639 resultados para Money market -- Australia -- Problems, exercises, etc.
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Parthenium (Parthenium hysterophorus L.), a major weed causing economic, environmental, and human and animal health problems in Australia and several countries in Asia, Africa, and the Pacific, has been a target for biological control in Australia since the mid-1970s. Nine species of insects and two rust fungi have been introduced as biological control agents into Australia. These include Carmenta sp. nr ithacae, a root feeding agent from Mexico. The larvae of C. sp. nr ithacae bore through the stem-base into the root where they feed on the cortical tissue of the taproot. During 1998-2002, 2,816 larval-infested plants and 387 adults were released at 31 sites across Queensland, Australia. Evidence of field establishment was first observed in two of the release sites in central Queensland in 2004. Annual surveys at these sites and nonrelease sites during 2006-2011 showed wide variations in the incidence and abundance of C. sp. nr ithacae between years and sites. Surveys at three of the nine release sites in northern Queensland and 16 of the 22 release sites in central Queensland confirmed the field establishment of C. sp. nr ithacae in four release sites and four nonrelease sites, all in central Queensland. No field establishment was evident in the inland region or in northern Queensland. A CLIMEX model based on the native range distribution of C. sp. nr ithacae predicts that areas east of the dividing range along the coast are more suitable for field establishment than inland areas. Future efforts to redistribute this agent should be restricted to areas identified as climatically favorable by the CLIMEX model.
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Non-Technical Summary Seafood CRC Project 2009/774. Harvest strategy evaluations and co-management for the Moreton Bay Trawl Fishery Principal Investigator: Dr Tony Courtney, Principal Fisheries Biologist Fisheries and Aquaculture, Agri-Science Queensland Department of Agriculture, Fisheries and Forestry Level B1, Ecosciences Precinct, Joe Baker St, Dutton Park, Queensland 4102 Email: tony.courtney@daff.qld.gov.au Project objectives: 1. Review the literature and data (i.e., economic, biological and logbook) relevant to the Moreton Bay trawl fishery. 2. Identify and prioritise management objectives for the Moreton Bay trawl fishery, as identified by the trawl fishers. 3. Undertake an economic analysis of Moreton Bay trawl fishery. 4. Quantify long-term changes to fishing power for the Moreton Bay trawl fishery. 5. Assess priority harvest strategies identified in 2 (above). Present results to, and discuss results with, Moreton Bay Seafood Industry Association (MBSIA), fishers and Fisheries Queensland. Note: Additional, specific objectives for 2 (above) were developed by fishers and the MBSIA after commencement of the project. These are presented in detail in section 5 (below). The project was an initiative of the MBSIA, primarily in response to falling profitability in the Moreton Bay prawn trawl fishery. The analyses were undertaken by a consortium of DAFF, CSIRO and University of Queensland researchers. This report adopted the Australian Standard Fish Names (http://www.fishnames.com.au/). Trends in catch and effort The Moreton Bay otter trawl fishery is a multispecies fishery, with the majority of the catch composed of Greasyback Prawns (Metapenaeus bennettae), Brown Tiger Prawns (Penaeus esculentus), Eastern King Prawns (Melicertus plebejus), squid (Uroteuthis spp., Sepioteuthis spp.), Banana Prawns (Fenneropenaeus merguiensis), Endeavour Prawns (Metapenaeus ensis, Metapenaeus endeavouri) and Moreton Bay bugs (Thenus parindicus). Other commercially important byproduct includes blue swimmer crabs (Portunus armatus), three-spot crabs (Portunus sanguinolentus), cuttlefish (Sepia spp.) and mantis shrimp (Oratosquilla spp.). Logbook catch and effort data show that total annual reported catch of prawns from the Moreton Bay otter trawl fishery has declined to 315 t in 2008 from a maximum of 901 t in 1990. The number of active licensed vessels participating in the fishery has also declined from 207 in 1991 to 57 in 2010. Similarly, fishing effort has fallen from a peak of 13,312 boat-days in 1999 to 3817 boat-days in 2008 – a 71% reduction. The declines in catch and effort are largely attributed to reduced profitability in the fishery due to increased operational costs and depressed prawn prices. The low prawn prices appear to be attributed to Australian aquacultured prawns and imported aquacultured vannamei prawns, displacing the markets for trawl-caught prawns, especially small species such as Greasyback Prawns which traditionally dominated landings in Moreton Bay. In recent years, the relatively high Australian dollar has resulted in reduced exports of Australian wild-caught prawns. This has increased supply on the domestic market which has also suppressed price increases. Since 2002, Brown Tiger Prawns have dominated annual reported landings in the Moreton Bay fishery. While total catch and effort in the bay have declined to historically low levels, the annual catch and catch rates of Brown Tiger Prawns have been at record highs in recent years. This appears to be at least partially attributed to the tiger prawn stock having recovered from excessive effort in previous decades. The