What are the economic prospects of developing aquaculture in Queensland to supply the low price white fillet market? Lessons from the US channel catfish industry

The farming of channel catfish (Ictalurus punctatus) is the largest (by volume and value) and most successful (in terms of market impact) aquaculture industry in the United States of America. Farmed channel catfish is the most consumed (in terms of volume per capita) fish fillet in the U.S. market. Within Australia, it has long been suggested by researchers and industry that silver perch (Bidyanus bidyanus) and possibly other endemic teraponid species possess similar biological attributes for aquaculture as channel catfish and may have the potential to generate a similar industry. The current teraponid industry in Australia, however, shows very little resemblance to the catfish industry, either in production style or market philosophy. A well established budget framework from the literature on U.S. channel catfish farming has been adapted for cost and climate conditions of the Burdekin region, Queensland, Australia. Breakeven prices for the hypothetical teraponid farms were found to be up to 50% higher than those published for catfish farms however were much lower than those reported for silver perch production in Australia using current, endemic styles of production. The breakeven prices for the hypothetical teraponid farms were most sensitive (in order of significance) to feed prices, production rates, interest rates, fingerling prices and electricity prices. At equivalent feed costs the costs of production between the hypothetical catfish farms in the Mississippi, U.S. and the hypothetical teraponid farms in the Burdekin, Australia were remarkably similar. The cost of feeds suitable for teraponid production in Australia are currently around double that of catfish feeds in the U.S. Issues currently hindering the development of a large scale teraponid industry in Australia are discussed.

The status of the genera Hysterolecithoides Yamaguti, 1934, Neotheletrum Gibson & Bray, 1979 and Machidatrema Leon-Regagnon, 1998 (Digenea : Hemiuroidea), including a description of M. leonae n. sp from Australian waters

A diagnosis is given for the lecithasterid genus Hysterolecithoides Yamaguti, 1934, which is now found to have two to six (possibly seven) vitelline masses. The species H. frontilatus (Manter, 1969) is returned to the genus, having been considered a member of the bunocotylid genus Neotheletrum by recent authors. It is redescribed from Siganus nebulosus, Moreton Bay, and S. doliatus, Lizard Island, Great Barrier Reef and New Caledonia, with emphasis on the presence of Juel's organ, a uterine seminal receptacle and the blind sac associated with the genital atrium. It differs from its congeners in the trajectory of the pars prostatica which recurves dorsally to the sinus-sac. Oligolecithoides Shen, 1982 is synonymised with Hysterolecithoides and O. trilobatus Shen, 1982 is synomised with H. epinepheli Yamaguti, 1934. Machidatrema Leon-Regagnon, 1998 is diagnosed, and found to be close to Hysterolecithoides, but differs in the lack of a blind-sac projecting from the dorsal genital atrium, by its tandem testes, the coiling of the uterus between the testes and the ovary, and the ventral excretory pore. M. leonae n. sp. is described from Siganus fuscescens, S. lineatus, S. doliatus, S. corallinus, S. vulpinus and Scarus globiceps at Heron Island, Queensland. It differs from its closest congener, M. akeh, in the muscular and tegumental flap over the genital pore and details of the terminal genitalia. M. chilostoma (Machida, 1980) and M. kyphosi (Yamaguti, 1970) are redescribed from Kyphosus vaigiensis from Heron Island. Neotheletrum Gibson & Bray, 1979 is diagnosed: it differs from Hysterolecithoides in its confluent excretory arms, blind seminal receptacle (no Juel's organ) and uniformly tripartite vitellarium. A cladistic analysis suggests that M. chilostoma and M. kyphosi are not best accommodated in Machidatrema, that Machidatrema (sensu stricto) is monophyletic and that Hysterolecithoides is paraphyletic. Hysterolecithoides and Machidatrema are considered hysterolecithine lecithasterids, whilst Neotheletrum is retained as an opisthadenine bunocotylid.

Does ecotourism contribute to sea turtle conservation? Is the flagship status of turtles advantageous?

