906 resultados para Food Habits
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The paper viewed the decline in information provision in Nigeria to poor library development, which could be attributed to poor funding. The consequence is that current journal and books are not available in nigerian fisheries libraries. Information which can be regarded as the first factor of production on which other factors like land, labour and capital depend, can only be provided at the right time when libraries are better founded. For now if there must be increase in fish production, poverty alleviation and food security in Nigeria, our fisheries scientists and policy makers will have to rely on international sources of information using the advantage of internet connectivity. Some of such sources discussed in this paper are ASFA, AGORA, FAO DOAJ, FISHBASE, IAMSLIC, INASP, INASP-PERI, INASP-AJOL, ODINAFRICA, SIFAR, WAS, and ABASFR. However, reliance on international sources must not be at the total neglect of harnessing nigerian fisheries information. For the Nigerian Fisheries and Aquatic Sciences Database being developed by NIFFR to attain an international status like those enumerated above, scientists and publishers are requested to take the pain of depositing copies of their publications with NIFFR for inclusion in the Database
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Man-made lakes inhabit diverse species of which the fish fauna constitutes the most targeted species of exploitation. For man-made lakes to serve as means of alleviating poverty an enhancing food security through increased fish production in Nigeria, sound management of the lake is strongly recommended. It will include the maintenance of good water quality, stocking with good species, control of over fishing, conservation of extinction and declining species as well as adequate legislation to regulate fishing activities. Recreational and tourism facilities can also be incorporated along with fish production in these man-made lakes to provide additional income and revenue for individual and Government. Some other practical ways by which these water bodies can be improved for effective and sustainable fish production as well as alleviating poverty was discussed
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The effects of substituting fish meal with grasshopper meal in fish diets on the growth, food utilization and survival of the Nile tilapia, Oreochromis niloticus (mean weight = 40.1g) were investigated. The results show that the best growth and food utilization were recorded in the fingerlings fed in the 10% grasshopper meal and 30% fish meal while the poorest growth and food utilization indexes were recorded with the 25% grasshopper meal and 15% fish meal. In general, at 10% inclusion, the fingerlings performed even better than the control (40% fishmeal and no grasshopper meal)
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This is the report on the workshop on “Small Indigenous Freshwater Fish Species: Their Role in Poverty Alleviation, Food Security and Conservation of Biodiversity”, organized by the International Collective in Support of Fishworkers(ICSF) in collaboration with the Inland Fisheries Society of India (IFSI). The workshop was a forum for exchange of views on the role of small indigenous freshwater fish species (SIFFS) in enhancing rural food supply and livelihood security, and in conserving biodiversity. The workshop also discussed the socioeconomic and cultural contexts for the culture and capture of SIFFS, and how to enhance access—especially for women—to better incomes, livelihoods and nutritional security, through appropriate policy spaces. This report provides a fresh focus on SIFFS, usually regarded as ‘trash’ fish. It urges scientists, researchers and decisionmakers to develop policy and legislative measures to ensure the conservation and promotion of SIFFS, both in capture- and culture-fisheries systems. This report will be useful for fishworker organizations, researchers, policymakers, fish farmers, members of civil society and anyone interested in fisheries and livelihoods. (PDF contains 86 pages)
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O presente estudo avaliou os padrões de consumo alimentar entre adultos brasileiros e a sua associação com o Índice de Massa Corporal (IMC). Em 1996/1997, o Instituto Brasileiro de Geografia e Estatística (IBGE), coletou dados antropométricos, de consumo alimentar e socioeconômicos de 9351 indivíduos entre 20 e 60 anos, moradores das áreas urbanas e rurais das regiões Nordeste e Sudeste do Brasil. Através da análise de componentes principais foram identificados os padrões de consumo alimentar. A associação entre os padrões de consumo alimentar e o IMC foi avaliado através de regressão linear. A prevalência de obesidade (IMC >= 30 kg/rn2) foi de 2,7% entre homens moradores das áreas rurais e em torno de 8,0% para os moradores da área urbana, em ambas as regiões. Entre as mulheres, esta prevalência na área rural foi de 6,5% no Nordeste, 14,3% no Sudeste e em torno de 12% nas áreas urbanas. A prevalência de sobrepeso (IMC>= 25 kg/m2) na área rural foi, aproximadamente, 20,0%para o sexo masculino e 24,0% para o sexo feminino, ficando ao redor de 30% nas áreas urbanas. Identificou-se três padrões de consumo: o padrão 1 (misto), com o consumo de quase todos os alimentos, o padrão 2, um padrão a base de arroz, farinha e feijão, composição característica da dieta tradicional do brasileiro, e o padrão 3, onde poucos alimentos explicaram a variação de consumo, contudo, estes alimentos variaram nas quatro áreas. Ajustando-se para idade, renda, escolaridade e atividade física, o padrão misto associou-se positivamente com o IMC (p<0,003), exceto no Sudeste rural (p=016). A dieta tradicional no Sudeste rural (p=0,007) e o padrão 3, composto por tubérculos, farinha e carne, no Nordeste urbano (p=O,0004), associaram-se negativamente com o IMC. Concluiu-se que o padrão misto se associou positivamente ao IMC, sugerindo que o consumo calórico total, mais do que o padrão da dieta, explicaria o aumento da obesidade observado no Brasil.
