28 resultados para Middle English romances

em Aquatic Commons


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Espanol: En la presente lista bibliográfica fueron recopiladas las referencias sobre los peces continentales de la Argentina, del período comprendido entre mediados del siglo XVIII y fines del año 2005. Incluye las listas bibliográficas publicadas durante los años 1981 a 2004, y las citas no mencionadas en ellas. Se incluyeron el ISSN o ISBN según correspondiera, la abreviatura oficial y el lugar de origen de las publicaciones. En algunos casos, los ISSN, las abreviaturas de los nombres de las publicaciones o su procedencia, mencionados en los catálogos, no coinciden con los de la home page de la publicación. Una bibliografía puede ser muy rica y aún estar incompleta. Requiere de sus lectores algún interés histórico, y aún un interés profundo por su tema. Ante una bibliografía, muchos investigadores preferirían no encontrar algunas referencias, y de hecho, muchas son oportunamente olvidadas. Por no saber como hacerlo, o por menosprecio, estas listas raramente son citadas en los trabajos, aunque sobre algunos temas en particular, sería realmente difícil formarse una idea si las bibliografías no existieran. Aún desde el comienzo es complicado precisar un criterio de inclusiones. Por ejemplo, gran parte de la ictiofauna Argentina se encuentra también en Brasil. ¿Justifica esto incluir informes perdidos sobre artes de pesca en una cuenca distante? ¿Deben los clásicos, que todo el mundo conoce y el que se inicia encontrará sin dificultad, ser incluidos? Aún a un grupo que se dedicara full time a este trabajo, le sería difícil verificar la precisión de las citas antiguas, en las que fechas y autoría cambian según la investigación histórica. En una bibliografía más o menos general, la perfección atenta contra la publicación. Sin embargo, pensamos que es conveniente hacerlas. Una mirada a este volumen, muestra la enorme cantidad de desarrollos en muchos temas, y la regla que uno de nosotros ha mencionado desde hace tiempo: siempre hay más publicado sobre un tema de lo que uno cree. La sospecha de que con sólo mirar lo que está hecho, muchos subsidios podrían utilizarse para algo más útil que algunas evaluaciones repetidas de recursos o biodiversidad, es un poco pesimista y no haremos perder trabajos insistiendo en eso. Cada generación elige sus metas, su propia base epistemológica, sus trabajos preferidos y los que desecha. Aún en trabajos perdidos o de mala calidad, es posible encontrar datos valiosos. Ningún proyecto, por mejor diseñado que esté, podrá mostrar en el presente los organismos que vivían en el pasado en un lugar en el que las condiciones han cambiado, o lo hará en términos de otra disciplina. En los temas aplicados la información del pasado puede ser importantísima. Aún en una disciplina tan conservadora como la nomenclatura, los cambios pueden ser exasperantes; no pueden serlo menos en las que intrínsecamente, como la ecología, es lo que estudian. Para dar una idea más precisa del desarrollo de la ictiología en la Argentina, esta lista podría ir acompañada de una apreciación crítica. Entendemos que una tarea así exige un trabajo diferente, de cierta magnitud y con no pocos elementos históricos. Aunque tiene deficiencias, la ictiología argentina constituye una acumulación de conocimientos de considerable calidad y pertinencia para la historia natural de América del Sur. Dejamos a los lectores que cada uno haga la suya. English: For the present list, references on freshwater fishes of Argentina were compiled from the period between middle XVIII Century and the end of the year 2005. It includes previous lists published during 1981 to 2004, and references not mentioned therein. The ISSN o ISBN numbers were included, as well as the official abbreviations and the place of origin of the periodicals. In some cases, these data as quoted in catalogs, do not agree with those in the home page of the publication. A bibliography may be very rich and anyway never complete. It requires from its readers some historic interest and indeed a deep interest on his (her) subject. Browsing a bibliography, many researchers would prefer not to find some references, and in fact, sometimes they forget some of them. Not imagining how to do it, or because people do not concede importance to them, bibliographic lists are rarely quoted in papers, though some subjects would be rather difficult to understand if list of publications would not exist. Even from the beginning, it is difficult to precise a criterion of inclusions. For example, many Argentine fishes occur also in Brazil. Does this justify the inclusion of grey reports on a distant basin? Should classic works, that everybody knows and are easily found, be included? Is near impossible, even for a group dedicated full time to this work, to verify the precision of old citations, whose dates and authorship change according to authorities and historical research. In a more or less general bibliography, completeness is against publication. Nevertheless, we think that is convenient to prepare these lists. A look at this volume shows the enormous developments in many subjects, and the rule that one of us mentioned long ago: there are always more papers on any subject than one suspects. Looking at what has already been done raises the suspicion that many grants could be used for something more useful than repeated evaluations of biodiversity or resources. This is a bit pessimistic, and we do not want to erase working opportunities. Each generation chooses its targets, its own epistemological base, its preferred papers and those that rejects. Even in lost or bad quality papers, the possibility of finding valuable information exists. No project, whatever the appropriateness of its design, could show at present which organisms lived in the past in a place where environmental conditions have changed, or it will do it in terms of another discipline. In applied subjects, information from the past can be very important. Even in a conservative discipline as nomenclature, changes can be exasperating. They are not lesser in those like ecology, where change itself is studied. To provide a more precise idea of the development of ichthyology in Argentina, this list could be accompanied by a critical appreciation. We understood that such an aim requires a different work, with no few historical elements and of certain magnitude. In spite of some deficiencies, Argentine ichthyology, resulting from collaboration of both local and foreign people, constitutes a bulk of knowledge of considerable quality and pertinence for the natural history of South America. We leave each reader to make his (or her) own evaluation. (Texto en Espanol. PDF tiene cien setenta paginas.)