There is little doubt that marine turtles are a flagship species for wildlife tourism. In some cases, this has turned out to be liability for sea turtle conservation, but in other cases, where for example turtle-based ecotourism has been developed, it has made a positive contribution to turtle conservation. Examples of both cases are given. Particular attention is given to the development of turtle-based ecotourism at Mon Repos Beach near Bundaberg, Australia. This development is set in its historical context and its contribution to conservation is discussed. Headstart projects for sea turtles in Sri Lanka are a tourist attraction. While they are promoted as having positive conservation consequences and a survey indicates that visitors are on the whole convinced of this, their effects on turtle conservation is uncertain. The farming of sea turtles provides a basis for tourism and can contribute to turtle conservation in ways outlined. It is argued that insufficient attention has been given to legends, culture and history associated with sea turtles in the promotion of turtle-based tourism. This is supported by Australian evidence. Insufficient use has been made of the connections of indigenous Australians with sea turtles in turtle-based tourism. Beneficial scope exist for developing connections between man and turtles further than at present in promoting turtle-based tourism. This could add further to the role of turtle-based tourism in promoting turtle conservation.

Marital status, farm size and other influences on the extent of cash cropping in Kenya: A household case study

This article examines the effects of marital status, farm size and other factors on the extent of cash cropping (and allocation of land use) by means of a case study in the Nyeri district in Kenya. It was found that married women are involved in the production of a relatively greater amount of output of cash crops than unmarried women since husbands prefer to have more land under cash crops than food crops. Farmers with better quality land allocate a high proportion of it to non-food cash crops, which may expose some households to greater risks of possible famine. The proportion of land allocated to food crops declines as the farm size increases while the proportion of land allocated to non-food cash crops rises as the size of farm increases. Age is also inversely associated with subsistence. Education, though inversely associated with subsistence farming does not appear to be statistically very significant as an influence on the composition of land use and composition of farm output. With growing commercialisation, married women work more hours than unmarried ones, working not only on non-cash food crops but also on non-food cash crops. Married women seem to lose their decision-making ability with growth of agricultural commercialisation, as husbands make most decisions to do with cash crops. Married women in Kenya also have little or no power to change the way land is allocated between food and non-food cash crops.

Management, conservation and farming of saltwater crocodiles: An Australian case study of sustainable commercial use

Opinions differ about what types of policies are likely to be most effective in conserving wildlife species. For example, the Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES) is based on the premise that curbing the commercial use of endangered species favours their conservation, whereas the Convention on Biological Diversity envisages the possibility that such use may contribute to the conservation of species. In Australia, as illustrated in the case of the saltwater crocodile (Crocodylus porosus), the governments of the Northern Territory and Western Australia have favoured the latter policy in recent years, whereas Queensland has favoured the former approach. The saltwater crocodile management plan of the Northern Territory provides an instructive case study of the consequences of adopting a commercial use strategy to promote wildlife conservation. The methodology used in this study, which involves a survey of crocodile farm managers and managers of cattle properties in the Northern Territory as well as secondary data, is outlined, after providing background on the conservation status of saltwater crocodiles in Australia and the saltwater crocodile management plan of the Northern Territory. In the results section, after outlining the nature and structure of the Northern Territory crocodile farming industry, evidence is presented on whether or not the crocodile management plan of the Northern Territory encourages pastoralists to conserve crocodiles on their properties. This study concludes with a discussion of the overall conservation effectiveness of the crocodile management scheme of the Northern Territory and considers its possible implications for saltwater crocodile management in areas of Asia where the species occurs.

A Report on the Managment of Saltwater Crocodiles (Crocodylus porosus) in the Northern Territory: Results of a Survey of Pastoralists

The management of saltwater crocodiles (Crocodylus porosus) in the Northern Territory is an important component of the State’s wildlife management policy. It encompasses saltwater crocodile control (the removal of problem crocodiles dangerous to humans and livestock), and the regulation of harvesting, farming and ranching of saltwater crocodiles for the production of commercial products. The distribution of saltwater crocodiles and their habitats often extend onto private and communal lands along the coastal belt of the Northern Territory, and therefore are a concern of landholders both Aboriginal and pastoral. This report presents the findings of a study of managers of Northern Territory cattle properties (pastoralists). Their attitudes are surveyed towards saltwater crocodiles on their properties and their views of the Northern Territory Parks and Wildlife Commission’s saltwater crocodile management plan are outlined. This report addresses social, economic and environmental aspects of the issue: pastoralists’ attitudes towards saltwater crocodiles in general, the impact saltwater crocodiles have on their cattle-raising business, their opinions of the Northern Territory Government’s saltwater crocodile plan and its operation, and their views of saltwater crocodile harvesting, its potential as an income earner and its contribution to the conservation of the saltwater crocodile. Opinions of pastoralists about new management schemes such as trophy hunting of saltwater crocodiles are also analysed. A concluding statement ties up the findings of the study and provides a snapshot of the current views of pastoral landholders of saltwater crocodiles and their management in the Northern Territory.

