Response to ‘The predominantly fresh history of Lake Alexandrina, South Australia, and its implications for the Murray–Darling Basin Plan: a comment on Gell (2020)'

2020 ◽  
Vol 26 (3) ◽  
pp. 215 ◽  
Author(s):  
Thomas Hubble ◽  
Anna Helfensdorfer ◽  
Hannah Power
Keyword(s):  
South Australia ◽  
Murray Darling Basin ◽  
History Of

scholarly journals The predominantly fresh history of Lake Alexandrina, South Australia, and its implications for the Murray–Darling Basin Plan: a comment on Gell (2020)

2020 ◽  
Vol 26 (2) ◽  
pp. 142 ◽  
Author(s):  
John Tibby ◽  
Deborah Haynes ◽  
Kerri Muller
Keyword(s):  
Sediment Cores ◽  
South Australia ◽  
Minor Component ◽  
Environmental Water ◽  
Freshwater Ecosystem ◽  
European Settlement ◽  
Murray Darling Basin ◽  
History Of ◽  
The Subject ◽  
A Minor

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.

Mission Tracks in the Bush

2019 ◽  
Vol 3 (1-2) ◽  
pp. 103-124
Author(s):  
Gemma Tulud Cruz
Keyword(s):  
Nineteenth Century ◽  
Western Australia ◽  
South Australia ◽  
Nation Building ◽  
Cultural Encounters ◽  
History Of

Christian missionaries played an important role in the Australian nation building that started in the nineteenth century. This essay explores the multifaceted and complex cultural encounters in the context of two aboriginal missions in Australia in the nineteenth century. More specifically, the essay explores the New Norcia mission in Western Australia in 1846-1900 and the Lutheran mission in South Australia in 1838-1853. The essay begins with an overview of the history of the two missions followed by a discussion of the key faces of the cultural encounters that occurred in the course of the missions. This is followed by theological reflections on the encounters in dialogue with contemporary theology, particularly the works of Robert Schreiter.

The Status of the School Shark Fishery in South-Eastern Australian Waters

1959 ◽  
Vol 10 (2) ◽  
pp. 150 ◽  
Author(s):  
AM Olsen
Keyword(s):  
Maximum Yield ◽  
Reproductive Potential ◽  
South Australia ◽  
Slow Growth Rate ◽  
South Eastern ◽  
Pregnant Females ◽  
The Status ◽  
History Of ◽  
Annual Total ◽  
The Mean

The maximum yield of the school shark fishery in south-eastern Australian waters was 4.09 million lb in 1949. The catch has fluctuated since then about a declining trend to 3.18 million lb in 1956. In 1944, 7.3 hooks were required to catch a shark of mean weight 14.7 lb. In 1956 the number of hooks required was almost doubled: 13.6 hooks were needed to catch sharks of mean weight 13.7 lb; the catch per hook dropped from 2.01 to 0.99 lb. Whereas the catch per boat-month remained relatively stable at 4765 lb for 1944 and 4643 for 1956, the number of hooks used per boat-month increased from 2366 to 4668 hooks in 12 years. Throughout this period the mean weight of sharks in eastern Bass Strait remained fairly steady (11-13 lb) whereas there was a drop of 3 lb from a mean weight of 17-20 lb in the predominantly mature portion of the stock in western Bass Strait. Fishermen in South Australia have reported a comparable drop in the mean weight of sharks in their catches. During the period 1941-46 there was unrestricted inshore fishing of juveniles and pregnant females with a consequent severe drop in the inshore population. The subsequent decline in the annual total catch is believed to be due not only to a too intensive offshore fishery but also to the resultant reduced recruitment and depressed reproductive potential caused by the earlier destruction of juveniles and pregnant females. In the data presented in this paper there is evidence that the school shark fishery, which is operating on a single stock of sharks with a slow growth rate, a late sexual maturity, and a low fecundity, shows trends which are suggestive of depletion. Because similar trends in the soupfin shark fishery of California and in the dogfish fishery of British Columbia were followed by depletion, it has been inferred that regulations to protect the vulnerable phases of the life history of the school shark of Australia may be required. Measures for conservation are discussed.

Freshwater, Fish and the Future: Proceedings of the Global Cross-Sectoral Conference

2016 ◽  
Keyword(s):  
Environmental Flows ◽  
Economic Valuation ◽  
Assessment Method ◽  
Fiscal Constraints ◽  
Use Of Data ◽  
Recreational Fishery ◽  
Murray Darling Basin ◽  
History Of ◽  
Harvest Data ◽  
Murray Cod

<em>Abstract</em> .—The collection and use of data to manage the freshwater fisheries of Australia’s Murray–Darling basin (MDB) has a poor history of success. While there was limited assessment data for early subsistence and commercial fisheries, even after more robust data became available during the 1950s its quality varied across jurisdictions and was often poorly collated, assessments were not completed, and the data were underutilized by management. The fishery for Murray Cod <em>Maccullochella peelii </em> is given as an example, where the fishery declined to the point of closure and then the decline continued to the extent that Murray Cod was listed as a threatened species and all harvest now only occurs through the recreational fishery. Lessons from such poor population assessments have not been fully learned, however, as there remains a paucity of harvest data for this recreational fishery. Without a proper assessment, a true economic valuation of this fishery has not been made. As the MDB is Australia’s food bowl, there are competing demands for water use by agriculture, and without a proper assessment of the worth of the fishery, it is difficult for Murray Cod to be truly considered in either economic or sociopolitical discussions. The poor state of MDB rivers and their fish populations (including Murray Cod) has, however, resulted in political pressure for the development of the sustainable rivers audit, a common assessment method for riverine environmental condition monitoring. This audit undertakes standardized sampling for fish and a range of other variables at a number of fixed and randomly selected sites on a 3-year rotating basis. While the sustainable rivers audit has provided a range of data indicating that the condition of rivers is generally very poor, these data have yet to be fully utilized to determine the potential state of the fisheries (such as Murray Cod) or to set targets for rehabilitation, such as for environmental flows. While, to date, data analyses have been somewhat restricted by fiscal constraints, more comprehensive use of data, together with full fishery valuations, should be seen as the way forward for improved management.

