513 resultados para Freshwater fishes.


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This supplement to the “Guide to the freshwater fauna of Ceylon” by A. S. Mendis and C. H. Fernando. Bull Fish. Res. Stn. Ceylon 12, 160 pp. (1962) includes a number of additional records to the fauna and nomenclatural changes designed to bring the names of the Rotifera, and Hydracarina up to date. This latter involves a complete change in naming of Rotifera to keep in line with modern nomenclature synonymizing species where necessary. A major study on the water mites of India by Cook (1067) has necessitated considerable changes in the naming of Ceylonese species. Besides the Rotifera and Hydracarina the Ilemiptera-Heteroptera have received attention as regards the Corixidae and new generic and specific records from published and unpublished material has been included. A major difficulty in studying freshwater animals (for that matter any animals) is the lack of suitable illustrations of local forms. An attempt has been made to fill this gap for the Rotifera and Turbellaria, It is hoped that in future supplements other groups can be similarly dealt with.

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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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Based on our present knowledge a comprehensive account of the freshwater fisheries of Ceylon is given. The material for the present paper comes from data gathered by the authors over a period of fifteen years on the general setup of the fisheries and specific research carried out on a few major aspects of the fisheries. All the previous published work is gathered together. Most of the data available to the authors has been from the Polonnaruwa area, namely Parakrama Samudra and Minneriya tanks and Senanayake Samudra in the Gal-Oya Valley. Studies have also been made on Tilapia mossambica because of its great importance to the fisheries in general.

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In the present paper some preliminary remarks are made on the colour patterns of all the Potamonidae of Sri Lanka. In the opinion of the author more detailed studies will show that the colour pattern of each species is a useful diagnostic aid even with difficult species like those belonging to the "Ceylonensis" complex (Fernando, 1960). Fernando (1960, 1961) has described the species of Potamonidae. Eight species are known all belonging to the genus Paratelphusa. Only one species has been illustrated in colour so far (Fernando, 1960). Black and white pictures of all the other species except Paratelphusa soror (Zenthner) have been given in Fernando (1961). Paratelphusa soror is illustrated in the present paper.

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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 present study reports another seven species of flying fishes and brings the total for Ceylon to fifteen. Eleven of these fifteen species are represented in the author's collection. A key based on Breader (1938) and Parin (1960) and descriptive notes for these eleven species are given in this paper.

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Chemical analyses of fishes found in Sri Lanka were initiated by Lantz and Gunasekera (1957), who presented data from examination of 30 different species of fishes. Later Peiris and Grero (1972) published the analysed data of 5 more species. The present paper continues the analyses and the results obtained from 10 more varieties of marine fishes are given.

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The collection of Triclads from the Austrian-Ceylonese hydrobiological mission originates from 23 streams in the mountains of the south of Sri Lanka. All collected animals are of the Dugesia gonocephala (Dug.) type. Unfortunately the determinable mature animals were very rare in the samples but it seems certain that all the Triclads, found by the mission, belong to Dugesia nannophallus, described by Ball in 1970 after two individuals from Dunhinda, Badulla (Prov. Uva, Sri Lanka).

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The report deals with the material on freshwater crabs, collected by the Austrian-Ceylonese hydrobiological mission 1970 from the running waters of the mountains in south-west Ceylon. The locality records for Paratelphusa (Oziotelphusa) senex (Fabricius 1798) Paratelphusa (Ceylontelphusa) sorror (Zehntner 1894) and Paratelphusa (Ceylontelphusa) rugosa (Kingsley 1880), are described.

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A total of 378 specimens from 25 collecting localities belonging to 31 different species of fish collected mainly from the rivers of the hilly and mountain regions of the south-western and southern Ceylon have been identified and recorded. Ecological data and water analyses of these collecting localities are given.

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Data on age and growth of the following species were reviewed and von Bertalanffy's growth curves were fitted: Hilsa kelee, Decapterus russellii, D. macrosoma, Rastrelliger kanagurta, Pellona ditchela, Thryssa vitrirostris and Leiognathus equulus. For the five first species, microstructures in the otoliths were used for ageing. For most species growth curves based on size-frequency distributions are also presented. The reliability of the data presented is discussed.

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An analysis of growth of scad and mackerels on Sofala Bank, Mozambique, was performed using data collected from commercial vessels during the year 1986-87, using the "Compleat Elefan" software package. Updated estimates of growth parameters of Decapterus russelli, D. macrosoma (Carangidae), and Rastrelliger kanagurta (Scombridae) were obtained which take seasonal growth oscillations into account. Preliminary growth parameter estimates are also presented for Selar crumenophthalmus (Carangidae) and Saurida undosquamis (Synodontidae).

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The Annual report presents Scientific work carried out during the report year 1961 under the following: Scientific Work of the Organization Fisheries of Lake Victoria Commercial records Population analysis Rational exploitation Other species of Tilapia Small mesh gill net fisheries Bagrus docmac Investigation Lates Investigation Breeding studies on T. zillii & T. nigra The culture of Tilapia in ponds Migration of River Fish Hydrology and Algology Gear Research Buoy releases Vertical gill nets and lastly publications.

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In the present supplement, where records in the past have been few in a group, new records are given of localities both as regards species previously recorded from Sri Lanka and especially for new records. This gives the new records more standing and may enable others to collect these species. Over 50 species are recorded for the first time in Sri Lanka. A general survey of the freshwater fauna is attempted. This is intended to give an indication of the groups as regards their numerical status in species and the extent to which different groups have been investigated. Using this data on the invertebrate fauna, the prospects for introduction of invertebrates is discussed.

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In the present study the specimens collected by the Austrian-Ceylones hydrobiological mission 1970 are described. The freshwater gastropods in this study were collected from 100 different localities, mostly running waters, but some were also collected from stagnant waters like pools, irrigated paddy fields, swamps and water reservoirs (tanks). Listed from these localities are 31 species (and subspecies) 28 species are Streptoneura (=Prosobranchia), 3 species are Euthyneura-Pulmonata Basommatophora.