A decision support tool for parasite management in fish aquaculture

A decision support tool was developed to aid management of problematic parasites in marine fish aquaculture. The tool provides biologically relevant treatment intervals to interrupt the life cycle of ectoparasitic flatworms that occur in global kingfish and amberjack (Seriola spp.) aquaculture. Temperature-dependent life cycle parameters for the ‘skin flukes’, Benedenia seriolae and Neobenedenia girellae, and the ‘gill fluke’, Zeuxapta seriolae, were derived from published data and modelled using non-linear regressions. Increasing temperatures shortened the duration of most life cycle parameters of all parasites. Salinity had no effect on the timing of life cycle parameters but limited hatching success in hypo- and hypersaline conditions. The tool, named BeNeZe after the first two letters of each parasite genera, enables rapid determination of treatment intervals for two consecutive medicinal immersion or ‘bathing’ treatments—the first to kill adult flatworms attached to fish and the second to prevent maturity of new parasite recruits. As temperature increases, the interval between treatments and the ‘window’ within which the second treatment should be applied is reduced. The tool can be used for multi-species infections. The inclusion of parasite taxonomy, biology and behaviour as part of an integrated management strategy is reviewed. Available through an open access app, BeNeZe is intended to be applied in conjunction with farm biosecurity, surveillance, management measures and recognition of independent management units. BeNeZe can be used to reduce infection burdens, improve fish welfare and production and reduce treatment number and frequency

The personal and national costs of mental health conditions: impacts on income, taxes, government support payments due to lost labour force participation

<p>Abstract</p> <p>Background</p> <p>Mental health conditions have the ability to interrupt an individual's ability to participate in the labour force, and this can have considerable follow on impacts to both the individual and the state.</p> <p>Method</p> <p>Cross-sectional analysis of the base population of Health&WealthMOD, a microsimulation model built on data from the Australian Bureau of Statistics' <it>Survey of Disability, Ageing and Carers </it>and STINMOD, an income and savings microsimulation model was used to quantify the personal cost of lost income and the cost to the state from lost income taxation, increased benefits payments and lost GDP as a result of early retirement due to mental health conditions in Australians aged 45-64 in 2009.</p> <p>Results</p> <p>Individuals aged 45 to 64 years who have retired early due to depression personally have 73% lower income then their full time employed counterparts and those retired early due to other mental health conditions have 78% lower incomes. The national aggregate cost to government due to early retirement from these conditions equated to $278 million (£152.9 million) in lost income taxation revenue,$407 million (£223.9 million) in additional transfer payments and around $1.7 billion in GDP in 2009 alone.</p> <p>Conclusions</p> <p>The costs of mental health conditions to the individuals and the state are considerable. While individuals has to bear the economic costs of lost income in addition to the burden of the conditions itself, the impact on the state is loss of productivity from reduced workforce participation, lost income taxation revenue, and increased government support payments - in addition to direct health care costs.</p