total annual value of the Moreton Bay trawl fishery catch, including byproduct, is about $5 million, of which Brown Tiger Prawns account for about $2 million. Eastern King Prawns make up about 10% of the catch and are mainly caught in the bay from October to December as they migrate to offshore waters outside the bay where they contribute to a large mono-specific trawl fishery. Some of the Eastern King Prawns harvested in Moreton Bay may be growth overfished (i.e., caught below the size required to maximise yield or value), although the optimum size-at-capture was not determined in this study. Banana Prawns typically make up about 5% of the catch, but can exceed 20%, particularly following heavy rainfall. Economic analysis of the fishery From the economic survey, cash profits were, on average, positive for both fleet segments in both years of the survey. However, after the opportunity cost of capital and depreciation were taken into account, the residual owner-operator income was relatively low, and substantially lower than the average share of revenue paid to employed skippers. Consequently, owner-operators were earning less than their opportunity cost of their labour, suggesting that the fleets were economically unviable in the longer term. The M2 licensed fleet were, on average, earning similar boat cash profits as the T1/M1 fleet, although after the higher capital costs were accounted for the T1/M1 boats were earning substantially lower returns to owner-operator labour. The mean technical efficiency for the fleet as a whole was estimated to be 0.67. That is, on average, the boats were only catching 67 per cent of what was possible given their level of inputs (hours fished and hull units). Almost one-quarter of observations had efficiency scores above 0.8, suggesting a substantial proportion of the fleet are relatively efficient, but some are also relatively inefficient. Both fleets had similar efficiency distributions, with median technical efficiency score of 0.71 and 0.67 for the M2 and T1/M1 boats respectively. These scores are reasonably consistent with other studies of prawn trawl fleets in Australia, although higher average efficiency scores were found in the NSW prawn trawl fleet. From the inefficiency model, several factors were found to significantly influence vessel efficiency. These included the number of years of experience as skipper, the number of generations that the skipper’s family had been fishing and the number of years schooling. Skippers with more schooling were significantly more efficient than skippers with lower levels of schooling, consistent with other studies. Skippers who had been fishing longer were, in fact, less efficient than newer skippers. However, this was mitigated in the case of skippers whose family had been involved in fishing for several generations, consistent with other studies and suggesting that skill was passed through by families over successive generations. Both the linear and log-linear regression models of total fishing effort against the marginal profit per hour performed reasonably well, explaining between 70 and 84 per cent of the variation in fishing effort. As the models had different dependent variables (one logged and the other not logged) this is not a good basis for model choice. A better comparator is the square root of the mean square error (SMSE) expressed as a percentage of the mean total effort. On this criterion, both models performed very similarly. The linear model suggests that each additional dollar of average profits per hour in the fishery increases total effort by around 26 hours each month. From the log linear model, each percentage increase in profits per hour increases total fishing effort by 0.13 per cent. Both models indicate that economic performance is a key driver of fishing effort in the fishery. The effect of removing the boat-replacement policy is to increase individual vessel profitability, catch and effort, but the overall increase in catch is less than that removed by the boats that must exit the fishery. That is, the smaller fleet (in terms of boat numbers) is more profitable but the overall catch is not expected to be greater than before. This assumes, however, that active boats are removed, and that these were also taking an average level of catch. If inactive boats are removed, then catch of the remaining group as a whole could increase by between 14 and 17 per cent depending on the degree to which costs are reduced with the new boats. This is still substantially lower than historical levels of catch by the fleet. Fishing power analyses An analysis of logbook data from 1988 to 2010, and survey information on fishing gear, was performed to estimate the long-term variation in the fleet’s ability to catch prawns (known as fishing power) and to derive abundance estimates of the three most commercially important prawn species (i.e., Brown Tiger, Eastern King and Greasyback Prawns). Generalised linear models were used to explain the variation in catch as a function of effort (i.e., hours fished per day), vessel and gear characteristics, onboard technologies, population abundance and environmental factors. This analysis estimated that fishing power associated with Brown Tiger and Eastern King Prawns increased over the past 20 years by 10–30% and declined by approximately 10% for greasybacks. The density of tiger prawns was estimated to have almost tripled from around 0.5 