142 resultados para Africa, East


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The bastard grunt (Pomadasys incisus) is one of the most abundant coastal demersal fishes inhabiting the Canary Islands. Age and growth were studied from samples collected between October 2000 and September 2001. Growth analysis revealed that this species is a fast growing and moderately short-lived species (ages up to seven years recorded). Length-at-age was described by the von Bertalanffy growth model (L∞=309.58 mm; k=0.220/year; t0=–1.865 year), the Schnute growth model (y1=126.66 mm; y2=293.50 mm; a=–0.426; b= 5.963), and the seasonalized von Bertalanffy growth model (L∞=309.93 mm; k=0.218/ year; t0= –1.896 year; C=0.555; ts=0.652). Individuals grow quickly in their first year, attaining approximately 60% of their maximum length; after the first year, their growth rate drops rapidly as energy is probably diverted to reproduction. The parameters of the von Bertalanffy weight growth curve were W∞=788.22 mm; k=0.1567/year; t0= –1.984 year. Fish total length and otolith radius were closely correlated, r2=0.912. A power relationship was estimated between the total length and the otolith radius (a=49.93; ν=0.851). A year’s growth was represented by an opaque and hyaline (translucent) zone—an annulus. Backcalculated lengths were similar to those predicted by the growth models. Growth parameters estimated from the backcalculated sizes at age were L∞=315.23 mm; k=0.217/year; and t0= –1.73 year.

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Age, size, abundance, and birthdate distributions were compared for larval Atlantic menhaden (Brevoortia tyrannus) collected weekly during their estuarine recruitment seasons in 1989–90, 1990–91, and 1992–93 in lower estuaries near Beaufort, North Carolina, and Tuckerton, New Jersey, to determine the source of these larvae. Larval recruitment in New Jersey extended for 9 months beginning in October but was discontinuous and was punctuated by periods of no catch that were associated with low water temperatures. In North Carolina, recruitment was continuous for 5–6 months beginning in November. Total yearly larval density in North Carolina was higher (15–39×) than in New Jersey for each of the 3 years. Larvae collected in North Carolina generally grew faster than larvae collected in New Jersey and were, on average, older and larger. Birthdate distributions (back-calculated from sagittal otolith ages) overlapped between sites and included many larvae that were spawned in winter. Early spawned (through October) larvae caught in the New Jersey estuary were probably spawned off New Jersey. Larvae spawned later (November–April) and collected in the same estuary were probably from south of Cape Hatteras because only there are winter water temperatures warm enough (≥16°C) to allow spawning and larval development. The percentage contribution of these late-spawned larvae from south of Cape Hatteras were an important, but variable fraction (10% in 1992–93 to 87% in 1989–90) of the total number of larvae recruited to this New Jersey estuary. Thus, this study provides evidence that some B. tyrannus spawned south of Cape Hatteras may reach New Jersey estuarine nurseries.

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Four species of Gracilaria are investigated for their free amino-acid contents, as well as amino-acid constituents in the proteins and the peptides, using quantitative paper chromatographic technique. Amino-acid constituents of different species of Gracilaria differ only in amount, while free amino-acids and the amino-acids in the peptides vary both in quality and quantity. A number of amino-acids recorded as protein constituents have even escaped detection in the peptides, while in the free state they occur either in all the species or in some only except homocystine. Moreover, some amino-acids occur exclusively in the free state.

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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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Besides the formal publications held in the library (books, annual reports. Journals and reprints) a considerable quantity of unpublished Information on subjects relevant to freshwater fisheries in East Africa is held on various departmental files, etc.in Jinja. This material is extremely valuable: firstly because it is usually of immediate reference to current research work at EAFFRO, and secondly because it usually exists only as original material: no other copies are available elsewhere.