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The authors have been studying the control of phytoplankton biomass in several Australian reservoirs. To manipulate fish communities in order to reduce phytoplankton biomass, one needs a thorough understanding of processes in the plankton-associated food webs. In contrast to the situation found in lakes of the northern hemisphere, the planktivorous fish of Australian reservoirs are relatively small and they may deplete small rather than large zooplankters, so that animals as large as the adults of Daphnia carinata may avoid predation. This would result in promotion of Daphnia, particularly if fish eliminate its smaller competitors. The aim of biomanipulation should be the establishment and maintenance of a proper ratio of planktivores/piscivores, adequate for water quality requirements. Successful selection of the appropriate ratio for a given reservoir will depend on the extent of our understanding of its food web interactions. For practical application of biomanipulation in management, further development of the food web theory under Australian conditions is needed.
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Abstract Growth and condition of fish are functions of available food and environmental conditions. This led to the idea of using fish as a “consumption sensor” for the measurement of food intake over a defined period of time. A bio-physical model for the estimation of food consumption was developed based on the von Bertalanffy model. Whereas some of the input variables of the model, the initial and final lengths and masses of a fish and the temperature within the time period considered can easily be measured, internal characteristics of the species have to be determined indirectly. Three internal parameters are used in the model: the maintenance consumption at 0°C, the temperature dependence of this consumption and the food efficiency, the percentage of the ingested food utilized. Estimates of the parameters for a given species can be determined by feeding experiments. Here, data from published feeding experiments on juvenile cod, Gadus morhua L., were used to validate the model. The average of the relative error for the food intake predicted by the model for individual fish was about 24 %, indicating that fish used the food with different efficiencies. However, grouping the fish according to size classes and temperature lowered the relative error of the predicted food intake for the group to typically 5 %. For a group containing all fish of the feeding experiment the relative prediction error was about 2 %. Zusammenfassung Wachstum und Kondition der Fische sind von der verfügbaren Nahrung und von Umweltbedingungen abhängig. Dies führte zur Idee, Fisch als „Konsum-Sensor“ für die Messung der Nahrungsaufnahme über einen definierten Zeitraum zu verwenden. Auf Grundlage des von Bertalanffy-Modells wurde ein bio-physikalisches Modell zur Schätzung der Futteraufnahme entwickelt. Während einige der Eingangsgrößen des Modells leicht gemessen werden können (Anfangs- und Endlänge und -körpermasse der Fische und die Temperatur innerhalb des betrachteten Zeitraum), können interne Parameter der betrachteten Art nur indirekt bestimmt werden. Drei interne Parameter werden in dem Modell verwendet: Die Erhaltungskonsumtion bei 0° C, die Temperaturabhängigkeit dieser Rate und der Wirkungsgrad der Nahrung (der Anteil der Nahrung ,der aufgenommen und verwendet und nicht ungenutzt wieder ausgeschieden wird). Die Modellparameter für eine bestimmte Art können durch Fütterungsversuche bestimmt werden. Um das Modell zu validieren wurden Daten aus veröffentlichten Fütterungsversuchen mit juvenilen Kabeljau (Gadus morhua L.) verwendet. Modell und Wirklichkeit weichen in der Regel voneinander ab. Der durchschnittliche relative Fehler der durch das Modell vorhergesagten Nahrungsaufnahme betrug für Einzelfische etwa 24%, was darauf hinweist, dass einzelne Fisch die Nahrung mit unterschiedlichen Wirkungsgraden verwerten. Allerdings senkte die Gruppierung der Fische nach Größenklassen und Temperatur den relativen Vorhersagefehler für die Nahrungsaufnahme der Gruppe auf etwa 5%. Für alle Fische im Fütterungsversuch ist der relative Vorhersagefehler etwa 2%.
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The economic, environmental and social benefits of more sensitive land use practices that protect or restore the natural functions of river catchments have been widely discussed. Changing land use has implications for a wide range of other biological communities. Some studies have already been undertaken on the benefits of sensitive farming at the catchment scale in England and Wales. However, there is a gap in these studies at the local scale, and particularly for upland farms from which headwaters arise. This article documents a case study relating to a successful partnership in Cumbria, UK, set within the wider context of catchment management. Whilst the case study is not highly detailed, and some costs have been described in outline only to protect confidentiality and commercial sensitivity, it provides some generic lessons and may therefore be useful in informing more sustainable policy-making. High Hullockhowe Farm near Haweswater, which was used a the case study highlighting changes in farm practise, costs and benefits, water resources and biodiversity. The authors relate the case study to wider policy implications.