kg per hectare in 1988 to 1.5 kg/ha in 2010. The density of Eastern King Prawns was estimated to have fluctuated between 1 and 2 kg per hectare over this time period, without any noticeable overall trend, while Greasyback Prawn densities were estimated to have fluctuated between 2 and 6 kg per hectare, also without any distinctive trend. A model of tiger prawn catches was developed to evaluate the impact of fishing on prawn survival rates in Moreton Bay. The model was fitted to logbook data using the maximum-likelihood method to provide estimates of the natural mortality rate (0.038 and 0.062 per week) and catchability (which can be defined as the proportion of the fished population that is removed by one unit of effort, in this case, estimated to be 2.5 ± 0.4 E-04 per boat-day). This approach provided a method for industry and scientists to develop together a realistic model of the dynamics of the fishery. Several aspects need to be developed further to make this model acceptable to industry. Firstly, there is considerable evidence to suggest that temperature influences prawn catchability. This ecological effect should be incorporated before developing meaningful harvest strategies. Secondly, total effort has to be allocated between each species. Such allocation of effort could be included in the model by estimating several catchability coefficients. Nevertheless, the work presented in this report is a stepping stone towards estimating essential fishery parameters and developing representative mathematical models required to evaluate harvest strategies. Developing a method that allowed an effective discussion between industry, management and scientists took longer than anticipated. As a result, harvest strategy evaluations were preliminary and only included the most valuable species in the fishery, Brown Tiger Prawns. Additional analyses and data collection, including information on catch composition from field sampling, migration rates and recruitment, would improve the modelling. Harvest strategy evaluations As the harvest strategy evaluations are preliminary, the following results should not be adopted for management purposes until more thorough evaluations are performed. The effects, of closing the fishery for one calendar month, on the annual catch and value of Brown Tiger Prawns were investigated. Each of the 12 months (i.e., January to December) was evaluated. The results were compared against historical records to determine the magnitude of gain or loss associated with the closure. Uncertainty regarding the trawl selectivity was addressed using two selectivity curves, one with a weight at 50% selection (S50%) of 7 g, based on research data, and a second with S50% of 14 g, put forward by industry. In both cases, it was concluded that any monthly closure after February would not be beneficial to the industry. The magnitude of the benefit of closing the fishery in either January or February was sensitive to which mesh selectivity curve that was assumed, with greater benefit achieved when the smaller selectivity curve (i.e., S50% = 7 g) was assumed. Using the smaller selectivity (S50% = 7 g), the expected increase in catch value was 10–20% which equates to $200,000 to $400,000 annually, while the larger selectivity curve (S50% = 14 g) suggested catch value would be improved by 5–10%, or $100,000 to $200,000. The harvest strategy evaluations showed that greater benefits, in the order of 30–60% increases in the tiger annual catch value, could have been obtained by closing the fishery early in the year when annual effort levels were high (i.e., > 10,000 boat-days). In recent years, as effort levels have declined (i.e., ~4000 boat-days annually), expected benefits from such closures are more modest. In essence, temporal closures offer greater benefit when fishing mortality rates are high. A spatial analysis of Brown Tiger Prawn catch and effort was also undertaken to obtain a better understanding of the prawn population dynamics. This indicated that, to improve profitability of the fishery, fishers could consider closing the fishery in the period from June to October, which is already a period of low profitability. This would protect the Brown Tiger Prawn spawning stock, increase catch rates of all species in the lucrative pre-Christmas period (November–December), and provide fishers with time to do vessel maintenance, arrange markets for the next season’s harvest, and, if they wish, work at other jobs. The analysis found that the instantaneous rate of total mortality (Z) for the March–June period did not vary significantly over the last two decades. As the Brown Tiger Prawn population in Moreton Bay has clearly increased over this time period, an interesting conclusion is that the instantaneous rate of natural mortality (M) must have increased, suggesting that tiger prawn natural mortality may be density-dependent at this time of year. Mortality rates of tiger prawns for June–October were found to have decreased over the last two decades, which has probably had a positive effect on spawning stocks in the October–November spawning period. Abiotic effects on the prawns The influence of air temperature, rainfall, freshwater flow, the southern oscillation index (SOI) and lunar phase on the catch rates of the four main prawn species were investigated. The analyses were based on over 200,000 daily logbook catch records over 23 years (i.e., 1988–2010). Freshwater