25 resultados para Ton
em Aquatic Commons
Resumo:
A half-ton capacity artificial dryer has been designed at the Central Institute of Fisheries Technology for drying fish like Mackerel, Sardine, White bait etc. The dryer is a hot air recirculation type. 80 KW thermostatically controlled heating coils are made use of for heating the air. The air is circulated by means of an axial flow pattern fan. Drying takes place at a temperature of 115 degrees F. The structure of the dryer comes to about Rs. 20,000.
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The sea bottom of the Wadge and Pedro Banks are covered with hard corals and rocks, which cause frequent damages to the net and sometimes total loss of the gear (Hamuro, 1966). This has been one of the main reasons why trawling had been restricted to a small area of the Wadge Bank until recent years.
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CONTENTS: Hon Mun MPA Pilot Project on community-based natural resources management, by Nguyen Thi Hai Yen and Bernard Adrien. An experience with participatory research in Tam Giang Lagoon, Thua Thien-Hue, by Ton That Chat. Experiences and benefits of livelihoods analysis, by Michael Reynaldo, Orlando Arciaga, Fernando Gervacio and Catherine Demesa. Lessons learnt in implementing PRA in livelihoods analysis, by Nguyen Thi Thuy. Lessons learnt from livelihoods analysis and PRA in the Trao Reef Marine Reserve, by Nguyen Viet Vinh. Using the findings from a participatory poverty assessment in Tra Vinh Province, by Le Quang Binh.
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Routine biostatistical port sampling data and landings records collected from the gulf menhaden purse seine fishery between 1974 and 1985 are updated. During most of the period, a total of 11 menhaden reduction plants operated in Mississippi and Louisiana, and the number of vessels in the purse seine fleet varied from 71 to 82. Total annual landings ranged from 447,100 metric tons in 1977 to the record landings for the fishery of 982,800 metric tons in 1984. Age-I and -2 gulf menhaden annually comprised almost 96% of the landings. Estimated total numbers of menhaden landed varied from 4,510.5 million in 1975 to 11,154.9 million in 1985. Annual mean lengths and weights of sampled fish-at-age showed lillie variation. Nominal or observed fishing effort gradually increased through Ihe 1970s and 1980s, reaching 655,800 vessel-ton-weeks in 1983. (PDF file contains 14 pages.)
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The Baltic Sea, the largest existing brackish water is a little smaller than the Baikal, which is a world heritage. The Baltic Sea is very young, less than 10 000 years, whereas the Baikal, which is of about the same volume, is the oldest lake with 25 million years. Not so long ago the Baltic was considered mainly as a recipient for effluents. Fisheries are administrated by the European Union in agreement with Russia. Fisheries in the Baltic could give, when optimally managed, some 900 000 ton fish a year, to less than 20 000 professional fisherfolk from nine nations. During the course of time they have developed different coastal cultures with different languages, not so well known outside their own countries. The proposal is made that the unique Baltic becomes a world heritage for food supply and for food production in a traditional way. This would lead towards a sustainable small scale fisheries and to maintaining food security. A cooperation between fisherfolk from different nations is essential. In order to raise the public interest in that important World heritage issue and additionally, how to better use fish resources from the Baltic sea, it is also suggested to arrange for a competition between coastal restaurants, offering food prepared from Baltic resources.