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The Annual report covers Research work of the Organization carried out during the period 1975. Its explains the following research work: Haplochromis Studies, Electrophoresis,The Ecology of Haplochromis in the northern waters of Lake Victoria Limnology, Aquatic Pollution and Biochemical Studies The Biology of Synodontis in Lake Victoria Riverine Fisheries, Inshore Fishery of the Kenyan-Waters of Lake Victoria Biostatistics, the Inshore Fisheries of the Western part of Lake Victoria, The Offshore Fisheries of Kenyan Waters of Lake Victoria Lake Mobutu Sese Seko: Stock Assessment and Ecological Studies Fishery Economics, The Biology of Bagrus docmac in Lake Victoria Fishery Resource Surveys of Lake Wamala and Kijanebalola

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There was very little previous information to use as a basis for work on Lakes Edward and George, but fortunately the region had been mapped in some detail by the Uganda-Congo Boundary Commission of 1906-08. This map served as a satisfactory foundation, but the western Congo shoreline of Lake Edward was inserted only by a dotted line, and a number of inaccuracies, particularly with regard to the islands and littoral of L. George, came to light during our survey.

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Very few accounts of African potamonids refer to natural colouration, and the author cannot recall any describing colour patterns. The generally undistinguished appearance of these crabs is well illustrated by Rathbun (1921) on the Congo Brachyura which includes collector's notes on a number of potamonid species. This article is based on remarks extracted from a communication sent to Dr. C. H. Fernando in connection with the article "Colour patterns in Ceylonese freshwater crabs (Patomonidae)", Bulletin of the Fisheries Research Station, Ceylon, v. 21.1(1970), pp. 1-4.

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The fishing industry on Lake Victoria continued to provide a wide spectrum of activities to a variety of people principally the fishermen and the fish mongers, boat builders,fishnets and associated equipment manufacturer transporters on land and water and finally the consumers of the end product the fish. Though there were such varied activities in the industry the year under review, as in previous other recent years, was difficult one being, characterized by continued shortages of fishing gear and accessories, spare parts for the outboard engines, timber for boat building, nails, paints and generally high prices of those items when ever found. Thus this total sum the activities of the fishing industry on Lake victoria was rather slack as compared to those of precious year.

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The execution of this survey was decided upon by Swedevelop in agreement with the Sri Lanka Fisheries Corporation and was a part of the investigations and studies for a fishery project at Trincomalee which was carried out by Scandia Consult. The main purpose was to investigate the following aspects: bottom conditions, especially prawn trawling conditions; size of the potential prawn trawling catches; size and quality of the potential fish trawling catches; suitable sizes and types of boats and trawling gear; duration of trawl fishing season.

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The present work is now concentrated mainly on the Tilapia fishery. As a result of past experience it is easier to direct efforts in a way likely to give useful results. Work on the Tilapia is now beyond the purely exploratory stage and these fishing experiments are being carried but in areas which are known to contain large numbers of Tilapia. Nets of different mesh size are being used in order to catch all stages of these fish. These nets are being fished at the surface and at the bottom, close to the shore and further out. The data collected should provide more precise information regarding the periodic migration, both vertical and horizontal, of these fish, a better understanding of their life history and breeding habits, and indicate' the potential possibilities of this fishery. These data should explain the variation in numbers of fish caught by Africans during different months of the year; they should also make it possible to determine more exactly the best type of net for use in this particular fishery.

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If recent estimates are accurate the world’s human population can be expected to double in the next thirty years. The rate of growth will likely be even greater in many African nations, yet food supplies in these countries especially of essential animal proteins, are even not; inadequate Clearly increased production of food for domestic consumption must become a high- priority development goal. The inland fisheries of Africa will play an increasingly important role in augmenting protein supplies. In 1970, production of the inland fisheries was already-about 1.4 million metric tons, and had increased some 71 per cent in the previous six years. With further development and more affective fishery management a two-fold increase 1n output over the present level can reasonably be expected. Effective management of the fisheries at optimum exploitation levels end development of under utilized fish resources will neccessite major improvement in the stastistical systems employed to produce information on the fish stocks and fisheries. More reliable and detailed information on the catch, effort and other important aspect of the fishing enterprises will be required.

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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.

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The Annual report covers research carried out during the reporting period 1953 and contains the following Hydrology , Algology , Swamps, Snails and snail-eating Haplochromis, Tilapia Haplochromis, Mormyrus, Protopterus , Fish Physiology and list of Publications by members of E.A.F.R.O.