739 resultados para Lake trout fisheries


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Five species of submerged vegetation Lagarosiphon ilicifolius, Najas pectinata, Vallisneria aethiopica, Ceratophyllum demersum and Potamogeton octandrus; 7 species of gastropods Melanoides tuberculata, Bellamya capillata, Biomphalaria pfeifferi, Bullinus tropicus, Cleopatra sp, and Lymnaea natalensis and 4 species of bivalves Corbicula africana, Caelatura mossambicensis, Mutela dubia and Aspatharia wahlbergii are correlated with environmental variables particularly slope and transparency, in Lake Kariba. A stepwise regression analysis further revealed interdependence between (Cleopatra sp., B. pfeifferi, L. natalensis, B. capillata, and V. aethiopica as well as between as between C. mossambicensis and L. ilicifolius and N. pectinata. The dependence of B. pfeifferi, L. natalensis, B. capillata, Cleopatra sp. on V. aethiopica and C. mossambicensis on L. ilicifolius and N. pectinata implies that a change in the biomass of the vegetation species may affect distribution and biomass of the faunal species.

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The water quality in fish cages on Lake Kariba was studied. The Kruskal-Wallis test was used to determine whether the water quality parameters differed significantly among the cage-types (cage-type effect). Secchi disc readings ranged from 2 to 4 metres, while temperature ranged from 23 degree C to 29.5 degree C. The observed conductivity was between 98.7 mu S/cm and 102.3 mu S/cm. The pH was between 6.31 and 7.82. Concentrations of dissolved oxygen varied from 1.55 to 6.47 mg/l, while dissolved oxygen saturation ranged from 22.3% to 83.1%. Within the same month, temperature did not differ significantly among cages. Conductivity, pH, dissolved oxygen concentration and dissolved oxygen saturation differed significantly among the 3 cage-types. Temperature and pH levels in the cages were close to the optimum levels for the culture of cichlids. Sub-optimal levels of dissolved oxygen occurred occasionally in the octagonal cages.

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The bibliography contains some 116 citations, including unpublished reports and manuscripts, regarding Lake Kariba. Most of the reports are from the Zambia/Zimbabwe SADC Fisheries and Lake Kariba Fisheries Research Institute. The citations are listed in alphabetical order according to author.

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The findings are presented of a survey conducted on Lake Kariba in order to update the basic statistics of the inshore fishery from a previous survey conducted in 1993 and also to collect some socioeconomic data regarding the artisanal fishery. The 1998 frame survey provided information on fishers both for the whole fishery and per village and changes in numbers; socio-economic characteristics as well as the number of fishing units and gear are included.

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Fishery statistics for 1979 are presented for: (1) total production; (2) effort; (3) landings and purchases; (4) monthly percentage composition and average weight of each species caught in gill-nets.

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The 1980 statistics of the open-water sardine (Limnothrissa miodon ) fisheries and gill-net fisheries are presented. Summaries of total production and total effort, landings inshore and gill-net fisheries are also presented.

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Two types of fishermen have been identified along the lake shore: contract fishermen and independent fishermen. Independent fishermen move from their fishing grounds to other grounds in search for more fish and also to communal lands for farming during the rains. The fish from Kariba are marketed to a large part of the country creating a very large market potential. Profits accruing to the fishermen are not very attractive and could be the reason for the migratory behaviour of the fishermen. The fishermen population is rural with a characteristic expansive pyramid.

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Phytoplankton counts were made on a monthly basis on water samples, taken from one station in the Sanyati Basin. The results show seasonal fluctuations which are probably nutrient dependant. High phytoplankton numbers occur at times of high nutrient levels as was found with the crustacean zooplankton populations (Marshall 1980). Numbers also decreased with depth down to the thermocline. Below the thermocline there was little or no change in numbers.

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The essential aim of this study was to provide a broad foundation of biological knowledge upon which a programme of mussel utilization and management could be built. Results of the study are presented in three main sections. Part 1 describes the stock of Lake Kariba and Lake McIlwaine; part 2 describes various aspects of the breeding biology of the three species; and part 3 presents the results of morphological, biochemical and age analyses - aspects which are used for initial standing crop and production calculations. The final discussion concludes the thesis with a general examination in ecological terms of the factors which have influenced the development and nature of the mussel faunas of the two lakes under consideration.

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This is the report from the Mersey and Weaver Fisheries Advisory Committee meeting, which was held on the 9th April 1980. The report contains minutes of previous meetings, rod and line licence duties, the future programme for trout fisheries in the Bolton area and Commonbank Lakes. It also includes the report by the area fisheries officer which looks at river conditions and fishing, Hollingworth and Pilot Hatcheries, Worthington Stock Ponds, and stockings carried out by the Authority and Angling Associations. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 26th April 1982. The report contains sections on the minutes of the last meeting and recommendations for these committees, Fishery Improvement Grant and Fishery Equipment Loan Schemes, rod and line fishing licences format, objections to proposed new fishery byelaws, an Economic Evaluation of Salmon Fishing by the Atlantic Salmon Trust, and stocking of the Authority’s Directly-Managed trout fisheries. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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This is the report from the Regional Fisheries Advisory Committee meeting, which was held on the 28th April 1980. The report contains the minutes of the Local Fisheries Advisory Committees, rod and line licence duties, and the development of Public Trout Fisheries. The Fisheries Advisory Committee was part of the Regional Water Authorities, in this case the North West Water Authority. This preceded the Environment Agency which came into existence in 1996.

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Throughout the year the Fisheries Departments of Tanzania and Uganda continued to forward to EAFFRO data on the commercial fisheries of the lake. Regular records of commercial fishing activity In Kenya waters have not been received, appropriate information has been made available on request from the Chief Fisheries Officer. None of the research staff at EAFFRO have been assigned to a detail ed survey of the statistica1 data available, although severa1 research officers have taken the opportunity of analysing the data appropriate to their own research programmes. As recorded in the last Annual Report, an important feature of the UNDP Lake Victoria Fisheries Research Project will be to undertake the relevant statistical surveys essential to the proper.

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Lake Niassa fisheries are artisanal and are carried out by numerous fishing boats using various types of gear and operating from numerous fish landing places scattered along the shoreline. A frame survey was conducted in 1983 to get information on the size and structure of the fisheries in Lake Niassa. The methodology to be applied for a catch assessment survey is explained. The primary objective of the survey is to obtain reliable current estimates, for the Mozambican side of Lake Niassa, of the total quantity of fish harvested by the fishermen at the lake (in terms of live weight in tons). Secondary objectives include the species composition of the catch and the fishing effort involved in obtaining the catch.

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This report covers the period 1st July, 1955, to 30th June, 1956. As printing has been delayed for various reasons, reference should be made to certain important proposals put forward since the 30th June. Just after the close of the year a meeting of the Lake Victoria Fisheries Board was held at Entebbe on 26th July. At this meeting disagreement arose between the representatives of the three East African Governments on the subject of whether or not existing restrictions on fishing in Lake Victoria should be retained. This organization holds strongly to the view that the existing restrictions on fishing should be retained, Kenya holds similar views, but Uganda and Tanganyika were in favour of a proposal to lift these restrictions. This question was discussed a month earlier by the Director with the Colonial Office Fisheries Advisory Committee and they also advised the Lake Victoria Fisheries Board against lifting the restrictions.