flow was more influential than rainfall and SOI, and of the various sources of flow, the Brisbane River has the greatest volume and influence on Moreton Bay prawn catches. A number of time-lags were also considered. Flow in the preceding month prior to catch (i.e., 30 days prior, Logflow1_30) and two months prior (31–60 days prior, Logflow31_60) had strong positive effects on Banana Prawn catch rates. Average air temperature in the preceding 4-6 months (Temp121_180) also had a large positive effect on Banana Prawn catch rates. Flow in the month immediately preceding catch (Logflow1_30) had a strong positive influence on Greasyback Prawn catch rates. Air temperature in the preceding two months prior to catch (Temp1_60) had a large positive effect on Brown Tiger Prawn catch rates. No obvious or marked effects were detected for Eastern King Prawns, although interestingly, catch rates declined with increasing air temperature 4–6 months prior to catch. As most Eastern King Prawn catches in Moreton Bay occur in October to December, the results suggest catch rates decline with increasing winter temperatures. In most cases, the prawn catch rates declined with the waxing lunar phase (high luminance/full moon), and increased with the waning moon (low luminance/new moon). The SOI explains little additional variation in prawn catch rates (~ <2%), although its influence was higher for Banana Prawns. Extrapolating findings of the analyses to long-term climate change effects should be interpreted with caution. That said, the results are consistent with likely increases in abundance in the region for the two tropical species, Banana Prawns and Brown Tiger Prawns, as coastal temperatures rise. Conversely, declines in abundance could be expected for the two temperate species, Greasyback and Eastern King Prawns. Corporate management structures An examination of alternative governance systems was requested by the industry at one of the early meetings, particularly systems that may give them greater autonomy in decision making as well as help improve the marketing of their product. Consequently, a review of alternative management systems was undertaken, with a particular focus on the potential for self-management of small fisheries (small in terms of number of participants) and corporate management. The review looks at systems that have been implemented or proposed for other small fisheries internationally, with a particular focus on self-management as well as the potential benefits and challenges for corporate management. This review also highlighted particular opportunities for the Moreton Bay prawn fishery. Corporate management differs from other co-management and even self-management arrangements in that ‘ownership’ of the fishery is devolved to a company in which fishers and government are shareholders. The company manages the fishery as well as coordinates marketing to ensure that the best prices are received and that the catch taken meets the demands of the market. Coordinated harvesting will also result in increased profits, which are returned to fishers in the form of dividends. Corporate management offers many of the potential benefits of an individual quota system without formally implementing such a system. A corporate management model offers an advantage over a self-management model in that it can coordinate both marketing and management to take advantage of this unique geographical advantage. For such a system to be successful, the fishery needs to be relatively small and self- contained. Small in this sense is in terms of number of operators. The Moreton Bay prawn fishery satisfies these key conditions for a successful self-management and potentially corporate management system. The fishery is small both in terms of number of participants and geography. Unlike other fisheries that have progressed down the self-management route, the key market for the product from the Moreton Bay fishery is right at its doorstep. Corporate management also presents a number of challenges. First, it will require changes in the way fishers operate. In particular, the decision on when to fish and what to catch will be taken away from the individual and decided by the collective. Problems will develop if individuals do not join the corporation but continue to fish and market their own product separately. While this may seem an attractive option to fishers who believe they can do better independently, this is likely to be just a short- term advantage with an overall long-run cost to themselves as well as the rest of the industry. There are also a number of other areas that need further consideration, particularly in relation to the allocation of shares, including who should be allocated shares (e.g. just boat owners or also some employed skippers). Similarly, how harvesting activity is to be allocated by the corporation to the fishers. These are largely issues that cannot be answered without substantial consultation with those likely to be affected, and these groups cannot give these issues serious consideration until the point at which they are likely to become a reality. Given the current structure and complexity of the fishery, it is unlikely that such a management structure will be feasible in the short term. However, the fishery is a prime candidate for such a model, and development of such a management structure in the future should be considered as an option for the longer term.
