1,676 research outputs found

    DYNAMICS OF THE FISHERY FOR GALJOEN DICHISTIUS CAPENSIS, WITH AN ASSESSMENT OF MONITORING METHODS

    Get PDF
    The dynamics of the fishery for galjoen Dichistius capensis were investigated at four sites in South Africa from 1987 to 2000. At three sites, which were protected from fishing, Koppie Alleen, Lekkerwater (both in the De Hoop Marine Protected Area) and Tsitsikamma National Park, fishery-independent surveys were conducted. Data for the Cape Peninsula (the fourth site) were obtained from records kept by a recreational angler. Catch per unit effort (cpue) was highest at De Hoop and lowest at Tsitsikamma. At De Hoop, cpue varied significantly among anglers, months, years and gear type. The mortality rate was greater at the exploited site than at protected sites, where mortality rates were taken as estimates of natural mortality. Tag and recovery data were used to estimate density and catchability. Fishing mortality rates were very high, whether inferred from size distributions or from the product of effort counts and the catchability coefficient. Such high rates can be sustained only through refuges. Variation in fishery parameters among habitats and the high variance in cpue data suggest that an effective monitoring programme will need to be intensive. To provide adequate stock assessments, fisherydependent surveys should be augmented by studies in marine protected areas. Afr. J. mar. Sci. 25: 311–33

    Managing crop tradeoffs: A methodology for comparing the water footprint and nutrient density of crops for food system sustainability

    Get PDF
    The relationship between human nutrition and the use of available resources to feed the planet's growing population demands greater attention from decision makers at all levels of governance. Indicators with dual environmental sustainability and food and nutrition security goals can encourage and measure progress towards a more sustainable food system. This article proposes a methodology that supports the development of an approach to assess the water footprint of nutrient-dense foods [m3/kg]. It provides a clear explanation of the methodology, and the use of water footprint benchmark data and corresponding United States Department of Agriculture (USDA) nutrient composition data to apply the process. The study analyzed data for 17 grains, roots and tubers, 9 pulses, 10 nuts and seeds, 17 vegetables, and 27 fruits. Of these, fruits and vegetables are 85% of the bottom quartile for water footprint (i.e., highly water efficient) and 100% of the top quartile for nutrient-density (i.e., very nutrient dense). Spinach is a clear winner, with a very high nutrient-density and low water footprint. The article proposes that this approach can help to establish broad typologies to guide decision makers in distinguishing between win-win, win-lose, and lose-lose scenarios of natural resource use and nutrition security. This resource, if considered along with contributing social, environmental, and economic factors (e.g., local tastes, available water resources, soil fertility, local economies) can promote a food system that offers a diverse range of nutrient-dense foods more sustainably

    Structural analysis of the GH43 enzyme Xsa43E from Butyrivibrio proteoclasticus

    Get PDF
    The rumen of dairy cattle can be thought of as a large, stable fermentation vat and as such it houses a large and diverse community of microorganisms. The bacterium Butyrivibrio proteoclasticus is a representative of a significant component of this microbial community. It is a xylan-degrading organism whose genome encodes a large number of open reading frames annotated as fibre-degrading enzymes. This suite of enzymes is essential for the organism to utilize the plant material within the rumen as a fuel source, facilitating its survival in this competitive environment. Xsa43E, a GH43 enzyme from B. proteoclasticus, has been structurally and functionally characterized. Here, the structure of selenomethionine-derived Xsa43E determined to 1.3 Å resolution using single-wavelength anomalous diffraction is reported. Xsa43E possesses the characteristic five-bladed β-propeller domain seen in all GH43 enzymes. GH43 enzymes can have a range of functions, and the functional characterization of Xsa43E shows it to be an arabinofuranosidase capable of cleaving arabinose side chains from short segments of xylan. Full functional and structural characterization of xylan-degrading enzymes will aid in creating an enzyme cocktail that can be used to completely degrade plant material into simple sugars. These molecules have a range of applications as starting materials for many industrial processes, including renewable alternatives to fossil fuels

    A step-by-step framework to assess benefits of established temperate marine protected areas

    Get PDF
    Marine protected areas (MPAs) have been advocated as a solution to the challenges of both conservation and modern fishery management, but their application remains controversial, partly because there are only general guidelines for evaluating their effectiveness. We propose a framework to specifically evaluate established MPAs in six steps. We tested the approach by reviewing published research and unpublished information on the Goukamma MPA in the centre of the South African temperate south coast. Information reviewed included effects on the structure of fish populations, catch and abundance indices of fish species, and ecosystem effects. We investigated factors that determine the usefulness of a MPA in fisheries management, including the movement behaviour of adult fishes, larval dispersal and fisher-displacement patterns. We found that differences in the rates of exploitation across the MPA border resulted in differences in abundance, size and condition of the main target species, roman (Chrysoblephus laticeps). The diversity and abundance of non-target fish species, and the composition of the benthic invertebrate community, were affected by the cessation of fishing. The potential for ‘spillover’ of adult roman might be limited to the vicinity of the MPA by their small home range, but there is potential for self-seeding and dispersal of roman eggs and larvae over wider areas. These theoretical considerations were confirmed by an analysis of catch data from before and after MPA implementation. The framework presented here may help to identify and fill gaps in the knowledge of established MPAs along South Africa’s temperate south coast