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As is known, copepods play an important role in the nutrition of fish. Therefore with a view to facilitating research on the study of the quantitative side of feeding, there have recently appeared a considerable number of papers devoted to the development of methods for determining the wet. weight of these crustaceans. For the further facilitating of research in the nutrition of fish it would be of great interest to clarify the problem, is there not some kind of rule in the growth of the crustaceans during metamorphosis, and if there is such a rule is it not possible, to determine the length of the larvae at each stage, not by measuring them, but by using the formulae derived on the basis of these rules. This article examines the growth curves of different species of freshwater Copepoda, obtained on the basis of experimental observations in cultures or by way of measurement of mass material at all stages of development in samples from water-bodies. The authors study in particular the ratio of the mean diameter of the eggs to the mean length of the egg-bearing females.
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When dissolved in water, compounds of nitrogen and phosphorus ought to contain the basic assimilated food requirements for autotrophic plants and therefore autotrophic algae. This article summarises the occurrence of nitrogen in water, how species of algae utilize nitrogen and phosphorus forms for growth and the capacities of algae to adapt to environments of different nutrient wealth. This topic has unquestionable importance not only for the purpose of survival of a species but also in deciding indirectly about the stability of ecosystems.
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The Goggausee, in spite of its modest depth (Zmax = 12 metres), shows meromictic properties: autumn and spring circulation extend only to a depth of 8 metres. The water layers below about 10 metres are constantly oxygen-free, the critical zone with at least intermittent oxygen loss lies at a depth of between 6 and 10 metres. A limnological excursion in May 1974 offered an opportunity to investigate the daily vertical migration of the species Chaoborus flavicans with reference to its food supply of zooplankton as well as the chance to carry out some preliminary experiments on its rate of food intake. Among the studied features were the planktonic depth distribution of Chaoborus flavicans and the food intake of Chaoborus larvae under experimental conditions.
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Despite the fact that it is a long time sinc e the methods of collection and quantitative estimatio n of protozoa were worked out data on the abundance of these animals in freshwaters are not very numerous. Nevertheless, Infusoria and Rhizopoda at high densities are widespread in the water and sediments of lakes and reservoirs. In order to find ou t the importance of infusoria as a food source for cyclopoids we carried out experimental investigations using C14. For this three species of cyclopoids, widely distributed in open regions of Rybinsk reservoir were selected: Cyclops vicinus, Mesocyclops oithonoides and Kesocyclops leuckarti. The data presented give evidence that the species investigated are able as predators to consume infusorian plankton arid bacteria in the form of flocs or small clumps of detritus.
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This review deals with the variation in populations of invertebrates and the relationships between invertebrate production and detrital food material in chalk streams. The total quantity of detrital material processed by invertebrate consumers is many times greater than the production of these consumers. The amount of detritus ingested each year by chalk stream invertebrates may well be similar to the annual input of autochthonous primary production plus that from allochthonous tree cover.
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In most lakes, zooplankton production is constrained by food quantity, but frequently high C:P poses an additional constraint on zooplankton production by reducing the carbon transfer efficiency from phytoplankton to zooplankton. This review addresses how the flux of matter and energy in pelagic food webs is regulated by food quantity in terms of C and its stoichiometric quality in terms of C:P. Increased levels of light, CO2 and phosphorus could each increase seston mass and, hence, food quantity for zooplankton, but while light and CO2 each cause increased C:P (i.e. reduced food quality for herbivores), increased P may increase seston mass and its stoichiometric quality by reducing C:P. Development of food quality and food quantity in response to C- or P-enrichments will differ between 'batch-type' lakes (dominated by one major, seasonal input of water and nutrients) and 'continuous-culture' types of lakes with a more steady flow-rate of water and nutrients. The reciprocal role of food quantity and stoichiometric quality will depend strongly on facilitation via grazing and recycling by the grazers, and this effect will be most important in systems with low renewal rates. At high food abundance but low quality, there will be a 'quality starvation' in zooplankton. From a management point of view, stoichiometric theory offers a general tool-kit for understanding the integrated role of C and P in food webs and how food quantity and stoichiometric quality (i.e. C:P) regulate energy flow and trophic efficiency from base to top in food webs.From a management point of view, stoichiometric theory offers a general tool-kit for understanding the integrated role of C and P in food webs and how food quantity and stoichiometric quality (i.e. C:P) regulate energy flow and trophic efficiency from base to top in food webs.