39 resultados para Magdalen College (University of Oxford)

em Aquatic Commons


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Details are given of the Institute and its activities, in particular the research projects being undertaken. These include studies on the marine molluscs of Sierra Leone, the cockle fishery, a preliminary investigation on the fouling organisms affecting the raft-cultured oyster populations, larval oyster ecology in relation to oyster culture, preliminary studies on the reproductive cycle of the mangrove oyster (Crassostrea tulipa), and catch composition of fishes taken by beach-seines at Lumley (Freetown). Records of the west African manatee (Trichechus senegalensis) are noted.

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John Nathan Cobb (1868–1930) became the founding Director of the College of Fisheries, University of Washington, Seattle, in 1919 without the benefit of a college education. An inquisitive and ambitious man, he began his career in the newspaper business and was introduced to commercial fisheries when he joined the U.S. Fish Commission (USFC) in 1895 as a clerk, and he was soon promoted to a “Field Agent” in the Division of Statistics, Washington, D.C. During the next 17 years, Cobb surveyed commercial fisheries from Maine to Florida, Hawaii, the Pacific Northwest, and Alaska for the USFC and its successor, the U.S. Bureau of Fisheries. In 1913, he became editor of the prominent west coast trade magazine, Pacific Fisherman, of Seattle, Wash., where he became known as a leading expert on the fisheries of the Pacific Northwest. He soon joined the campaign, led by his employer, to establish the nation’s first fisheries school at the University of Washington. After a brief interlude (1917–1918) with the Alaska Packers Association in San Francisco, Calif., he was chosen as the School’s founding director in 1919. Reflecting his experience and mindset, as well as the University’s apparent initial desire, Cobb established the College of Fisheries primarily as a training ground for those interested in applied aspects of the commercial fishing industry. Cobb attracted sufficient students, was a vigorous spokesman for the College, and had ambitions plans for expansion of the school’s faculty and facilities. He became aware that the College was not held in high esteem by his faculty colleagues or by the University administration because of the school’s failure to emphasize scholastic achievement, and he attempted to correct this deficiency. Cobb became ill with heart problems in 1929 and died on 13 January 1930. The University soon thereafter dissolved the College and dismissed all but one of its faculty. A Department of Fisheries, in the College of Science, was then established in 1930 and was led by William Francis Thompson (1888–1965), who emphasized basic science and fishery biology. The latter format continues to the present in the Department’s successor, The School of Aquatic Fisheries and Science.

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In 2003, twelve marine protected areas were established in state waters (0-3 nmi) surrounding the Channel Islands. NOAA is considering extending this network (3-6 nmi) into deeper waters of the Channel Islands National Marine Sanctuary (CINMS). In order for effective long-term management of the deep water reserves to occur, a well-structured monitoring program is required to assess effectiveness. The CINMS and the National Marine Sanctuary Program (NMSP) hosted a 2-day workshop in April 2005 to develop a monitoring plan for the proposed federal marine reserves in that sanctuary. Conducted at the University of California at Santa Barbara, participants included scientists from academic, state, federal, and private research institutions. Workshop participants developed project ideas that could answer priority questions posed by the NMSP. This workshop report will be used to develop a monitoring plan for the reserves. (PDF contains 47 pages.)

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The growth of Sarotherodon (Tilapia) niloticus in Opa reservoir, University of Ife was determined from the fish scales. Compared with the growth in other similar water bodies the growth was comparatively faster in this newly-impounded reservoir

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Phosphorus removal by wetlands and basins in Lake Tahoe may be improved through designing these systems to filter storm water through media having higher phosphorus removal capabilities than local parent material. Substrates rich in iron, aluminum and calcium oftentimes have enhanced phosphorus removal. These substrates can be naturally occurring, byproducts of industrial or water treatment processes, or engineered. Phosphorus removal fundamentally occurs through chemical adsorption and/or precipitation and much of the phosphorus can be irreversibly bound. In addition to these standard media, other engineered substrates are available to enhance P removal. One such substrate is locally available in Reno and uses lanthanum coated diatomaceous earth for arsenate removal. This material, which has a high positive surface charge, can also irreversibly remove phosphorus. Physical factors also affect P removal. Specifically, specific surface area and particle shape affect filtration capacity, contact area between water and the surface area, and likelihood of clogging and blinding. A number of substrates have been shown to effectively remove P in case studies. Based upon these studies, promising substrates include WTRs, blast furnace slag, steel furnace slag, OPC, calcite, marble Utelite and other LWAs, zeolite and shale. However, other nonperformance factors such as environmental considerations, application logistics, costs, and potential for cementification narrow the list of possible media for application at Tahoe. Industrial byproducts such as slags risk possible leaching of heavy metals and this potential cannot be easily predicted. Fly ash and other fine particle substrates would be more difficult to apply because they would need to be blended, making them less desirable and more costly to apply than larger diameter media. High transportation costs rule out non-local products. Finally, amorphous calcium products will eventually cementify reducing their effectiveness in filtration systems. Based upon these considerations, bauxite, LWAs and expanded shales/clays, iron-rich sands, activated alumina, marble and dolomite, and natural and lanthanum activated diatomaceous earth are the products most likely to be tested for application at Tahoe. These materials are typically iron, calcium or aluminum based; many have a high specific surface area; and all have low transportation costs. (PDF contains 21 pages)