    The PRINTS database: a fine-grained protein sequence annotation and analysis resource—its status in 2012

    Get PDF
    The PRINTS database, now in its 21st year, houses a collection of diagnostic protein family ‘fingerprints’. Fingerprints are groups of conserved motifs, evident in multiple sequence alignments, whose unique inter-relationships provide distinctive signatures for particular protein families and structural/functional domains. As such, they may be used to assign uncharacterized sequences to known families, and hence to infer tentative functional, structural and/or evolutionary relationships. The February 2012 release (version 42.0) includes 2156 fingerprints, encoding 12 444 individual motifs, covering a range of globular and membrane proteins, modular polypeptides and so on. Here, we report the current status of the database, and introduce a number of recent developments that help both to render a variety of our annotation and analysis tools easier to use and to make them more widely available

    A change of the seaward boundary of Goukamma Marine Protected Area could increase conservation and fishery benefits

    Get PDF
    Goukamma Marine Protected Area (MPA) on the South African temperate South Coast has been shown to be effective in maintaining a spawning stock of roman, Chrysoblephus laticeps (Sparidae). The larval ecology and the oceanographic conditions in the area suggest a good potential for the enhancement of roman stocks outside the reserve through larval dispersal. A high rate of illegal fishing just inside the seaward boundary of the MPA could severely compromise its function.We suggest that a change of the seaward boundary of the reserve to coincide with a latitudinal line could increase its function as a harvest refuge for resident reef fishes such as roman, facilitate voluntary compliance and monitoring and prosecution of illegal fishing without a significant negative impact on the commercial linefishing fleet in the area. Simple adjustments such as the one proposed here could be attempted at a number of South African MPAs as they would be beneficial to achieve fishery and conservation goals alike

    An evaluation of individually delivered secret agent society social skills program for children with high-functioning autism spectrum disorders: A pilot study

    Get PDF
    © The Author(s) 2015. High-functioning children with autism spectrum disorders display social skill deficits that can have a debilitating impact on their daily lives. The Secret Agent Society (SAS) program has been shown to be effective in improving the social skills of these children when delivered in a group setting. This pilot study evaluated whether individually delivered SAS would yield similar outcomes. Three participants were recruited for the 9-week intervention. Measures of social competence were administered at four points: pretest 1, pretest 2, post-intervention, and 6-week follow-up. Participants showed significant improvement in half of the measures assessing social competence. On a third of these measures, two participants demonstrated improvements to within the range of their typically developing peers. Follow-up results suggested that improvements were maintained at 6 weeks' post-intervention. Limitations of this study and directions for future research are discussed

    A change of the seaward boundary of Goukamma Marine Protected Area could increase conservation and fishery benefits

    Get PDF
    Goukamma Marine Protected Area (MPA) on the South African temperate South Coast has been shown to be effective in maintaining a spawning stock of roman, Chrysoblephus laticeps (Sparidae). The larval ecology and the oceanographic conditions in the area suggest a good potential for the enhancement of roman stocks outside the reserve through larval dispersal. A high rate of illegal fishing just inside the seaward boundary of the MPA could severely compromise its function. We suggest that a change of the seaward boundary of the reserve to coincide with a latitudinal line could increase its function as a harvest refuge for resident reef fishes such as roman, facilitate voluntary compliance and monitoring and prosecution of illegal fishing without a significant negative impact on the commercial linefishing fleet in the area. Simple adjustments such as the one proposed here could be attempted at a number of South African MPAs as they would be beneficial to achieve fishery and conservation goals alike

    The emergence of marine recreational drone fishing: regional trends and emerging concerns

    Get PDF
    Online evidence suggests that there has been an increase in interest of using unmanned aerial vehicles or drones during land-based marine recreational fishing. In the absence of reliable monitoring programs, this study used unconventional publicly available online monitoring methodologies to estimate the growing interest, global extent, catch composition and governance of this practice. Results indicated a 357% spike in interest during 2016 primarily in New Zealand, South Africa and Australia. From an ecological perspective, many species targeted by drone fishers are vulnerable to overexploitation, while released fishes may experience heightened stress and mortality. From a social perspective, the ethics of drone fishing are being increasingly questioned by many recreational anglers and we forecast the potential for increased conflict with other beach users. In terms of governance, no resource use legislation specifically directed at recreational drone fishing was found. These findings suggest that drone fishing warrants prioritised research and management consideration.info:eu-repo/semantics/publishedVersio
    corecore