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This cruise report is a summary of a field survey conducted in coastal-ocean waters of the Mid-Atlantic Bight from Nags Head, North Carolina to Cape Cod, Massachusetts and from approximately 1 nautical mile (nm) of shore seaward to the shelf break (100 m). The survey was conducted May 12 - May 21, 2006 on NOAA Ship NANCY FOSTER Cruise NF-06-06-NCCOS. Multiple indicators of ecological condition were sampled synoptically at each of 49 stations throughout the region using a random probabilistic sampling design. Samples were collected for the analysis of benthic community structure and composition; concentrations of chemical contaminants (metals, pesticides, PAHs, PCBs, PBDEs) in sediments and target demersal biota; nutrient and chlorophyll levels in the water column; and other basic habitat characteristics such as depth, salinity, temperature, dissolved oxygen, pH, sediment grain size, and organic carbon content. The overall purpose of the survey was to collect data to assess the status of ecological condition in coastal-ocean waters of the region, based on these various indicators, and to provide this information as a baseline for determining how environmental conditions may be changing with time. The results will be of value in helping to broaden our understanding of the status of ecological resources and their controlling factors, including impacts of potential ecosystem stressors, in such strategic coastal areas. (18pp.) (PDF contains 24 pages)

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Summer flounder, Paralichthys dentatus, scup, Stenotomus chrysops, and black sea bass, Centropristis striata, cooccur within the Middle Atlantic Bight and off southern New England and are important components of commercial and recreational fisheries. The commercial otter trawl fishery for these species is primarily a winter fishery, whereas the recreational fishery takes place between late spring and autumn. The otter trawl fishery generally targets summer flounder, and less frequently scup, while black sea bass occurs as bycatch. Trips in which all three species were present yielded highest aggregate landings per unit of effort (LPUE) levels and occurred more often than trips landing only one or two species. More than 50% of the trips in the trawl fishery landed at least two of the three species. In contrast, greater than 75% of the recreational landings of each species occurred as a result of trips landing only one species. Differences in the fisheries resulted from the interactions of seasonal changes in species distributions and gear selectivity. (PDF file contains 18 pages.)