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This book provides for the first time a detailed host list for all the fruit fly species (Tephritidae) known from Australia. It includes available distribution, male lure and host plant information for the 278 species currently recorded from Australia (including Torres Strait Islands but excluding Christmas and Cocos (Keeling) islands in the Indian Ocean). This total includes 269 described species plus nine undescribed species of Tephritinae. Thirteen fruit fly specialists from throughout Australia collaborated with QDPI in the production of this book. It provides an invaluable reference source for anyone involved in fruit fly research, ecological studies, pre- and post-harvest control, regulation, quarantine and market access.
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Fruit size and quality are major problems in early-season stonefruit cultivars grown in Australia and South-East Asia. In Australia, Thailand and Vietnam, new training and trellising systems are being developed to improve yield and fruit quality. Australian trials found that new training systems, such as the Open Tatura system, are more productive compared with standard vase-trained trees. We established new crop-loading indices for low-chill stonefruit to provide a guide for optimum fruit thinning based on fruit number per canopy surface and butt cross sectional area. Best management practices were developed for low-chill stonefruit cultivation using growth retardants, optimizing leaf nitrogen concentrations and controlling rates and timing of irrigation. Regulated deficit irrigation (RDI) improved fruit sugar concentrations by restricting water application during stage II of fruit growth. New pest and disease control measures are also being developed using a new generation of fruit fly baits. Soft insecticides such as (Spinosad) are used at significantly lower concentrations and have lower mammalian toxicity than the organophosphates currently registered in Australia. In addition, fruit fly exclusion netting effectively eliminated fruit fly and many other insect pests from the orchard with no increase in diseases. This netting system increased sugar concentrations of peach and nectarine by as much as 30%. Economic analyses showed that the break-even point can be reduced from 12 to 6 years Open Tatura trellising and exclusion netting.
Genera of fungivorous Phlaeothripinae (Thysanoptera) from dead branches and leaf-litter in Australia
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An illustrated key is provided for the identification of 39 genera of Thysanoptera-Phlaeothripinae with species that live in association with dead branches and leaf-litter in Australia and are considered to be fungus-feeding. Seven of these gen-era are not previously recorded from this continent, including un-named species of Deplorothrips, Malacothrips, Mystro-thrips, Preeriella and Tylothrips, together with Azaleothrips lepidus Okajima and Terthrothrips ananthakrishnani Kudo. A brief generic diagnosis is provided for each genus, together with comments on systematic problems and numbers of species. Copyright © 2013 Magnolia Press.
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Given the limited resources available for weed management, a strategic approach is required to give the best bang for your buck. The current study incorporates: (1) a model ensemble approach to identify areas of uncertainty and commonality regarding a species invasive potential, (2) current distribution of the invaded species, and (3) connectivity of systems to identify target regions and focus efforts for more effective management. Uncertainty in the prediction of suitable habitat for H. amplexicaulis (study species) in Australia was addressed in an ensemble-forecasting approach to compare distributional scenarios from four models (CLIMATCH; CLIMEX; boosted regression trees [BRT]; maximum entropy [Maxent]). Models were built using subsets of occurrence and environmental data. Catchment risk was determined through incorporating habitat suitability, the current abundance and distribution of H. amplexicaulis, and catchment connectivity. Our results indicate geographic differences between predictions of different approaches. Despite these differences a number of catchments in northern, central, and southern Australia were identified as high risk of invasion or further spread by all models suggesting they should be given priority for the management of H. amplexicaulis. The study also highlighted the utility of ensemble approaches in indentifying areas of uncertainty and commonality regarding the species invasive potential.
