68 resultados para Fitting Trends


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EXTRACT (SEE PDF FOR FULL ABSTRACT): Observations show that global average tropospheric temperatures have been rising during the past century, with the most recent portion of record showing a sharp rise since the mid-1970s.

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EXTRACT (SEE PDF FOR FULL ABSTRACT): Observations of climate variables in the tropical Pacific region are examined for the period 1970-1994. We look at a variety of climate variables, including upper ocean temperatures, surface wind stress, precipitation, and the Southern Oscillation Index (SOI) and find evidence for two distinct decadal-scale warmings in the tropical Pacific ocean-atmosphere climate system during this period.

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The presence of even very minute quantities of pollutants may become harmful either due to their direct effect on zooplankton or indirectly due to the transfer of the pollutants to other trophic levels through zooplankton. The recent trend in marine pollution studies is therefore to find out the effects of very minute quantities of these pollutants on marine zooplankton and the methods of their accumulation and transfer to the organisms of higher trophic level including man. A review of laboratory and field studies concerning the effects of pollutants such as hydrocarbons, crude oil, heavy metals, pesticides and heated waste water on the survival, breeding, movement, faecal pellet production, growth and development on marine zooplankton is presented.

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The paper provides some background information about the developments in the prawn fishing technique. The important indigenous gear for prawns are the filtering type nets like the stake nets, boat seines and beach seines with bag. The only indigenous net, which can be compared in design with the modern bottom trawling gear, is the "Thuri Valai" of the Madras Coast. Prawns have also been reported from the catches of gill nets and cast nets. Dredges and beam trawls are simplest among the dragged gear. Even though several earlier attempts were made with the beam trawl, in 1959 season a detailed experiment was made to study the fishing features of this gear. The subsequent experiments conducted were for comparison with otter trawl, towing of 2 beam trawls one behind the other and the use of tickler chain. The initial experiments with otter trawls were mainly directed towards operational aspects. The experiments were to evaluate the effectiveness of fully mechanised and partially mechanised operation, the effect of extra buoyancy of floats and the use of tickler chain. Subsequent developments had been on the structure and design of prawn trawling gear. Effect of long wings and sweeps were tested. Catches of nylon and cotton nets were compared. The sizes of meshes of the cod-end have also been increased.

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Landing data of 21 fisheries from Karnataka (quarterly landings for the period 1956 to 1978 and annual landings for the period 1979 to 1981) were analysed to study the te111poral behaviour of the landings. The relative distribution and secular trends in each of the fisheries are reported. On an average, mackerel and oil sardine together account for about 70% of the annual landings. The fluctuation in the landings in all the fisheries was very high with the coefficient of variation attaining a minimum value of 61.53%. The inverse relationship between the landings of oil sardine and mackerel was found to be statistically significant. It is suggested that fishing effort be further increased in fisheries that have demonstrated a rising trend (about 73% of the total annual landings) as also in the case of the fisheries whose trends appear stagnant (about 21% of the annual landings). However, there seems to be some evidence of a need for regulating fishing in Hemirhamphus and Belone, Caranx and penaeid prawns. Regulations need to be made authentic with the help of sufficient information on not merely the fishery but on the whole population.

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There are concerns, at least among the proponents of development, on how to link policy development processes in Uganda and the associated transformation of the poor to high standards of living. In fact some questions have been posed as to whether it's the absence of poverty-targeted policies that a good proportion of individuals or communities are still poor. In the fisheries sector where most of the fish dependent communities live, poverty indications are still prevalent although arguments have been put that current reforms in the sector have transformed the lives of the fish dependent communities. The 1999/2000 household survey report indicates that the poverty levels reduced to 35% of Uganda's total population from 44% in 1997. The question that arose, which still arises anyway, was to define who is actually poor. When measuring poverty one is ultimately interested in the 'standards of living' of individuals especially those, whose standards of living are inadequate. The basic element of measuring this inadequacy/adequacy, at least in Uganda, is to use the household income or consumption per adult equivalent. Studies have demonstrated that household consumption expenditure is a good approximation of household income1. Therefore, for purpose of this report, we define poor households to mean based on that that one adopted by the Ministry of Finance to mean "households whose expenditure per adult equivalent falls below the poverty line 3 ". Many government documents report that the poverty line is one dollar a day. Therefore someone is below the poverty line if he or she lives on less than one dollar a day. In this paper, we analyse the evolution of poverty-driven policies that have been put in place by government and how these policies are shifting or are likely to shift the lives of fish dependent communities. We argue that combinations of poverty-policies are being translated into increased incomes and welfare of most individuals in the fisheries sector. The reasons for this shift, we argue, is as a result of a combination of factors all supported by non other that poverty-led government policies.

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The Tanzania part of Lake Victoria is the most important single fishery resource for the country. Past fishing practice caused disparity between the relative abundance in the catches and in the available stocks by overfishing some species while under-fishing others. Preliminary studies of distribution pattern, biomass estimates, etc, as derived from bollom trawl exploratory data, and the trend of the commercial catch statistics from 1958 to 1970, suggest that many of the commercially preferred species may not have the biotic potential 10 sustain higher yields under present ecological and fishing regimes. Haplochromis and a few other fish might be the only hope. Geographic extension of fishing to deeper waters may not be very promising as species diversificarion and fish density decline with depth. To develop and manage the fisheries, make full use of the resource and ensure economic and biological perpetuation of thc fishery, the appropriate fishing strategy cannot be properly developcd overnight.

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EAFFRO and UNPP/LVFRP bottom trawl exploratory data have been used to describe the depth distributional pattern. relative abundance and magnitude of the demersai fishes in Lake Victoria. The results have been compared with the commercial catch estimates, and various interpretations of the trends in the annual catches and experimental biomass estimates in relation to possible future developments of the fishery have been suggested. Though it is highly desirable to develop the fishery such as by supplementary trawling, certain social and biological consequences and considerations needs to proceed in graded steps guided by several research disciplines. The past trends of the fisheries of Lake Victoria are briefly considered. Recent exploratory bottom trawl data, by EAFFRO and UNDP/LVFRP, have been used to define demersal fish stocks of Lake Victoria in terms of their magnitude, relative abundance and distribution pattern by depth. Enstence of disparity between the relative abundance of the various species in their commercial catches and in their present biomass estimates is pointed out and the various aspects associated with the necessary modification of the fishing practices are discussed. Further and continuing research of the bio-socio-economic vectors of the fishery will be necessary in order to generate the rationale of an efficient fishing regime for a rational management strategy and realistic utilization of the fishery resource.