P1943Ambient temperature and seasonal effects on blood pressure in 2.6 million Australians

2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
E Atkins ◽  
Q Pilard ◽  
K Rogers ◽  
A Salam ◽  
A Rodgers
Keyword(s):  
Blood Pressure ◽  
Seasonal Variation ◽  
Ambient Temperature ◽  
Medication Use ◽  
South Australia ◽  
Seasonal Effects ◽  
Lipid Lowering ◽  
Maximum Temperature ◽  
History Of ◽  
The Mean

Abstract Background There is evidence that blood pressure (BP) levels vary considerably from season to season, due principally to variation in ambient temperature. This gives the potential for both under- and over-treatment if BP lowering medications are not varied seasonally, but is not acknowledged in clinical guidelines. We will describe the seasonal variation in BP and assess the association between systolic blood pressure (SBP) and outdoor maximum ambient temperature in Australia. Methods The primary care data is an extract from MedicineInsight, a national general practice data program developed and managed by NPS MedicineWise, which extracts deidentified data from almost 10% of all Australian general practices. We included patients aged 30–90 years with at least one BP measure recorded from 1 Jan 2010 to 1 Aug 2017. Australian Bureau of Meteorology daily max temperature is linked by matching observation dates and location to nearest weather station. Decomposition of the mean will determine seasonal variation. Multiple linear regression was used to estimate the associations between max temperature and SBP with adjustment for age, sex, socioeconomic index, current smoking, comorbidities, BP lowering medication use, lipid lowering medication use and year of BP measurement. Results The study population includes 2.6 million people, mean age 55 years (standard deviation [SD] 16.3). Fifty-five percent are female, over a third of the cohort reside in New South Wales, and 62.4% reside in major Australian cities. The mean (SD) temperature was 23°C (6.6). There was a mean (SD) of 7 (11.4) BP measurements per person over the study period, median 3 measures (interquartile range 1–8). A quarter had a history of hypertension, 8% had a history of cardiovascular disease, and 8% had a history of diabetes. Twenty-six percent had at least one prescription for BP lowering therapy. The average monthly SBP for the cohort demonstrated strong seasonal variation with higher values in winter. The population mean varies by 3mmHg SBP between seasons across Australia, ranging from 1.7mmHg in the Northern Territory to 3.5mmHg in South Australia (range of mean maximum temperature 3°C [30–33] and 14°C [15–29] for the capital cities respectively). Each 10°C increase in max outdoor temperature was associated with a 1.8mmHg [95% CI 1.80–1.83] lower mean SBP. The proportion of people with SBP>140mmHg varied by season, irrespective of age, sex and use of BP lowering treatment. For example, among those treated control rates varied between 70 and 81%, and among those not treated between 78 and 85% (Figure). Blood pressure seasonality in Australia Conclusions BP control rates vary considerably by season. These findings have implications for the reliable diagnosis of hypertension, and suggest seasonal adjustments in treatment should be considered for some patients. The clinical and public health relevance of this phenomenon is expected to increase with increasing climate variability. Acknowledgement/Funding National Health and Medical Research Council Australia, National Heart Foundation Australia

Settlement and recruitment of the abalone Haliotis cyclobates Péron, 1816

1999 ◽  
Vol 50 (3) ◽  
pp. 229
Author(s):  
Jonathon Stevenson ◽  
Andrew Melville
Keyword(s):  
Life History ◽  
Early Life ◽  
Seagrass Meadow ◽  
South Australia ◽  
Early Life History ◽  
Hard Substratum ◽  
Abalone Species ◽  
History Of ◽  
Settlement Behaviour ◽  
Hard Substrata

The settlement preference, distribution and juvenile recruitment distribution of Haliotis cyclobates were investigated in a seagrass meadow in Gulf St Vincent, South Australia, in 1993 and 1994. Samples of hard substratum and seagrass were collected from seagrass patches and open areas and examined for newly settled and 0+ recruits. Hard substrata consisted of small rocks, large bivalve shells and bottles. Twelve newly settled recruits (<3 mm) were found: 11 on seagrass and one on hard substratum. Settlement onto seagrass blades is the first field example of an abalone species settling naturally onto soft substratum. 0+ recruits (4–9 mm) were found from March to October, indicating a single spawning and settlement season. 0+ recruits were found on small isolated patches of hard substratum in open and seagrass areas, suggesting that post-settlement migration may have some influence on recruitment patterns. The results indicate that the early life history of Haliotis cyclobates is adapted for enhancing recruitment into seagrass areas. Settlement onto seagrass blades is different from that observed for other species of abalone, and clarification of the specific settlement cue may contribute to the understanding of abalone settlement behaviour.

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