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There is a long tradition of social inquiry concerned with locational patterns and place-based explanations of crime in which urban/rural differences have been regarded as of cardinal importance. The geographical and socio-spatial aspects of punishment have on the other hand been widely neglected. One reason for this is that cities have been treated as the site of the major crime problems, presenting a contrast with what are commonly assumed (often without careful empirical research) to be the naturally cohesive character of rural communities. Thus punishment, like crime, is not a significant or distinctive issue in rural communities, requiring the attention of criminologists. But just as there are significant and distinctive dimensions to rural crime, the practice of punishment in rural contexts raises important questions worthy of attention. These questions relate to (1) the demand for punishment (i.e. the penal sensibilities to be found in rural communities); (2) the supply of punishment according to principles of legal equality (notably the question of the effective availability in rural courts of the full range of penalties administered by urban courts, in particular alternatives to incarceration); and (3) the differential impact of the same penalties when imposed in different geographical settings (e.g. imprisonment may involve distant removal from an offender’s community in addition to segregation from it; license disqualification is a great deal more consequential in settings where public transport is unavailable). The chapter examines these questions by reference to available knowledge concerning patterns of punishment in rural Australia. This will be set against the background of an analysis of the differential social organisation of penality in rural and urban settings. The generally more attenuated nature of the social state and social provision in rural contexts can, depending upon the profile of particular communities (and in particular their degree of social homogeneity), produce very different penal consequences: more heavy reliance on the penal state on the one hand, or greater recourse to informal social controls on the other.
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Cotton bunchy top (CBT) disease has caused significant yield losses in Australia and is now managed by control of its vector, the cotton aphid (Aphis gossypii). Its mode of transmission and similarities in symptoms to cotton Blue Disease suggested it may also be caused by a luteovirus or related virus. Degenerate primers to conserved regions of the genomes of the family Luteoviridae were used to amplify viral cDNAs from CBT-affected cotton leaf tissue that were not present in healthy plants. Partial genome sequence of a new virus (Cotton bunchy top virus, CBTV) was obtained spanning part of the RNA-dependent-RNA-polymerase (RdRP), all of the coat protein and part of the aphid-transmission protein. CBTV sequences could be detected in viruliferous aphids able to transmit CBT, but not aphids from non-symptomatic plants, indicating that it is associated with the disease and may be the causal agent. All CBTV open-reading frames had their closest similarity to viruses of the genus Polerovirus. The partial RdRP had 90 % amino acid identity to the RdRP of Cotton leafroll dwarf virus (CLRDV) that causes cotton blue disease, while other parts of the genome were more similar to other poleroviruses. The sequence similarity and genome organization of CBTV suggest that it should be considered a new member of the genus Polerovirus. This partial genome sequence of CBTV opens up the possibility for developing diagnostic tests for detection of the virus in cotton plants, aphids and weeds as well as alternative strategies for engineering CBT resistance in cotton plants through biotechnology. © 2012 Australasian Plant Pathology Society Inc.
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Background Australian mothers consistently rate postnatal care as the poorest aspect of their maternity care, and researchers and policymakers have widely acknowledged the need for improvement in how postnatal care is provided. Aim To identify and analyse mothers’ comments about postnatal care in their free text responses to an open ended question in the Having a Baby in Queensland Survey, 2010, and reflect on their implications for midwifery practice and maternity service policies. Methods The survey assessed mothers’ experiences of maternity care four months after birth. We analysed free-text data from an open-ended question inviting respondents to write ‘anything else you would like to tell us’. Of the final survey sample (N = 7193), 60% (N = 4310) provided comments, 26% (N = 1100) of which pertained to postnatal care. Analysis included the coding and enumeration of issues to identify the most common problems commented on by mothers. Comments were categorised according to whether they related to in-hospital or post-discharge care, and whether they were reported by women birthing in public or private birthing facilities. Results The analysis revealed important differences in maternal experiences according to birthing sector: mothers birthing in public facilities were more likely to raise concerns about the quality and/or duration of their in-hospital stay than those in private facilities. Conversely, mothers who gave birth in private facilities were more likely to raise concerns about inadequate post-discharge care. Regardless of birthing sector, however, a substantial proportion of all mothers spontaneously raised concerns about their experiences of inadequate and/or inconsistent breastfeeding support. Conclusion Women who birth in private facilities were more likely to spontaneously report concerns about their level of post-discharge care than women from public facilities in Queensland, and publically provided community based care is not sufficient to meet women's needs. Inadequate or inconsistent professional breastfeeding support remains a major issue for early parenting women regardless of birthing sector.
