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CL de Moor SJ Johnston A Brandão RA Rademeyer JP Glazer LB Furman 《African Journal of Marine Science》2015,37(3):285-311
The waters off South Africa's coastline boast a rich mix of commercially fished species. Quantitative assessments of these marine resources have developed from simple methods first applied in the 1970s, to models that encompass a wide range of methodologies. The more valuable resources have undergone regular assessments in recent decades, with frequencies closely related to the management approach employed for each fishery. Many of these assessments form the operating models used to simulation-test candidate management procedures. This paper provides a comprehensive review of the assessments of 11 of the most important fisheries resources in South Africa. Some assessments use simple biomass dynamics models, whereas others are a hybrid of age- and length-based models, each designed to model the specific characteristics of the resource and fishery concerned. Many of the assessments have been disaggregated by species/stock and/or area as related multispecies/stock/ distribution hypotheses have arisen. This paper explores the similarities and differences in the data available and the methods applied. The review indicates that, whereas the status of three of these resources cannot be estimated reliably at present, the status of six resources is considered to be reasonable to good, whereas that of abalone Haliotis midae and West Coast rock lobster Jasus lalandii remains poor. 相似文献
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《African Journal of Marine Science》2013,35(1):17-25
A roving creel survey of recreational shore-anglers in Namibia was used to determine catch and effort of line-fishing. A stratified sample of 240 anglers was surveyed to determine expenditures. Results showed that, between October 1996 and September 1997, some 8 800 anglers spent around 173 000 days angling and had direct expenditures of N$29.7 million. In all, 93% of angling took place in the West Coast Recreational Area. Some 44% of anglers were foreign visitors who contributed 55% of the expenditures. Value added to gross national income within the shore-angling fishery was N$14 million, equivalent to 3.6% of the value of the whole fisheries sector. The expenditures ultimately amounted (through a multiplier) to a gross national income of N$3 069 per angler, or N$27 million in aggregate. These amounts could be sustainable if policies to reduce fish mortality without affecting angler numbers are implemented. 相似文献
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