Growth and hard tissue remodelling in the dentition of the Australian lungfish, Neoceratodus forsteri (Osteichthyes: Dipnoi)

The extant lungfish, including three genera, the Australian, South American and African lungfishes, retain a dentition that appeared first in the Devonian, in some of the oldest members of this group. The dentition consists of permanent tooth plates with persistent cusps that appear early in development of the fish. The cusps, separate early in development, form ridges that are arranged in a radiating pattern, and fusion of the cusps to each other and to the underlying jaw bone produces a tooth plate. The lungfish dentition is based on a template of mantle dentine that surrounds bone trabeculae enclosed in the tooth plate. The mantle layer is covered by enamel. In most derived dipnoans, this framework encloses two further forms of dentine, known as interdenteonal and circumdenteonal dentines. The tooth plates grow in area and in depth without evidence of macroscopic resorption of dentines or of enamel. Increase in size and changes in shape of lungfish tooth plates is actually achieved by a process involving microscopic remodelling of the bone contained within the margin of each tooth plate, and the later addition of new dentines and enamel within and around the bone. This is accomplished without creating weakness in the structural integrity of the tooth plate and bone complex, and proceeds in line with growth and remodelling of the jaw bones attached to the tooth plates.

Infusing the use of seasonal climate forecasting into crop management practice in North East Australia using discussion support software

Seasonal climate forecasting offers potential for improving management of crop production risks in the cropping systems of NE Australia. But how is this capability best connected to management practice? Over the past decade, we have pursued participative systems approaches involving simulation-aided discussion with advisers and decision-makers. This has led to the development of discussion support software as a key vehicle for facilitating infusion of forecasting capability into practice. In this paper, we set out the basis of our approach, its implementation and preliminary evaluation. We outline the development of the discussion support software Whopper Cropper, which was designed for, and in close consultation with, public and private advisers. Whopper Cropper consists of a database of simulation output and a graphical user interface to generate analyses of risks associated with crop management options. The charts produced provide conversation pieces for advisers to use with their farmer clients in relation to the significant decisions they face. An example application, detail of the software development process and an initial survey of user needs are presented. We suggest that discussion support software is about moving beyond traditional notions of supply-driven decision support systems. Discussion support software is largely demand-driven and can compliment participatory action research programs by providing cost-effective general delivery of simulation-aided discussions about relevant management actions. The critical role of farm management advisers and dialogue among key players is highlighted. We argue that the discussion support concept, as exemplified by the software tool Whopper Cropper and the group processes surrounding it, provides an effective means to infuse innovations, like seasonal climate forecasting, into farming practice. Crown Copyright (C) 2002 Published by Elsevier Science Ltd. All rights reserved.

A review on the role of duckweed in nutrient reclamation and as a source of animal feed

The family of lemnacae colloquially known as duckweed contains the world's smallest species of flowering plants (macrophytes). Aquatic and free-floating, their most striking qualities are a capacity for explosive reproduction and an almost complete lack of fibrous material. They are widely used for reducing chemical loading in facultative sewage lagoons, but their greatest potential lies in their ability to produce large quantities of protein rich biomass, suitable for feeding to a wide range of animals, including fish, poultry and cattle. Despite these qualities there are numerous impediments to these plants being incorporated into western farming systems. Large genetically determined variations in growth in response to nutrients and climate, apparent anti-nutritional factors, concerns about sequestration of heavy metals and possible transference of pathogens raise questions about the safety and usefulness of these plants. A clear understanding of how to address and overcome these impediments needs to be developed before duckweed is widely accepted for nutrient reclamation and as a source of animal feed.

New source-material for the socio-economic history of the Hindus of Goa

The Mhamai brothers were the suppliers of daily commodities / stationery to the viceroys / governors of Goa. Since late 18th century their agency house worked in partnership with several other trading houses all over the west coast of India. They also served as brokers for the French East India company in Goa during the critical period of anglo-french wars. The Mhamais were also revenue farmers, particularly customs and tobacco tax farming. I had the privilege of taking their family archives to the Xavier Centre of Historical Research in 1979 and making the history of the family known worldwide.