The biology of the cosmopolitan fish parasite Neobenedenia girellae

Monogeneans are a fascinating parasite group to study. They can be harmful pathogens of finfish and display interesting relationships with their hosts making research on these species engaging from both ecological and economic perspectives. Neobenedenia (Family Capsalidae) Yamaguti, 1963, is a notable monogenean genus and is notorious for the large number of potential host species that the constituent parasite taxa are able to infect. The distinct lack of research on Neobenedenia biology and the diversity of species present in Australian waters presented me with an opportunity to conduct a series of research studies designed to improve understanding of this parasite genus. The aim of this thesis was to provide an in-depth investigation of Neobenedenia phylogenetics and detailed biology (including the growth, morphology, reproduction, and biochemistry) of the species in Australia. The first data chapter (Chapter 2) determined the phylogenetic relationships between 33 Neobenedenia isolates by amplifying three genes; two nuclear (H3 and 28S rDNA) and one mitochondrial (cytochrome b). Isolates were collected from a total of 23 host species and nine countries in both hemispheres and included 16 isolates from 12 host fishes in Australia. Representative samples for Neobenedenia melleni MacCallum, 1927, Neobenedenia pacifica Bravo-Hollis, 1971, and Neobenedenia longiprostata Bravo-Hollis, 1971, formed discrete clades and collectively accounted for seven of the 33 samples used in this study. The remaining 26 isolates formed a single clade genetically distinct from all representative specimens. Morphological observation of these 26 isolates confirmed that they were morphologically indistinguishable from N. melleni despite displaying clear genetic differences in the phylogenetic trees. This confirmed the suggestion by the scientific community that Neobenedenia girellae Hargis, 1955, a species that was synonymised with N. melleni in 1996, should be reinstated as its own taxon, a recommendation that is encouraged by the authors. The second data chapter (Chapter 3) focussed on the effect that a number of environmental variables had on the morphology of N. girellae. Neobenedenia girellae is extremely flexible in the morphology it exhibits. Temperature was identified as the strongest factor affecting the morphology of this species, however, there was an indication that morphology may also be dictated by the host species that the parasite attaches to. Between different host species, parasites exhibited changes in the morphology of the attachment organs which come in direct contact with their host's surface. This is proposed to be a function of maximising the ability of their attachment organs to the scale/mucus interface of heterogeneous host surfaces. The morphology of parasites attached to the same host species at different temperatures differed most in their total body size. Features associated with the attachment of the parasite to the host did not differ which is likely a product of the homogenous host surface available to the parasite. The variation observed in this species explains why N. melleni and N. girellae have been misidentified, fuelling considerable taxonomic confusion in Neobenedenia in the past. The third data chapter (Chapter 4) focussed on elucidating reproductive and life cycle biology of N. girellae in temperatures and salinities typical of tropical regions. Neobenedenia girellae completed its life cycle almost twice as fast in warm, high saline conditions compared to cooler temperatures. Hatching and infection success and oncomiracidia longevity was significantly reduced in salinities less than 22 ‰ compared to higher saline conditions (35 and 40 ‰). A total of two strategically timed treatments on stock was recommended in cool to moderate temperatures in salinities of seawater or higher. In warmer conditions (> 30 ºC), a third treatment of stock is required as parasites reach sexual maturity faster than the time taken for all eggs to hatch in a given period. The development of an accessible and user-friendly strategic treatment timetable informs fish farmers and aquarists alike when to treat their fish to maximise the efficacy of treatments and minimise labour costs and reinfection. The fourth data chapter investigated the feasibility of collecting sufficient quantities of N. girellae eggs for biochemical analysis (Chapter 5). An established laboratory culture of N. girellae was optimised to enable the production of larger quantities of eggs over short periods of time for collection and subsequent biochemical analysis. Eggs were found to be composed primarily of water (79.12 %) followed by protein (11.51 %) and lipid (2.50 %). Lipids were composed of approximately equal amounts of saturated, monounsaturated, and polyunsaturated fatty acids (35.43 ± 0.38 %, 29.08 ± 0.38 %, and 35.50 ± 0.53 %, respectively). The predominant lipid classes were phosphatidylcholine (21.90 ± 1.42 %) and triacylglycerols (TAG) (33.82 ± 1.20 %). This is the first study to quantify the biochemical components of marine monogenean eggs but only provided insight into the biochemical contents of N. girellae eggs after they had been laid and not throughout development. Chapter 6 expanded on the topics identified in Chapter 5 and quantified the biochemical contents of eggs throughout embryogenic development and across a range of temperatures. This provided valuable information on metabolic fuels employed by embryos as they developed and in different environments. Additionally, reproductive biology (fecundity, egg-laying period, and egg volume) was investigated to provide a complete picture of N. girellae reproductive investment. Adult parasites were significantly larger at cooler temperatures and produced significantly larger eggs towards the end of their reproductive lives. Fecundity of adults was highest at 20 and 30 ºC compared to 25 ºC. The biochemistry of freshly laid eggs was similar to the results observed in Chapter 5. Proximate composition of eggs did not significantly change over the three temperatures tested, however, warmer temperatures resulted in the significant decrease in a number of mono- and polyunsaturated fatty acids throughout embryogenesis. The most prolific lipid classes were phospholipids and TAGs. The most notable change from the biochemical profile observed in Chapter 5 was that the amount of acetone mobile polar lipids in eggs more than doubled in the present study to compose up to 25% of the lipids in N. girellae eggs. Neobenedenia girellae is a parasite with a turbulent taxonomic history. Now that appropriate genes have been recognised that can accurately identify this species, potentially misidentified samples from previous studies can be clarified and the geographic and host records can be built on a solid foundation. This allows for future research to confidently credit any biological research to this taxon which has important implications for modelling populations on hosts, epidemiology, and management of this species on dozens of host taxa. If, as predicted, parasites and pathogens become a more immediate problem for global food security in a rapidly changing climate, accurately defining and identifying threats and developing methods for management and eradication of these species is paramount. This thesis presents a comprehensive assessment of one of the most cosmopolitan monogenean species in the world and the intimate knowledge generated on its biology can be used to reduce the impact of outbreaks on food fish production