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Monitoring of the waters of the Middle Atlantic Bight and Gulf of Maine has been conducted by the MARMAP Ships of Opportunity Program since the early 1970's. Presented in this atlas are portrayals of the temporal and spatial patterns of surface and bottom temperature and surface salinity for these areas during the period 1978-1990. These patterns are shown in the form of time-space diagrams for single-year and multiyear (base period) time frames. Each base period figure shows thirteen-year (1978-1990) mean conditions, sample variance in the form of standard deviations of the measured values, and data locations. Each single-year figure displays annual conditions, sampling locations, and departures of annual conditions from the thirteen-year means, expressed as algebraic anomalies and standardized anomalies. (PDF file contains 112 pages.)

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Biological studies of Heterotis niloticus were conducted for three years in the middle River Niger. Scales were found to be the most suitable structure in ageing Heterotis which was validated by length/histogram curve. Annual rings were found to be formed between March to June. Growth was rapid in the first two years and they reached sexual maturity at 2 years. The male grow longer while the female are bulkier. The length-weight relationship of male and female Heterotis did not differ significantly and the resulting equation for male was W = 1.25L super(2.5) and W = 1.6L super(2.7) for females respectively where W = weight (g) and L = total length. The total length to body scale relationship was found to be L = 14.3R super(2.6) where (R = oral radius of scale Heterotis growth was found to be allometric

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Samples of planktonic algae from major lakes in the English Lake District have been investigated over many years as part of a long-term monitoring programme set up by the Freshwater Biological Association and continued by the Institute For Ecology. Some lakes have been sampled regularly for long periods, others less frequently or only occasionally. Windermere north and south basins, and the neighbouring lakes Blelham Tarn and Esthwaite Water, have been under observation, mostly on a weekly basis, since the programme began in 1945. During this time diatoms have played a significant role in the population dynamics of these lakes.

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This article is based on a survey of tarns conducted mainly in the summers of 1983 to 1985, plus a survey made in the winter of 1985, in which streams were sampled on the wide variety of rock-types occurring on the fringes of the Lake District. Differences in composition of major ions and their concentrations in the surface waters of Cumbria reflect the complex geological structure of the region. At altitudes above 300 m, on Borrowdale Volcanics and Skiddaw Slates, surface waters are derived from atmospheric precipitation, with additional inputs of some ions - especially calcium and bicarbonate - from catchment rocks and soils. In some of the low-lying large lakes on the fringes of the central fells, water composition is also dominated by inputs from upper catchments; examples are Wastwater, Ullswater and Haweswater. However in other lakes there is evidence (Derwentwater and Bassenthwaite Lake) of inputs from saline groundwater.

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For more than 55 years, data have been collected on the population of pike Esox lucius in Windermere, first by the Freshwater Biological Association (FBA) and, since 1989, by the Institute of Freshwater Ecology (IFE) of the NERC Centre for Ecology and Hydrology. The aim of this article is to explore some methodological and statistical issues associated with the precision of pike gill net catches and catch-per-unit-effort (CPUE) data, further to those examined by Bagenal (1972) and especially in the light of the current deployment within the Windermere long-term sampling programme. Specifically, consideration is given to the precision of catch estimates from gill netting, including the effects of sampling different locations, the effectiveness of sampling for distinguishing between years, and the effects of changing fishing effort.

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Bassenthwaite Lake is, in many ways, different from the other major lakes in the English Lake District: it is the most northerly, the shallowest, has the largest catchment and the shortest mean retention time. There is also considerable temporal variation in lake level. This article summarises the limnological features of Bassenthwaite Lake, the catchment and physical characteristics before describing the water chemistry, phytoplankton, macrophytes, zooplankton, invertebrates, fish, mammal and invertebrate population. The authors then describe the ecological pressures faced by Bassenthwaite Lake such as nutrients, sediments and introduced species.