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The monthly and seasonal water requirements of a small fish pond (0.068ha; maximum capacity of 613.83m super(3)) at the University of Agriculture, Makurdi Fish Farm (Benue, Nigeria) were determined during the period of February to August 1996. The sources of water for the pond were rainfall, (103.4cm), run-off (6.3cm) and regulated inflow (95.0cm). The water loss for the period were Evapotranspiration, (106.74cm), Seepage (71.64cm) and regulated discharge (25.00cm). Evapotranspiration was identified as the main source of water loss while rainfall was the major source of water gain. The mean monthly water deficit was 24.56~c11.43cm while the mean monthly surplus was 9.84~c8.05cm. The quantity of water required to maintain the optimal water level in the pond was 474.00m super(3). Preliminary water budget of the study area showed that rainfed aquaculture can be effectively carried out at Makurdi during the months of June to October with supplementary inflows during the dry season months

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The studies reported were undertaken as part of a wide environmental feasibility study for the establishment of a modern sewage system in Freetown. The aim of this part of the study was to determine whether the hydrological regime of the Sierra Leone River Estuary would permit the large-scale introduction of sewage into the estuary without damaging the environment. The important factors were whether: 1) there would be sufficient dilution of the sewage; 2) fleatable particles or other substances would create significant adverse effects in the estuarine ecosystem. The outfall sites are described together with the sampling stations, methods and analyses. Results include: 1) T/S profiles; 2) chemical analysis of the water. A review of literature on the Sierra Leone River Estuary is included which provides information on the plankton, benthos and fisheries. Results suggest that at certain points where local circulations occur it would be inadvisable to locate untreated sewage outfalls. Such points are frequently observed in small embayments. These studies have been of short duration but the data can serve as baseline for more extended investigations which would give a more complete picture of the seasonal patterns in the estuary.

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This brief paper gives some notes on the geographical distribution and salinity tolerances of some Mugil species occurring in the Black-Johnson estuary, Sierra Leone

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This report gives the species and catch-rates per hour of some commercial shrimp species caught in the course of a short survey of inshore shelf fishing grounds. Species seen in significant quantities were: Parapenneopsis atlantica, Parapenaeus longirostris, Penaeus kerathurus and Penaeus duorarum notialis

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Pelagic fish (except for tuna) are landed in Sierra Leone mainly by the artisanal fishermen. The two most important species are Sardinella and Ethmalosa.Deep-sea species are normally exploited by purse seiners of foreign countries. The landings of artisanal fishermen largely comprise Sardinella eba.Landing data for Sardinella landed at Tombo and Goderich, and for Ethmalosa at Tombo, are presented in tabular form. Collection methods are described, with a definition of the unit of fishing effort, and a description of the gear used.The landing data are discussed with particular attention to fishing effort, catch per unit effort, and price per ton

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Sierra Leone is a tropical country where water temperatures are high throughout the year. Consequently the local oysters tend to spawn the year round, with one or two spawning peaks. The condition of such tropical oysters may not be as high as those oyesters in temperate countries since the stored glycogen is regularly utilized to form gonads. A high condition factor value indicates that the oysters have accumulated glycogen and or gonads, whereas a low condition factor value indicates that the oysters have spawned and are in the process of accumulating glycogen, which may later be utilized for gonad development. In oyster culture, condition factor studies may be supported by plankton and oyster spat settlement studies in the culture area. These studies give an indication of when oyster larvae and spat settlement are at their peak values. In Sierra Leone studies of the plankton and spat settlement are undertaken every week throughout the year. Conditions factor is obtained from the ratio weight of dry (oyster) meat x 1000/internal volume. Detailed condition factor values are shown in relation to salinity at two stations. Condition factor declines with reducing salinity, which principally occurs during the rainy season. The best times to collect spat are May to June and September to October