The spatial dimension of Aboriginal land tenure

The unique relationship Aboriginal peoples have with the land has been highlighted in recent years with the passing of the Native Title Act 1993. The vastly different characteristics of Aboriginal land tenure to the Australian Torrens systems makes it difficult for the integration of the two tenure systems into one land registration system. A better understanding of Aboriginal land tenure and associated boundary definition is a vital first step towards mapping and documenting boundaries for the purposes of resolving native title disputes and developing institutional infrastructures that can better address the duality of tenure systems. Aboriginal land tenure boundaries have been mapped in the past by various anthropologists and historians. Mapping and definition of Aboriginal land boundaries by 'surveyors' are likely to provide alternative ways in which native title boundaries are determined, offering a different perspective on the spatial extent of Aboriginal land tenure. There is a need to accurately and unambiguously define the spatial extent of native title within the Australian cadastral system to support land based infrastructure and the future of native title. The paper highlights: • The characteristics and similarities/differences between the two tenure systems in a spatial context; • The current methods employed in defining and mapping Aboriginal land tenure boundaries and the appropriateness for the purpose of native title determination; • Possible ways in which Aboriginal land tenure could be defined and mapped in the future; and • Possible incorporation of Aboriginal land tenure into the current land administration and land registration systems of Australia.1- 6 November 199

An extended description of Pseudomys novae–hollandiae, with remarks on its affinity to P. hermannsburgensis

Volume: 9Start Page: 9End Page: 1

The spatial dimensions of native title

Deposited with permission of the author. © 2000 Clare BrazenorThe importance currently placed on sustainable development recognises the fundamental role of land administration and the management of land based resources. This acknowledgement of the pivotal role of land administration and tenure security reinforces the need to recognise all interest and responsibilities in land, particularly those of a customary and traditional nature. The United Nations Draft Declaration on the Rights of Indigenous Peoples (Pritchard 1998) respects the unique relationship between indigenous people(s) and the land, recognising the need to protect these traditions and cultures. A number of countries (specifically the United States of America, Canada and New Zealand) have implemented legal and institutional mechanisms for the recognition of this unique relationship and connection to land. In doing so it provided the precedent for the recognition of interests in land as held by indigenous peoples of Australia. In Australia the legal recognition of indigenous interests in land occurred in 1992, with the passing of the High Court’s decision concerning Mabo and others v the State of Queensland (no.2) (1992) 175 CLR 1 and the subsequent development and implementation of the Native Title Act 1993 (Cth). This federal act provides for the recognition and protection of native title within the framework of the Australian legal system . Its (native title interests) origins and foundations are those of traditional laws, connecting indigenous Australians with land and waters (S223 NTA 1993). (For complete abstract open document

A revision of the Australian jerboa mice

Volume: 8Start Page: 74End Page: 8

Amphibians and reptiles [Snowy River Region]

Volume: 15Start Page: 156End Page: 15