Browsing AfReMaS by Publication date
Now showing items 1-20 of 433
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Analyse de l'état des stocks d'albacore (Thunnus albacares) et de listao (Katsuwonus pelamis) de l'Atlantique au 30 septembre 1980L'article analyse l'état des stocks d'albacore et de listao d'après les informations les plus récents disponibles. Le modéle de production géréralisé est employé en utilisant des données améliorées opue FISM. L'analyse conclue que le stock d'albacore est fortement exploité à un niveau proche de ou légérement supérieure à la prise anuuelle équilibrée.. La production par par recrue de la pêcherie est probablement à un niveau élevé du fait de l'importance captures de gros albacores réalisés par les senneurs et les palangriers. Celle-ci pourrait probablement être améliorée en réduisant les prises de petits albacores hors taille qui demeurent très importantes, tant chez les senneurs que chez les canneurs. Le même modéle appliqué au stock de listao n'a pas permis d'aboutir à des estimations fiables du fait probablement de la grande variabilité des pue et de leur tendance peu nette. Le niveau d'exploitation du ou des stocks de listao et les perspectives de développement de la pêcherie restent en fait une inconnue que l'année internationale du listao contribuera sans doute à lever. This paper analyses the status of yellowfin and skipjack stocks in the Atlantic ocean, using the most recent available informations. Generalised production model has been used, with improved opue statistics of FISM purse seiner fleet. This analyse indicates the present fisheries are exploiting the yellowfin at a level near or above the MSY. The yield per recruit of yellowfin fisheries sems to be quite good, due to the high mean weight of the purse seiners and of the long-line catches. This yield per recruit could still be sligthly increased if catches of small yellowfin, which are still import & in baitbost and purse seiner landings, could be reduced. The same production model applied to skipjack stock does not provides reliable estimates of the MSY. This is probably due to the wide fluctuation of opue which does not show a clear trands, as for yellowfin. The real exploitation level of skipjack stock (s) and the potential catches of atlantic skipjack remains more or lesse completely unknow. The results that will be obtained from ISYP will probably help to solve that problem
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Species composition, distribution and resource pontentials fisheries recorded in bottom trowling betweem 50 and 200M depth off Nigerian the Coast.15 trawl hauls in the 50-200m-depth zone of the Nigerian continental shelf yielded 8092 fishes from 38 families comprising 48 species. Dentex angolensis, Dentex congoensis, priacanthus arenatus and Ariomma bondi were identified as the dominant species. Their resource potential in the area should be further investigated
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Sampling the catch of fishing trawlersThis paper discusses the sample the sample design and estimation method for sampling the commercial catches of fishing trawlers. The result of the application of the design to Nigerian Fishing Trawlers in 1981 is presented. The conclusion that Nigerian Trawlers and not catching undersized fish as at 1981 is valid only on the assumption that there is no dumping of undersized fish at sea.
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Studies on the nutrition of brackish water catfish - Chrysichthys nigrodigitatusThe nutritional effects of the complete or partial replacement of fishmeal by Soyabean meal in the diets of catfish were investigated. Four diets A, B, C, and D in which 34% of fish meal was replaced weight by weight with 0%, 10%, 20% and 34% of Soya-bean meal respectively were fed to four groups of brackish water catfish for six weeks. Results showed that although the digestibilities of proteins were almost equal in all the four groups, the groups fed diet D in which 100% of the fishmeal had been replaced by Soyabean had the least growth as compared to A, B and C. Nevertheless, the group fed diet D (with the least growth) had an economy of gain twice that of the group fed diet A. The liver and heart indices and the proximate compositions of the muscle were not affected by dietary treatments.
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Studies on the nutrition of brackish water catfish - Chrysichthys nigrodigitatusFour groups of brackish water catfish were fed four diets: N. F. (NIOMR formula 1 feed). A. B. and C. for seven weeks. Feeds N.F., A., B. and C. contained 1.21% fish oil + 5.59% vegetable oil; 1.21% fish oil + 7.39% vegetable oil; 1.21% fish oil + 9.09% vegetable oil; 1.21% fish oil +10.89% vegetable oil respectively. The total amounts of vegetable oil in A., B. and C. included the supplementation of the residual oil in the ingredients with 2%, 4% and 6% respectively with ordinary cooking mixed vegetable oil. Results of feeding trial showed that growth was best in the group led diets containing 10.89% vegetable oil and least in those containing 9.09% vegetable oil. There seemed to have been a positive correlation between growth rate and hepatic phospholipids, cholesterol, triglycerides and free fatty acids.
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Etude du recrutement en civelles ( Anguilla Anguilla L. 1758 ) dans l' estuaire du Sebou au cours de la saison de pêche 1980-1981Le recrutement en civelles dans l'estuaire du Sebou (Côte atlantique marocaine)est étudié au cours de la saison de pêche de 1980-1981.Le phénomène s'observe d'octobre à juillet.Les remontées s'effectuent par bancs successifs constitués d'individus de plus en plus petits, de décembre à fin avril.Une stabulation estivale est notée à partir de mai.
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Edible crabs of KenyaThis is a short paper on the edible crabs of Kenya especially Scylla serrata , their present state of exploitation, distribution, abundance and biology. Preliminary investigations have shown that the crab resources are under-exploited. Research is therefore needed into the available stocks, methods of harvesting, processing, marketing and their biologies.
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The autecology of the edible oyster Crassostrea cucullata Born, 1778: size related vertical distribution at Mkomani, MombasaThe littoral oyster Crassostrea cucullata occurs between 1.05-3.35 m above chart datum with the highest density occuring between 1.85-2.75m. Its distribution is size-related as demonstrated by computation of correlation coefficients (r) and regression equations. The shell lengths (i.e. maximum linear dimension) decreases in an upshore direction. The analysis show high r-values which are significant at P<0.001. The elevation and density related effects on the shell lengths of the oysters are discussed.
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Planktonic copepods from coastal and inshore waters of Tudor Creek, MombasaFifty two free swimming planktonic copepod species were identified from the samples collected from three stations in Tudor Creek, Kenya. This appears to be the first systematic account of copepods reported from the coastal and inshore waters of Kenya.
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The food of some neritid prosobranch molluscs found at Mkomani Mombasa, KenyaThe findings are presented of a study conducted at Mkomani, Mombasa, investigating the Nerita species and their feeding habits. Algal food items found in the molluskan stomachs are listed. Nerita is believed to be a herbivorous gastropod feeding upon the algae off rocky shores.