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ENGLISH: Isograms of sea surface temperature (OC) have been produced for 1949-1968 for the areas of the eastern Pacific Ocean in which the majority of the skipjack catch is taken. These are in the immediate coastal zone, California (35° N) to Chile (20 0 S), and the Revillagigedo and Galapagos Islands groups. Skipjack occurrence and apparent abundance (as CSDF, i.e., catch per standard days fishing, standardized in purse-seiner units) for 1951-1968 were then superimposed on the surface temperature isograms. Results show that skipjack occur at surface temperatures> 17° C but with the majority between 20°-30° C. Apparent abundance at CSDF > 1 ton/day is normally Iimited to 20°29° C water, except in two areas in certain years; from the Gulf of Tehuantepec to Cape Mala rates of 1-9 tons/day are relatively common at 29°-30° C, and off Chimbote (Peru) occasionally >9 tons/day are recorded down to 18° C. As expected there were no apparent relationships between annual thermal conditions in the coastal zone and skipjack abundance (total catch or indices of abundance) in the same or 2 subsequent years. An Appendix to the report determines the quantitative relationships between surface temperature and skipjack abundance in relatively small areal strata in Baja California waters in 1955 and 1958. Relationships generally appeared significant and opposite in these years when temperatures were respectively anomalously cold and warm. SPANISH: Se han producido isogramas de la temperatura de la superficie del mar (OC) para 1949-1968 correspondientes a las áreas del Océano Pacífico oriental en donde se obtiene la mayor parte de la captura de barrilete. Estas se encuentran ubicadas en la zona costanera inmediata, desde California (35°N) hasta Chile (200S) y en las Islas Revillagigedo y Galápagos. La ocurrencia de barrilete y su abundancia aparente (expresada como CDSP standardizada en unidades de cerqueros) para 1951-1968 fueron luego superpuestas en los isogramas de la temperatura superficial. Los resultados demuestran que el barrilete aparece en temperaturas superficiales de > 17°C pero la mayoría entre los 20°C-30°C. La abundancia aparente de la CDSP > 1 tonelada/día se limita normalmente a aguas de 20°-29°C, excepto en dos áreas en ciertos años; desde el Golfo de Tehuantepec a Cabo Mala las tasas de 1-9 toneladas/día son relativamente comunes en los 29°-30°C, y frente a Chimbote (Perú) se registran ocasionalmente> 9 toneladas/día a una temperatura tan fría como de 18°C. Como era de esperarse no existió una relación aparente entre las condiciones térmicas anuales de la zona costanera y la abundancia del barrilete (captura total o índices de abundancia) en el mismo año o en los 2 años siguientes. Un Apéndice del informe determina la relación cuantitativa entre la temperatura superficial y la abundancia del barrilete en un estrato de áreas relativamente pequeño en las aguas de Baja California en 1955 y 1968. Las relaciones generalmente aparecieron significativas y opuestas en esos años cuando las temperaturas fueron respectivamente anómalamente frías y calientes. (PDF contains 53 pages.)
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The definition of the newly introduced dimensionless parameter for tonnage measurement (German: Bruttoraumzahl (BRZ) (English: Gross tonnage (GT)) instead of Gross register ton (GRT) (German: Bruttoregistertonne (BRT) doesn’t seem to be so clear, neither for specialists. The present article gives some explanations about the history of measurement of ships and the relation between BRT and BRZ, especially for fishing vessels.
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The author endeavours to analyse the recent trend in the local production of fish by sector over a period of 5 years, 1980-1985 and the data available to the author on the Nigerian fish imports. The present and future deficit in fish production in Nigeria could only be met from the capture fishery and the fish farm industry but more likely from the latter. The production techniques involved in fish feed industry are illustrated in this paper with standard feed formulations to arrive at a suitable fish diet. Associated problems of fish feed industry and their possible solutions are highlighted. A case study of investment prospects in fish feed industry as well as the production of brine shrimps are suggested as possible areas of investments in the industry. The unit production cost of fish feed is about 700/ton, while in the case of artemia (brine shrimp), the estimated unit cost if about 400/ton
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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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We examined the diel ver-tical distribution, concentration, and community structure of ichthyoplank-ton from a single station 69 km off the central Oregon coast in the northeast Pacific Ocean. The 74 depth-stratified samples yielded 1571 fish larvae from 20 taxa, representing 11 families, and 128 fish eggs from 11 taxa within nine families. Dominant larval taxa were Sebastes spp. (rockfishes), Stenobra-chius leucopsarus (northern lampfish), Tarletonbeania crenularis (blue lan-ternfish), and Lyopsetta exilis (slender sole), and the dominant egg taxa were Sardinops sagax (Pacific sardine), Icichthys lockingtoni (medusafish), and Chauliodus macouni (Pacific viperfish). Larval concentrations generally increased from the surface to 50 m, then decreased with depth. Larval concentrations were higher at night than during the day, and there was evidence of larval diel vertical migration. Depth stratum was the most important factor explaining variability in larval and egg concentrations.
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William Francis Thompson (1888–1965) was a preeminent fishery scientist of the early to mid twentieth century. Educated at Stanford University in California (B.A. 1911, Ph.D. 1930), Thompson conducted pioneering research on the Pacific halibut, Hippoglossus stenolepis, from 1914 to 1917 for the British Columbia Provincial Fisheries Department. He then directed marine fisheries research for the State of California from 1917 to 1924, was Director of Investigations for the International Fisheries Commission from 1924 to 1939, and Director of the International Pacific Salmon Fisheries Commission from 1937 to 1942. He was also Director of the School of Fisheries, University of Washing-ton, Seattle, from 1930 to 1947. Thompson was the founding director in 1947 of the Fisheries Research Institute at the University of Washington and served in that capacity until his retirement in 1958. He was a dominant figure in fisheries research of the Pacific Northwest and influenced a succession of fishery scientists with his yield-based analysis of fishery stocks, as opposed to studying the fishes’environment. Will Thompson was also a major figure in education, and many of his former students attained leadership positions in fisheries research and administration.
