnus rufescens near Drake in northern New South Wales. The mean FMR of 499 kJ kg-1 day-1 was similar in winter and summer even though the difference in mean minimum temperatures between the two seasons was 20-degrees-C. Furthermore, we did not find any differences in FMR between males and females even though several females carried large pouch young or had young-at-foot. A poor understanding of the diet and the behavioural ecology of A. rufescens makes ft difficult to explain the similarities between sexes and seasons.

Effect of sod-seeding oats or barley, renovation, herbicide and broadcast nitrogen fertilizer on forage production of dryland lucerne

1976 ◽  
Vol 16 (79) ◽  
pp. 240
Author(s):  
RA Spurway ◽  
AC Gleeson
Keyword(s):  
Avena Sativa ◽  
New South ◽  
Basal Area ◽  
Early Summer ◽  
N Fertilizer ◽  
Total Production ◽  
Forage Production ◽  
South Wales ◽  
Cereal Species ◽  
Forage Yields

In four experiments at Tamworth, New South Wales in 1973 and 1974, forage production from dryland lucerne pastures (Medicago sativa cv. Hunter River) was evaluated following sod-seeding with oats (Avena sativa cv. Cooba and Coolabah) or barley (Hordeum vulgare cv. Beecher) in autumn, treatment with diquat and topdressing with 50 or 100 kg nitrogen (N) ha-1. Comparisons were also made with production from lucerne alone and with crops of oats and barley sown on conventional seedbeds. Total forage production from lucerne was approximately doubled (P < 0.05) in winter by sod-seeding with oats or barley. Differences between the cereal species were small and both responded significantly to N fertilizer. Herbicide did not significantly affect forage production. The sod-sown cereal reduced (P < 0.05) lucerne growth in winter, but in early summer when cereal growth had ceased neither the growth of lucerne nor its basal area differed significantly from that of unseeded lucerne pastures. In most experiments renovation or broadcasting N fertilizer gave small, but significant increases in lucerne production. Forage yields from conventionally sown oats and barley were 2 to 3 times larger (P < 0.05) than the total production of sod-sown plots. Per cent N in sod-sown oats or barley was almost always less (P < 0.05) than in conventional sowings. Per cent N in both cereals declined significantly between winter and spring

The New South Wales Tiger Flathead Neoplatycephalus macrodon (Ogilby). II. The Age Compositon of the Commercial Catch, Overfishing of the Stocks, and Suggested Conservation

1952 ◽  
Vol 3 (1) ◽  
pp. 1 ◽  
Author(s):  
WS Fairbridge
Keyword(s):  
New South ◽  
Age Groups ◽  
Fishing Ground ◽  
Alternative Measure ◽  
Age Group ◽  
Catch Per Unit Effort ◽  
Commercial Catch ◽  
Conservation Measure ◽  
South Wales ◽  
Post War

The commercial flathead catch is analysed into its component age-groups. The results are expressed in numbers and weight of each age-group caught in each month. The results indicate an absence of natural fluctuations in abundance of the year-groups during the series of years covered. The post-war decline in the catch of flathead is discussed in the light of this analysis. The catch has fallen from 5,700,000 lb. in 1944–45 to 2,100,000 lb. in 1948–49. The catch of flathead for a period between the wars is estimated at over 10,000,000 lb. per year. The stock of flathead has thus shown a failure to recover during the war-time rest, as well as a sudden fall with the inception of heavy fishing of recent years. Possible reasons for these changes in the flathead stock are discussed. It is suggested that the numbers of recruits are limited by the numbers of spawning adults. The results obtained from this work are fuller, but in entire agreement with those of the earlier paper on the trawlfishery as a xvliole. The adoption of conservation measures is urged. The trawlfishery is now dependent on two hitherto discarded species of poorer quality than the flathead, and the better of these is already showing a reduced catch per unit effort of fishing. The most important conservation measure is that suggested in the earlier paper — a reduction of the fleet to the equivalent of 13 trawlers. It is regarded as probable that if this step is not taken, the annual trawlfish catch will continue to decline. Closure of the Botany fishing ground is suggested as a further, but not an alternative, measure.

Distribution of the Platypus (Ornithorhynchus anatinus) in the Bombala River Catchment, South-Eastern New South Wales.

1998 ◽  
Vol 20 (2) ◽  
pp. 251
Author(s):  
R.W. Turnbull
Keyword(s):  
New South ◽  
New South Wales ◽  
River Catchment ◽  
South Eastern ◽  
South Wales ◽  
Ornithorhynchus Anatinus ◽  
The Difference

Distribution of the platypus (Ornithorhynchus anatinus) in the Bombala River catchment in south-eastern New South Wales was surveyed using questionnaires. Platypuses were reported from all streams in the catchment. The majority of positive sightings were from downstream areas whereas very few positive sightings were reported from headwater areas. The difference between frequencies of headwater and downstream reports of sightings was significant. The platypus was considered common throughout the catchment.

The impact of selecting for increased ewe fat level on reproduction and its potential to reduce supplementary feeding in a commercial composite flock

2016 ◽  
Vol 56 (4) ◽  
pp. 698 ◽  
Author(s):  
S. F. Walkom ◽  
F. D. Brien ◽  
M. L. Hebart ◽  
W. S. Pitchford
Keyword(s):  
Body Composition ◽  
Body Condition ◽  
New South ◽  
Supplementary Feeding ◽  
South Wales ◽  
Fat Level ◽  
Grazing Systems ◽  
Selection For ◽  
The Difference ◽  
The Impact

In southern Australian grazing systems, energy availability typically exceeds energy requirements. Grazing systems are likely to have higher profitability if ewes can utilise this relatively cheap feed by gaining more condition (muscle and fat) and then mobilising it when feed is expensive. The present paper focusses on the importance of genetic merit for fat on the lifetime productivity of the ewe within a commercial operation. The analysis was carried out on a maternal composite stud flock in Holbrook, New South Wales. Ultrasound fat and muscle depth were measured on 2796 ewes as lambs at post-weaning and as adult ewes, to determine the genetic relationship between young and adult body composition. The hypothesis of the paper is that selection for increased fat at young age will improve body condition of adult ewes, which will lead to improved reproduction and potentially reduced requirements for supplementary feeding. Given that the difference in feed cost between times of abundance and shortage is likely to be larger, the system may become more profitable despite being less efficient (owing to increased feed intake). Our results indicated that selection for scanned post-weaning fat and muscle depth in lambs should lead to increased fat muscle and body condition in the breeding ewe because of strong genetic correlation estimates between the post-weaning and adult traits of 0.68–0.99. The influence of body composition traits on reproduction (number of lambs weaned) within the stud flock was weak. However, it is hypothesised that by genetically increasing post-weaning fat depth in ewes, producers could improve profitability by reducing the demands for supplementary feeding.

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