31 resultados para University of South Africa.

em Aquatic Commons


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This study documents validation of vertebral band-pair formation in spotted gully shark (Triakis megalopterus) with the use of fluorochrome injection and tagging of captive and wild sharks over a 21-year period. Growth and mortality rates of T. megalopterus were also estimated and a demographic analysis of the species was conducted. Of the 23 OTC (oxytetracycline) -marked vertebrae examined (12 from captive and 11 from wild sharks), seven vertebrae (three from captive and four from wild sharks) exhibited chelation of the OTC and fluoresced under ultraviolet light. It was concluded that a single opaque and translucent band pair was deposited annually up to at least 25 years of age, the maximum age recorded. Reader precision was assessed by using an index of average percent error calculated at 5%. No significant differences were found between male and female growth patterns (P>0.05), and von Bertalanffy growth model parameters for combined sexes were estimated to be L∞=1711.07 mm TL, k=0.11/yr and t0=–2.43 yr (n=86). Natural mortality was estimated at 0.17/yr. Age at maturity was estimated at 11 years for males and 15 years for females. Results of the demographic analysis showed that the population, in the absence of fishing mortality, was stable and not significantly different from zero and particularly sensitive to overfishing. At the current age at first capture and natural mortality rate, the fishing mortality rate required to result in negative population growth was low at F>0.004/ yr. Elasticity analysis revealed that juvenile survival was the principal factor in explaining variability in population growth rate.

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South Africa's marine resources are essentially fully exploited and in some cases over exploited. The Government of National Unity has embarked on the ambitious Reconstruction and Development Programme (RDP) to: meet the basic needs; develop the country's human resources; build economy; and democratize the state and society. Although fisheries can only be expected to play a minor role in contributing to RDP, the Programme have a role to play in managing South Africa's living marine resources. The role of RDP in fisheries management is presented together with fisheries management approaches to help achieve the aims of the RDP.

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Sri Lanka is a comparatively small island (65.584 km²) within the equatorial belt of calms. There are only slight seasonal variations in temperature, air humidity and day length. A description is given of the amphibian and reptile material brought back from the Austrian Indo-Pacific expedition, 1970-71. Some notes on the habitat of the animals are included.

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Integral to achieving the SSF Guidelines goal of targeting the most vulnerable and marginalized persons and eliminating discrimination is the need to have adequate understanding of the power relations and intersectionalities that shape access to and control over marine and other resources according to gender, age, race, ethnicity, labour and migratory status, disability, geographic location and other characteristics relevant in each national contexts. This monograph identifies and explores the key social relations and dynamics in the SSF fisheries sector in South Africa impacting the implementation of the SSF Guidelines. The monograph will be useful for researchers, scientists, fishworker organizations, environmentalists and anyone interested in the protection of marine biodiversity and the promotion of sustainable fisheries management.

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The diet of marine animals is usually determined by stomach content analysis. Although partially digested prey fragments can often be identified to species level, it is difficult to estimate the original mass of the prey organism. This information, however, is essential for calculating both the total food intake as well as the relative contribution of each prey item. In this study we present regression equations that can be used to estimate the original mass of 18 common South African crustaceans from various indigestible fragments such as the carapace (length and width), chelae (length and width of left and right dactylus) and eye (length and width).

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The Austrian-Ceylonese hydrobiological mission of 1970 investigated and made collections from 36 flowing water systems (brooks, torrents, rivers); of these, 34 water systems were in the mountains regions of south-west and south-east of Sri Lanka. In the crystalline mountain region, the water systems are extremely poor in electrolytes, very soft and slightly acid; these torrential streams have strong falls, high flow velocities and boulder bottoms. The water temperatures increase from the sources and brooks at 2,000 m altitude to the mouths from 15°C to 28°C. The density of animal population (macro and meso-fauna) increases from the river bank regions (and pools) towards the sections with strong current and reaches on the rocks in the cascades a density of 500 to appr. 750 individuals/1/16m².

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The morphology, climate, geology and geochemistry of Sri Lanka is briefly described. The separation into a wet zone (the south-west and greater part of the central highland) and a dry zone with two very dry parts in the south-east and in the north-west, is obvious and has great influence on the hydrochemistry of the island. Geology is very homogenous (Precambrian crystalline series) and some Jurassic and Miocene limestones (only in the north).

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In the study are described five species of watermites, collected by the Austrian-Ceylonese hydrobiological mission 1970 in torrents of the highlands of south-west Sri Lanka. The species are: Torrenticola (Monatractides) pusta Cook, 1967, T.(M.) Oxystoma hamata (Lundbald, 1941), T.(M.) ceylonensis nov. spec., Atractides schwoerbeli Lundbald, 1969 and Arrenurus (Micruracarus) madaraszi Daday, 1898.

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The first comprehensive study on the freshwater Caridea of Sri Lanka was by Arudpragrasm and Costa in 1961. Although it was the intention of these authors to continue this study no opportunity was available to them. The present faunal survey however has afforded the present writer to make a detailed study of the distribution of these shrimps especially in the mountain streams of the south-west of Sri Lanka. Two species and two sub-species of Caridina, one species of Atya and four species of Macrobrachium were collected by the hydrobiological mission from the hill streams of Sri Lanka.

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The collection of Triclads from the Austrian-Ceylonese hydrobiological mission originates from 23 streams in the mountains of the south of Sri Lanka. All collected animals are of the Dugesia gonocephala (Dug.) type. Unfortunately the determinable mature animals were very rare in the samples but it seems certain that all the Triclads, found by the mission, belong to Dugesia nannophallus, described by Ball in 1970 after two individuals from Dunhinda, Badulla (Prov. Uva, Sri Lanka).

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The report deals with the material on freshwater crabs, collected by the Austrian-Ceylonese hydrobiological mission 1970 from the running waters of the mountains in south-west Ceylon. The locality records for Paratelphusa (Oziotelphusa) senex (Fabricius 1798) Paratelphusa (Ceylontelphusa) sorror (Zehntner 1894) and Paratelphusa (Ceylontelphusa) rugosa (Kingsley 1880), are described.

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A total of 378 specimens from 25 collecting localities belonging to 31 different species of fish collected mainly from the rivers of the hilly and mountain regions of the south-western and southern Ceylon have been identified and recorded. Ecological data and water analyses of these collecting localities are given.

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This monograph studies the progress achieved by conservation partners in South Africa on the implementation of the Convention on Biological Diversity (CBD) Programme Element Two components of governance, participation, equity and benefit sharing, from the perspective of small-scale fishing communities. It explores the strategies and mechanisms used by different authorities to create the conditions whereby local communities can benefit from marine protected areas (MPAs), of which South Africa has gazetted 24, highlighting examples of best practice. The monograph will be useful for researchers, scientists, fishworker organizations, environmentalists and anyone interested in the protection of marine biodiversity and the promotion of sustainable fisheries management.