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The Siberian Dace (Leuciscus leuciscus baicalensis (Dyb)is an important trade fish in Siberian waters. In the Ob basin more than 30,000 centners are produced annually. Catches of dace fluctuate significantly both between different rivers and between years in the Tomsk region. Defining the stocks of dace in the waters of the Tomsk region and explaining the fluctuations over time seems to be a very important and relevant question for the workers of the fishing industry. An answer, however, requires an accurate knowledge of the biology of dace; its reproductive, feeding and migration habits and the conditions of wintering etc. In the following we examine one of the above questions i.e. the biology of the reproduction of dace. The study was carried out in the Middle Ob in May 1951. This tranlations provides the introduction, summary and table captions only of the original article.

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This paper describes some characteristic features of the phytoplankton of Grasmere, one of the smaller of the principal lakes of the English Lake District, and attempts to relate these to distinctive physical and chemical properties of the lake. Quantitative data presented herein are derived from 5-m vertical column samples, collected with a flexible polyethylene hose close to the deepest point of Grasmere, generally at intervals of 14 days ( 7 days from 1972 to 1978, inclusive). The study concludes that although Grasmere has been subject to increased phosphorus-loading and has quickly developed many features associated with eutrophication, the composition of its plankton has retained the characteristics of a mesotrophic, soft-water lake: a vernal diatom maximum, generally dominated by Asterionella, is followed by summer growths of nanoplanktonic species, of various colonial Chlorophyceae, before a substantial return to Asterionella-dominance in the autumn.

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There is no evidence of an increase in the acidity (lower pH or alkalinity) of water-bodies in the Lake District over the last 50 years. Brown trout occur in acid streams and upland tarns where pH is 4.5-5.2 throughout the year. Their occurrence in such waters in Britain and Ireland has been known for most of this century and there is no previous evidence of harmful effects on salmonid fisheries, though numbers of fish are naturally low. However, many benthic invertebrates that are common in hill-streams where pH is above 5.7 do not occur in more acid streams. This phenomenon occurs in the headwaters of several western rivers in Cumbria. It is not a recent response to "acid rain". Harmful effects of pH are undoubtedly more pronounced in waters that are poor in other dissolved ions. Low concentrations of sodium, potassium, calcium and chloride are especially important and may limit the distributions of some aquatic animals even where pH is above 5.7. The concentration of sulphate ions is usually relatively high but this is not important to the fauna; concentrations are at least two times higher in productive alkaline water-bodies than they are in unproductive acid waters.

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The author reviews the stratigraphic diatom profile of Cumbrian lakes since the last glaciation. Knowledge of both present and previous interglacials suggests that a natural cycle of change is imposed on all lakes. The nature of inwashed material is dependant on climatic and natural soilcycles and this affects the water quality and sensitive aquatic biota. Anthropogenic effects are superimposed upon this with forest clearance and pollution. Whilst some Cumbrian diatom profiles extend over the entire post glacial, others cover only detailed sections relating to particular problems. Causes and effect of recent changes in lakes can be studied using indicator species but palaeocology contributes greatly to understanding of long term changes.

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The value of specially designated sites in conserving biodiversity has been a hotly debated issue for many years. The debate has recently been given fresh impetus by the creation of Natural England, the new Government Agency responsible for the protection and enhancement of the natural environment in England, and the challenges facing the management of designated sites resulting from the increasingly tangible effects of climate change. In the freshwater environment, the role of designated sites is very much under the spotlight because of the implementation of the European 'Water Framework' Directive, which aspires to holistic, ecologically-based management of aquatic habitats.This paper explores the underlying premises of, and rationale for, special site designations for wildlife, and provides a frank account of the inevitable clash of management philosophies that designated sites create in the freshwater environment, drawing on experiences of managing designated freshwater sites in England over the past decade. A positive role is outlined for designated sites in freshwater conservation, which addresses these management conflicts in a way that not only meets Government obligations towards these sites but also paves the way for enlightened, progressive management of the wider freshwater resource. As part of this account, attempts are made to clarify the relationship between key biodiversity-related policy drivers in the freshwater environment, and to explain how the spectre of climate change can be addressed within designated site management. The importance of strategic freshwater science, collaboratively designed and funded, in maximising the value of the designated freshwater site network to the wider freshwater habitat resource, is stressed.