66 research outputs found

    An assessment of the recreational fishery in the St Lucia estuarine system, KwaZulu-Natal, South Africa

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    St Lucia is one of the largest estuarine systems in Africa, and attracts thousands of anglers each year. Catch card data from the National Marine Linefish System for the years 1986–1999 were analysed to determine catch composition, catch per unit effort (cpue) and seasonality of catches by recreational anglers. Because not all anglers completed catch cards, estimates of total catch were made using additional data on the number of private boat outings, the number of boat trailers at boat slipways and the number of boats recorded entering the campsite gates during 1992 and 1993. In all, 27 fish families, constituting 55 species, were recorded by recreational anglers. Dusky kob Argyrosomus japonicus, spotted grunter Pomadasys commersonnii, perch Acanthopagrus berda, Natal stumpnose Rhabdosargus sarba, springer Elops machnata and mini-kob Johnius dorsalis were the most prominent species caught in terms of numbers and mass. Catch rates expressed numerically (fish angler-1 h-1) peaked during the summer and early winter. However, in terms of mass, catch rates peaked during late winter and spring, when there were increased landings of large dusky kob. Fluctuations in cpue were linked to salinity and estuary mouth conditions (i.e. mouth closure). Despite annual fluctuations in cpue, regression analysis revealed an overall downward trend for the dominant species (dusky kob and spotted grunter) and a gradual increase for stumpnose, perch and springer, but with the exception of stumpnose, these trends were not significant. Socio-economic aspects of the fishery were also investigated by conducting an independent boat-angler survey. The value of the recreational fishery, in terms of accommodation and direct angler expenditure, was estimated to be in the region of R9 million during 1992. Angler attitudes towards fishing regulations were positive and anglers generally had a good knowledge of the regulations for target species. Based on this assessment, a number of suggestions are made regarding the future management of the recreational fishery at St Lucia.Keywords: catch and effort, management, recreational angling, socio-economics, St Lucia estuarine systemAfrican Journal of Marine Science 2002, 24: 263–27

    A survey of the South African shore-angling fishery

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    Roving creel surveys and aerial surveys of shore-angling were undertaken as part of a national investigation into linefishing in South Africa. Shore patrols utilized a random stratified sampling procedure to collect catchand-effort data, and a questionnaire provided information on fishing effort, angler demographics, economics and attitudes towards current regulations. A total of 1 677 patrols, covering 19 616 km, was conducted betweenApril 1994 and February 1996, during which period 9 523 anglers had their catches checked and 4 490 were interviewed. A further 16 497 km were covered by aerial surveys, when 22 609 anglers were counted. Fromthe aerial surveys, angler densities were highest on the KwaZulu-Natal coast (4.65 anglers.km–1), followed by the Southern Cape coast (2.29 anglers.km–1), the Eastern Cape coast (0.36 anglers.km–1) and the WestCoast (0.12 anglers.km–1). Catch rates varied from 1.5 kg.angler –1.day–1 on the Southern Cape coast to 0.45 kg.angler–1.day–1 on the KwaZulu-Natal coast. Total effort was estimated at 3.2×106 angler days.year–1 and the total catch was estimated at 4.5×106 fish.year–1 or 3 000 tons.year–1. Targeted species varied regionally, with elf Pomatomus saltatrix (29%) being the most sought after species on the KwaZulu-Natal coast, kob Argyrosomus japonicus (18%) on the Eastern Cape coast and galjoen Dichistius capensis on the Southern Cape coast (30%) and along the West Coast (50%). The catch composition by mass was dominated byP. saltatrix on the KwaZulu-Natal coast (29%), the Eastern Cape coast (26%), and on the Southern Cape coast (56%) and by white stumpnose Rhabdosargus globiceps (40%) on the West Coast. Although anglersgenerally supported the regulations currently governing the linefishery, the questionnaire results showed that knowledge and compliance of them was poor. A low level of law enforcement was found, except for inKwaZulu-Natal. Management of the linefishery is discussed in relation to the findings of this study

    An economic valuation of the South African linefishery

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    Economic data collected during 1995 and 1996 in a national survey of shore-anglers and skiboat fishermen is used to provide an economic assessment of aspects of recreational, subsistence and commercial linefishing on the South African coastline. Results show that more than 90% of shore-anglers have incomes which lie in the highest two quintiles of the distribution of incomes, and tha

