890 resultados para CORDERO, SEBASTIÁN, 1972-


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This is the River Dart Scale Reading Investigation Report on the 1972 season by the Devon River Board. The object of this investigation is to examine, by means of scale-reading, the general biology of the salmon population of the River Dart. In 1967 the final report on a five-year scale reading programme was summarised, at the time it was considered sufficient information to help with restocking programmes and the management of salmon population. But a further scale reading programme was started in an attempt to monitor changing patterns in salmon runs that may be caused by the new influences. It reviews the methods used for collection of the scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.

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This is the Second River Teign Fisheries Survey from July and August 1972 by the Devon River Authority. The aim of the survey was to assess the distribution and relative abundance of salmonid fish in the River Teign, describing the methods and results. The section on methods contains information of the selected transects and methodology for the survey. The results goes through totals of all salmonid fish caught, adults, parrs and estimations of parr population individually for salmo salar and salmo trutta. Maps with survey sections and fish indices along with tables with size distributions and totals of salmonids found are attached.

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This is the 7th Annual Report of the Rive Exe Scale Reading Investigation for the 1972 Season by the Devon River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon population of the River Exe. It reviews the methods used for the collection of scales and examination of the materials. It shows the results of the survey and the number of scales studied from each of the various sea-age classes, time of running with distribution of the sea-age groups throughout the season, fish sizes and smolt ages at migration. All is summarized in tables, and figures are included showing weight distributions for each age classes and frequency distributions.

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This is the Salmon Scale Reading Investigation from 1972 by Cornwall River Authority. The object of this investigation is to examine, by means of scale reading, the biology of age classes of the salmon populations of the River Tamar, River Tavy, River Lynher, River Fowey, River Camel and River Plym. It contains for each river the numbers of caught salmon, number of scales received and which were unreadable and percentages in each age group separately for net and rod caught. Length and weight frequency distribution histograms have been plotted to show the size distribution of the various sea age group.

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This is the Rivers Taw and Torridge scale reading investigation: the 8th annual report for the 1972 season produced by Devon River Authority in 1973. The object of the investigation is to examine by means of scale reading the biology of age classes of the salmon populations of the Rivers Taw and Torridge. The report is arranged in sections as previously and tables referred to in the report form an appendix. Scales were collected only from fish taken during the normal open season, which in 1972 was 1st April - 31st August. A weekly close time was in operation for the nets, a period of 60 hours from 6 p.m. on Friday evening to 6 a.m. on the following Monday. Thirty six licences for draft or seine nets were issued for the 1972 season and netsmen submitted samples of scales collected direct.

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A través de esta serie intentaremos conocer diferentes facetas personales de los integrantes de nuestra “comunidad”. El cuestionario, además de su principal objetivo, con sus respuestas quizás nos ayude a encontrar entre nosotros puntos en común que vayan más allá de nuestros temas de trabajo y sea un aporte a futuros estudios históricos. Esperamos que esta iniciativa pueda ser otro nexo entre los ictiólogos de la región, ya que consideramos que el resultado general trascendería nuestras fronteras.

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Mafia waters in the western Indian Ocean on the east coast of Africa is a natural attractive area for fishing. It has extensive coral beds which harbour good fish life and attracts sport fishery in the area. About 12 commercially important fishes listed are caught by sports fishermen. The data indicates that this area can become an attractive centre for sports fishery almost throughout the year with peak season from November to February. Long-term planning of the fishery is necessary. The conservation measures should be evolved and gan fishing, dynamiting or any other kind of distructive fishing should be prohibited. This area has natural potential to become a sports fishing centre in the future and a great attraction for tourists and anglers.

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I am particularly happy to write this short forward introducing the report of the Fisheries Department for the year 1972. The Fisheries Department of the Ministry of Animal Resources is responsible for directing the development, utilization and scientific management of the fisheries resources of Uganda. This ensures that our people continue to benefit from this resource not only as a revenue earner but also as a constant source of the much needed animal protein.

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Feeding habits of many animals have been used widely in animal classifications. This is so, because the type of diet an organism requires demands structural specialisation which will utilise the available resource. Many animals may however have many structural modifications to enable them to be described as omnivourous or generalised feeders such as H. empodisma and H. riponianus (GREENWOOD 1960) which may show varying degrees of structural and adaptational intermediacy between two trophic groups. Generally, however, the diet of many animals including fish changes as the animal grow larger. The change in structural modifications is usually correlated with changes in the diet. In fishes the change may involve change from tricuspid to biscuspid and finally to unicuspid type of teeth. The degree of modification in the structure depends on the diet, thus Haplochromis that feeds on soft tissues of snails only requires modifications in oral dentition while Haplochromis that feeds on both soft tissues and shells of snails require modification in the lower pharyngeal bone for grinding purposes. Other modifications connected with food utilisation may be located in the alimentary canal. (I) The fish species that are commercially exploited are Protopterus aethiopicus, Clarias mossambicus, Tilapia esculenta, Tilapia amphimelas and Tilapia hybrids. The other fish species present in the lake but not commercially exploited are: Gnathonemus sp. Alestes sp. Labeo sp., Barbus paludinoses, Barbus jacksoni, Barbus lineomaculatus, Barbus regersi, Leptogrlanis sp., Schilbe sp., Haplochromis spp. and Hemihaplochromis sp. (2) Protopterus sp. and Clarias sp. are mostly caught with hooks on long lines. There has been a steady increase in number of hooks on the lake. Since the stocks of Protopterus and C/arias in the lake have a limit, we should control the number of hooks used by each of the fishermen in order to avoid overharvesting. (3) All the previous studies on Lake Kitangiri fisheries suggested the use of gill nets with mesh size greater than 88.9 mm in order to avoid the capture of immature Ti/apia spp. But if the fishermen are to obtain economic gains from the fishery, the optimum mesh size for use is 88.9 -101.6 mm. (4) The gillnet is a passive gear with very beneficial selective characteristics. Unfortunately the drive-in fishery which exists on Lake Kitangiri more or less destroys the gillnet selectivity characteristics. It is therefore recommended that the beating of water with poles be discouraged and stopped. (5) There is need for provision of stable fishing canoes to replace the unstable bottle palm dug-out canoes which are currently being used and which are very risky to operate. (6) The fish processing facilities on Lake Kitangiri are still inadequate. Most of the fish is sun dried, Since sun drying is very difficult during the rainy season, most fishermen carry out intensive fishing during the dry season, Concentrating most of the fishing effort in anyone season instead of spreading evenly this effort over the whole year could damage the age structure of the exploitable stocks. (7) There are considerable fluctuations in the volume of water of the lake. The feasibility of regulating the water loss through the effluent Sibiti river should be investigated by the Water Development Department. (8) Damming the Sibiti river is an expensive undertaking and therefore, the Rural Development Bank of Tanzania should be asked to assess the economic feasibility of such a project.

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Wydział Historyczny: Instytut Historii

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De acuerdo a la normativa de TFEs el repositorio no puede dar acceso a este trabajo. Para consultarlo póngase en contacto con el tutor del trabajo. Puede acceder al resumen del mismo pinchando en el pdf adjunto.