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Tainting of outdoor pond-reared barramundi Lates calcarifer by muddy-earthy off-flavours is frequently reported across tropical Australia. To investigate the possible causes and effects of off-flavour tainting, we analysed water samples from outdoor rearing ponds for the presence of geosmin (GSM) and 2-methylisoborneol (2-MIB), 2 microbial metabolites often associated with tainting episodes. We then conducted controlled dose-effect experiments which measured the accumulation of tainting metabolites in the flesh, and the impact tainting had on taste and flavour attributes. GSM was deemed to be the compound most likely responsible for off-flavour tainting, persisting at moderate (similar to 1.00 mu g l(-1)) to extreme levels (similar to 14.36 mu g l(-1)), while 2-MIB was never detected during the study. Controlled experiments revealed that the accumulation of GSM in the flesh of market-sized barramundi was directly related to GSM levels of the holding water (0 to similar to 4 mu g l(-1)), with higher levels resulting in significant increases in undesirable taste and flavour attributes, particularly muddy-earthy flavour and weedy aftertaste. We identified the sensory detection threshold for GSM in farmed barramundi to be <= 0.74 mu g kg(-1), similar to estimates for GSM detection in rainbow trout Oncorhynchus mykiss (similar to 0.9 mu g kg(-1)) and for 2-MIB in channel catfish Ictalurus punctatus (0.7 mu g kg(-1)). Quantitative estimation of flesh-bound GSM using gas chromatography-mass spectrometry (GC-MS) agreed well with human sensory assessment scores and highlights the reliability of chemical analysis of GSM in barramundi flesh while also indicating the value of GC-MS analysis in predicting the impact of GSM on the sensory properties of farmed barramundi.
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BACKGROUND: The recent development of very high resistance to phosphine in rusty grain beetle, Cryptolestes ferrugineus (Stephens), seriously threatens stored-grain biosecurity. The aim was to characterise this resistance, to develop a rapid bioassay for its diagnosis to support pest management and to document the distribution of resistance in Australia in 20072011. RESULTS: Bioassays of purified laboratory reference strains and field-collected samples revealed three phenotypes: susceptible, weakly resistant and strongly resistant. With resistance factors of > 1000 x , resistance to phosphine expressed by the strong resistance phenotype was higher than reported for any stored-product insect species. The new time-to-knockdown assay rapidly and accurately diagnosed each resistance phenotype within 6 h. Although less frequent in western Australia, weak resistance was detected throughout all grain production regions. Strong resistance occurred predominantly in central storages in eastern Australia. CONCLUSION: Resistance to phosphine in the rusty grain beetle is expressed through two identifiable phenotypes: weak and strong. Strong resistance requires urgent changes to current fumigation dosages. The development of a rapid assay for diagnosis of resistance enables the provision of same-day advice to expedite resistance management decisions. (c) 2012 Commonwealth of Australia. Published by John Wiley & Sons, Ltd.
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The leaf-tying moth Hypocosmia pyrochroma Jones (Lepidoptera: Pyralidae), a native of sub tropical South America, has been introduced as a biological control agent for cat’s claw creeper, Dolichandra unguis-cati (L.) Lohman (Bignoniaceae), in Australia and South Africa. So far there has been no evidence of its field establishment in either country. A narrow temperature tolerance is a potential limiting factor for the establishment of weed biological control insects in novel habitats. In this study, we evaluated the effect of seven constant temperatures (12–40 °C) on the survival and development of H. pyrochroma in temperature-controlled cabinets. Temperatures between 20 and 30 °C were the most favorable for adult survival, oviposition, egg hatching, and larval and pupal development. Adult survival (12–40 °C) and egg development (15–35 °C) showed tolerance for wider temperature ranges than oviposition, and larval and pupal development, which were all negatively affected by both high (>30 °C) and low (<20 °C) temperatures. The degree-day (DD) requirement to complete a generation was estimated as 877 above a threshold temperature of 12 °C. Based on DD requirements and an obligatory winter diapause of pupae from mid-autumn to mid-spring, the potential number of generations (egg to adult) the leaf-tying moth can complete in a year in Australia or South Africa range from one to three. A climate-matching model predicted that the inland regions of both Australia and South Africa are less favorable for H. pyrochroma than the coastal areas. The study suggested that H. pyrochroma is more likely to establish in the coastal areas of Australia where most of the cat’s claw creeper infestations occur, than in South Africa where most of the cat’s claw creeper infestations are inland.