    Long-term catch and effort trends in Eastern Cape Angling Week competitions

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    Recreational shore-based angling is one of the most popular sport and outdoor activity pastimes in South Africa with an estimated 412 000 fishers (McGrath et al. 1997). It is a form of linefishing where fish are caught using a hook and line and comprises a social as well as a more formal organized competitive sector (van der Elst 1989). Similar to other components of the linefishery, which include the subsistence as well as boat-based commercial sectors, excessive shore-fishing effort along the Eastern Cape has resulted not only in declining catches (Bennett 1991, Griffiths 1997, Brouwer and Buxton 2002, Pradervand and Govender 2003) but also changes in the species composition of catches (Bennett et al. 1994, Brouwer et al. 1997, Attwood and Farquhar 1999). Stock assessments indicate that many important linefish species are severely overexploited (Griffiths 1997, Hutchings 2000, Mann 2000) and that continued fishing pressure threatens endemic linefish populations. In 1996, shore-anglers alone were responsible for an annual catch of approximately 4.5 million fish, weighing around 3 000 tonnes (Brouwer et al. 1997)

    Continuous Regional Arterial Infusion with Fluorouracil and Octreotide Attenuates Severe Acute Pancreatitis in a Canine Model

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    Aim: To investigate the therapeutic effects of fluorouracil (5-Fu) and octreotide (Oct) continuous regional arterial infusion (CRAI,) alone or in combination, was administered in a canine model of severe acute pancreatitis (SAP). Materials and Methods: The animals were divided into five groups; group A (Sham), group B (SAP), group C (SAP and 5-Fu), group D (SAP and Oct), and group E (SAP and 5-Fu + Oct). Levels of amylase, alpha-tumor necrosis factor (TNF-alpha), blood urea nitrogen (BUN), creatinine, thromboxane B2 and 6-keto-prostaglandin F1 alpha were measured both before and after the induction of SAP. Pathologic examination of the pancreas and kidneys was performed after termination of the study. Results: Pathologic changes noted in the pancreas in SAP significantly improved following CRAI with either single or combined administration of 5-Fu and Oct, where combination therapy demonstrated the lowest injury score. All treatment groups had significantly lower levels of serum TNF-alpha and amylase activity (P<0.05), though only groups D and E had a lower BUN level as compared to group B. The plasma thromboxane B-2 level increased in SAP, but the ratio of thromboxane B-2/6-keto-prostaglandin F-1 alpha decreased in the treatment groups, with the combination therapy (group E) demonstrating the lowest ratio as compared to the other 3 experimental groups (P<0.05). Conclusions: The findings in the present study demonstrate an attenuation of SAP in a canine model following CRAI administration with 5-Fu or Oct, alone or in combination

    Pan-cancer analysis of whole genomes

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    Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe

    Review of the state of Marine protected areas in South Africa

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    The use of marine protected areas (MPAs) in South Africa should be revised in the light of growing problems related to the over-use of marine resources. No consistent policy has been applied to the establishment andmanagement of MPAs. Existing MPAs include marine reserves, restricted areas, single-species restricted areas, National Parks, estuarine protected areas, trawling reserves and offshore islands, declared under a varietyof legislation. Marine reserves and restricted areas have been declared under the Sea Fishery Act, but are managed by provincial authorities. The provincial authorities in the Northern, Western and Eastern Capelack the necessary resources for marine management. By contrast, the KwaZulu-Natal Nature Conservation Service and the National Parks Board are adequately staffed and equipped to provide all the necessary managerial functions in their MPAs. The effectiveness of most MPAs is not assessed and they do not have clearly stated objectives or management plans. MPA boundaries are inappropriately demarcated at sea. Two marinebiogeographic zones and two marine habitat types are poorly represented in MPAs. Ecologically and economically important species are well represented in MPAs, but effective protection is less satisfactory. SomeMPAs are playing an important role in fisheries management. Community resource-use programmes in KwaZulu-Natal have helped to control poaching to some extent. It is recommended that South Africa establisha MPA Programme. MPA objectives should be clearly stated and communicated to the public through education programmes. Research, monitoring and enforcement in MPAs should be improved