The measurement by serological means of the impact of the Hong Kong/68 influenza virus on a population

In order to obtain evidence on the size of the impact of the Hong Kong/68 variant of influenza A2 virus on the population of São Paulo, Brazil, serum samples taken in 1967 before this variant appeared and during successive years after it appeared were examined for their antibody content. Haemagglutination-inhibition tests performed on a total of 2726 serum samples from adults showed a sharp decrease in 1969 of the proportion of sera without antibody to the Hong Kong/68 variant and a corresponding mercase in the proportion with high titres. It was concluded that about three-quarters of the adult population became infected at some time after the variant appeared, the majority in the first year of prevalence.

Proportional cancer incidence according to selected sites: comparison between residents in the City of S. Paulo, Brazil: Japanese and Brazilian/Portuguese descent

The percentual distributions of selected sites of cancer cases according to origin, sex and age are compared. Data were obtained from the Registry of Cancer of S. Paulo (School of Public Health of the University of S. Paulo, Brazil). The reference period for inhabitants of Japanese descent was 1969/78 and for those of Brazilian descent, the period was 1969/75. Standardized Proportionate Incidence Ratios (SPIR) with approximate 95% Confidence Intervals (CI) were evaluated using age specific Incidence Ratios of S. Paulo, 1973, as standards. The results agree with findings of previous works on mortality, but show different patterns according to origin. The well known fact that some sub-groups of a population may be different from the overall group is once again brought to the fore. Attention should be drawn to the differences detected for stomach, skin and prostate, in males, and for stomach, skin, cervix and uterus in females.

Novel optical PVC probes for on-site detection/determination of fluoroquinolones in a solid/liquid interface: Application to the determination of Norfloxacin in aquaculture water

A novel optical disposable probe for screening fluoroquinolones in fish farming waters is presented, having Norfloxacin (NFX) as target compound. The colorimetric reaction takes place in the solid/liquid interface consisting of a plasticized PVC layer carrying the colorimetric reagent and the sample solution. NFX solutions dropped on top of this solid-sensory surface provided a colour change from light yellow to dark orange. Several metals were tested as colorimetric reagents and Fe(III) was selected. The main parameters affecting the obtained colour were assessed and optimised in both liquid and solid phases. The corresponding studies were conducted by visible spectrophotometry and digital image acquisition. The three coordinates of the HSL model system of the collected image (Hue, Saturation and Lightness) were obtained by simple image management (enabled in any computer). The analytical response of the optimised solid-state optical probe against concentration was tested for several mathematical transformations of the colour coordinates. Linear behaviour was observed for logarithm NFX concentration against Hue+Lightness. Under this condition, the sensor exhibited a limit of detection below 50 μM (corresponding to about 16 mg/mL). Visual inspection also enabled semi-quantitative information. The selectivity was ensured against drugs from other chemical groups than fluoroquinolones. Finally, similar procedure was used to prepare an array of sensors for NFX, consisting on different metal species. Cu(II), Mn(II) and aluminon were selected for this purpose. The sensor array was used to detect NFX in aquaculture water, without any prior sample manipulation.

Solid contact PVC membrane electrodes based on neutral or charged carriers for the selective reading of anionic sulfamethoxazole and their application to the analysis of aquaculture water

Sulfamethoxazole (SMX) is among the antibiotics employed in aquaculture for prophylactic and therapeutic reasons. Environmental and food spread may be prevented by controlling its levels in several stages of fish farming. The present work proposes for this purpose new SMX selective electrodes for the potentiometric determination of this sulphonamide in water. The selective membranes were made of polyvinyl chloride (PVC) with tetraphenylporphyrin manganese (III) chloride or cyclodextrin-based acting as ionophores. 2-nitrophenyl octyl ether was employed as plasticizer and tetraoctylammonium, dimethyldioctadecylammonium bromide or potassium tetrakis (4-chlorophenyl) borate was used as anionic or cationic additive. The best analytical performance was reported for ISEs of tetraphenylporphyrin manganese (III) chloride with 50% mol of potassium tetrakis (4-chlorophenyl) borate compared to ionophore. Nersntian behaviour was observed from 4.0 × 10−5 to 1.0 × 10−2 mol/L (10.0 to 2500 µg/mL), and the limit of detection was 1.2 × 10−5 mol/L (3.0 µg/mL). In general, the electrodes displayed steady potentials in the pH range of 6 to 9. Emf equilibrium was reached before 15 s in all concentration levels. The electrodes revealed good discriminating ability in environmental samples. The analytical application to contaminated waters showed recoveries from 96 to 106%.