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Loss of nitrogen in deep drainage from agriculture is an important issue for environmental and economic reasons, but limited field data is available for tropical crops. In this study, nitrogen (N) loads leaving the root zone of two major humid tropical crops in Australia, sugarcane and bananas, were measured. The two field sites, 57 km apart, had a similar soil type (a well drained Dermosol) and rainfall (∼2700 mm year -1) but contrasting crops and management. A sugarcane crop in a commercial field received 136-148 kg N ha -1 year -1 applied in one application each year and was monitored for 3 years (first to third ratoon crops). N treatments of 0-600 kg ha -1 year -1 were applied to a plant and following ratoon crop of bananas. N was applied as urea throughout the growing season in irrigation water through mini-sprinklers. Low-suction lysimeters were installed at a depth of 1 m under both crops to monitor loads of N in deep drainage. Drainage at 1 m depth in the sugarcane crops was 22-37% of rainfall. Under bananas, drainage in the row was 65% of rainfall plus irrigation for the plant crop, and 37% for the ratoon. Nitrogen leaching loads were low under sugarcane (<1-9 kg ha -1 year -1) possibly reflecting the N fertiliser applications being reasonably matched to crop requirements and at least 26 days between fertiliser application and deep drainage. Under bananas, there were large loads of N in deep drainage when N application rates were in excess of plant demand, even when applied fortnightly. The deep drainage loss of N attributable to N fertiliser, calculated by subtracting the loss from unfertilised plots, was 246 and 641 kg ha -1 over 2 crop cycles, which was equivalent to 37 and 63% of the fertiliser application for treatments receiving 710 and 1065 kg ha -1, respectively. Those rates of fertiliser application resulted in soil acidification to a depth of 0.6 m by as much as 0.6 of a unit at 0.1-0.2 m depth. The higher leaching losses from bananas indicated that they should be a priority for improved N management. Crown Copyright © 2012.
Resumo:
Despite compulsory mathematics throughout primary and junior secondary schooling, many schools across Australia continue in their struggle to achieve satisfactory numeracy levels. Numeracy is not a distinct subject in school curriculum, and in fact appears as a general capability in the Australian Curriculum, wherein all teachers across all curriculum areas are responsible for numeracy. This general capability approach confuses what numeracy should look like, especially when compared to the structure of numeracy as defined on standardised national tests. In seeking to define numeracy, schools tend to look at past NAPLAN papers, and in doing so, we do not find examples drawn from the various aspects of school curriculum. What we find are more traditional forms of mathematical worded problems.
Resumo:
In current simulation packages for the management of extensive beef-cattle enterprises, the relationships for the key biological rates (namely conception and mortality) are quite rudimentary. To better estimate these relationships, cohort-level data covering 17 100 cow-years from six sites across northern Australia were collated and analysed. Further validation data, from 7200 cow-years, were then used to test these relationships. Analytical problems included incomplete and non-standardised data, considerable levels of correlation among the 'independent' variables, and the close similarity of alternate possible models. In addition to formal statistical analyses of these data, the theoretical equations for predicting mortality and conception rates in the current simulation models were reviewed, and then reparameterised and recalibrated where appropriate. The final models explained up to 80% of the variation in the data. These are now proposed as more accurate and useful models to be used in the prediction of biological rates in simulation studies for northern Australia. © The State of Queensland (through the Department of Agriculture, Fisheries and Forestry) 2012. © CSIRO.