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Commercial harvest of red sea urchins began in Washington state in 1971. Harvests peaked in the late 1980s and have since declined substantially in Washington and other areas of the U.S. west coast. We studied effects of experimental harvest on red sea urchins in San Juan Channel (SJC), a marine reserve in northern Washing-ton. We recorded changes in density and size distribution of sea urchin populations resulting from three levels of experimental harvest: 1) annual size-selective harvest (simulating cur-rent commercial urchin harvest regulations), 2) monthly complete (non–size selective) harvest, and 3) no harvest (control) sites. We also examined re-colonization rates of harvested sites. The red sea urchin population in SJC is composed of an accumulation of large, old individuals. Juvenile urchins represent less than 1% of the population. Lower and upper size limits for commercial harvest protect 5% and 45% of the population, respectively. Complete harvest reduced sea urchin densities by 95%. Annual size-selective harvest significantly decreased sea urchin densities by 67% in the first year and by 47% in the second year. Two years of size-selective harvest significantly altered the size distribution of urchins, decreasing the density of legal-size urchins. Recolonization of harvested sites varied seasonally and occurred primarily through immigration of adults. Selective harvest sites were recolonized to 51% and 38% of original densities, respectively, six months after the first and second annual harvests. Yields declined substantially in the second year of size-selective harvest because of the fishing down of the population and because of low recolonization rates of harvested sites. We recommend that managers consider the potential efficacy of marine harvest refuges and reevaluate the existing upper and lower size limits for commercial harvest to improve long-term management of the sea urchin fishery in Washington.
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A productive fishing ground for rock perch (Epinephelus fasciatus) was located off Ratnagiri between 17 degree 00' to 17 degree 10' N latitude and 72 degree 20' to 72 degree 30' E longitude, around a depth of 96m during November, 1983. An average catch of 2 ton/hr. was recorded. Length frequency studies of E. fasciatus indicate the probability of a nursery ground consisting of three brood stocks. Hydrographic studies of the ground revealed that the bottom water was oxygen deficient below a strong thermocline extending from 15-75 m depth with the recorded bottom temperature amounting to 20.5 degree C.
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Silver belly (Leiognathus Spp.) forms a major fishery in recent years in the Rameswaram island but fetches for the fishermen very low prices ranging from Rs. 0.03 to 0.12/Kg only, there being practically no demand for the fish. The possibilities of utilizing this cheap fish are discussed and the processing method described. During the glut season the cost of production of Silver belly fish meal works out to competitive prices of Rs. 500 to 700/ton. The silver belly fish meal is of high quality with good protein content averaging 57.71% in commercial samples and 61.90% in laboratory samples and with a high pepsin digestibility of 90.0% to 92.5%. The essential amino acid composition of the Silver belly fish meal compares very favorably with other round fish meals, with high contents of lysine, leucine, arginine, isoleucine, methionine, phenyl alanine, threonine and valine. Since there is good demand for fish meal as poultry and cattle food both in the internal and external markets, there is good scope for large scale production and sale of fish meal.
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A study on the effects of artificial feeds on the growth and production of fishes in polyculture in 6 ponds along with some limnological conditions was conducted. Species of Indian and Chinese major carps (Labeo rohita, Catla catla, Cirrhinus mrigala, Hypophthalmicthys molitrix) and catfishes (Clarias batrachus, Clarias gariepinus) were stocked in 6 ponds. Stocking rate in both cases were 32044 fingerlings per hectare. Ratio of species of Rui:Catla:Mrigal:Silver carp:African Magur:Local Magur=25%:25%:5%:25%:14%:6%. Fertilization and artificial feeds were given in 3 ponds (treatment I) and only fertilization was done in other 3 ponds (treatment II). Average yield/ha/yr was 7.903 m.ton in case of fertilization and artificial feeding application and 3.374 m.ton in case of only fertilization application. Urea, TSP and cow dung were applied fortnightly at the rates of 400 kg/ha/yr, 2000 kg/ha/yr and 4000 kg/ha/yr respectively. Wheat bran, rice bran and mustard oil cake were given daily as an artificial feed in treatment I. Whereas treatment II was conducted without any artificial feed. Ratio of artificial feed was wheat bran:rice bran:oil cake=2:2:1 (by wt). Absence of artificial feed in 3 ponds under treatment II seriously affected the growth and production of fish.