    An assessment of participation, catch and effort in the KwaZulu-Natal shore-based marine linefishery, with comments on management effectiveness

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    The primary purpose of this study was to evaluate the effectiveness of current management of the KwaZulu-Natal (KZN) shore-based marine linefishery. Methods used included a stratified-random creel survey and an associated questionnaire survey. The study was undertaken between February 2009 and January 2010. Total participation ranged between 41 283 and 68 087 shore-anglers. Results show that there has been little change in participation in the KZN shore-fishery since 1994–1996. In contrast, total angler effort (779 382–843 702 angler-days y–1) has decreased substantially over the past 13 years. Overall catch per unit effort (CPUE) for the KZN shore-linefishery amounted to 0.18 ± 0.3 fish angler–1 h–1 or 0.07 ± 0.13 kg angler–1 h–1. In all, 84 fish species, belonging to 39 families, were recorded in catches of shore-anglers during the study period. Only five species accounted for 75% of the catch recorded along the coast (Sarpa salpa 34.8%, Pomatomus saltatrix 14.7%, Diplodus capensis 14.5%,  Pomadasys olivaceum 6.5% and Rhabdosargus holubi 4.9%). The total annual catch for the KZN shore-linefishery was estimated between 249.2 and 276.7 t y–1 (or 636 589–706 995 fish y–1). Analysis of overall CPUE, catch composition and total  catch in the shore-based linefishery of KZN suggested that it is currently in a relatively stable condition and that little change has occurred over the past 13 years. However, comparisons of species-specific CPUE values from this study with recent literature suggest that some species (e.g. Argyrosomus japonicus) are severely overexploited.  Over the past few decades there seems to have been a gradual transition in landings from long-lived, high trophiclevel, piscivorous fish (e.g. A. japonicus) to more short-lived, low trophic-level species (e.g. S. salpa). The results therefore suggest that present exploitation levels may not be sustainable for certain slow-growing, long-lived fish species. Current management regulations appear to have limited effectiveness based on poor angler compliance and knowledge of the regulations. In this regard, it is important to consider alternate management measures that may offer more effective protection to fish and at the same time be more easily understood by all anglers in the linefishery. Recommendations for improved management and the importance of the establishment of an effective MPA network are briefly discussed.Keywords: catch composition, catch per unit effort, fishing effort, fisher participation, linefish, questionnaire survey, roving-creel survey, shore-anglingAfrican Journal of Marine Science 2012, 34(4): 479–49

    An assessment of participation, catch and effort in the offshore boat-based linefishery in KwaZulu-Natal, South Africa

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    This study evaluates trends in participation, catch and effort in the KwaZulu-Natal offshore boat-based linefishery. Methods used included a random access-point survey and an associated questionnaire survey. The study was undertaken between February 2009 and April 2010. Total participation in all sectors (recreational, charter and commercial) ranged between 18 217 and 20 546 boat-fishers and between 2 582 and 3 326 boats. Similarly, total fisher effort in the offshore linefishery was estimated at 39 664 boat-outings y–1. The commercial boat sector had the highest catch per unit effort (CPUE) both numerically (307.4 fish outing–1) and by weight (235.6 kg outing–1). In contrasting, the recreational boat sector had the lowest CPUE both numerically (8.6 fish outing–1) and by weight (15.0 kg outing–1). In total, 86 fish species, belonging to 27 families, were recorded in catches of boat-fishers (all sectors) during the study period. Catch composition was similar with Chrysoblephus puniceus, Chrysoblephus anglicus and Lethrinus nebulosus being represented in the top five species of all three fishery sectors. Analysis of overall CPUE, catch composition and total catch of the offshore boat-based linefishery in KZN suggested that the fishery is currently in a relatively stable condition and that little change has occurred over the past 13 years. However, specific CPUE values from this study together with those reported in the literature suggest that some species may be severely overexploited. It is recommended that stock assessments of the priority species should be conducted in the near future and steps should be taken to encourage rebuilding of overexploited species. This must include urgent regulation of the burgeoning charter boat-fishery as well as increased attempts to establish more marine protected areas.Keywords: access-point surveys, boat-fishing, catch composition, catch per unit effort (CPUE), charter, commercial, fishing effort, fisher participation, recreational, total catchAfrican Journal of Marine Science 2013, 35(1): 79–9
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