Bibliografía argentina de peces de agua dulce.

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.)

Introducción de peces exóticos en la República Argentina

A review and analysis of the exotic fish distribution and introduction is made using bibliographic information. Both lentic and lotic environments were considered. In order to classify the state of the populations, different categories were defined as follow: permanent, probably permanent, reported and unknown. Results show that 15 species were attempted to be introduced from 1904. Only 8 of them arose an successfull aclimatization: raimbow trout, brown trout, lake trout, landlocked salmon, carp, goldfish, and mosquitofish. For the salmonids, ecological features were analized, in order to explain the disappearence or the permanence in some regions. (Document contains 90 pages)

The role of sites of special scientific interest (SSSIs) in the conservation of British rivers

This paper discusses the particular contribution of the SSSI (Sites of Special Scientific Interest) as a way of nature conservation for rivers. In 1989, the Nature Conservancy Council proposed a dual selection system for selection of rivers; either (1) "Whole river" SSSIs representing the main types of river, or rivers which show classic and representative transitions down their lengths, or (2) "Sectional" SSSIs which are shorter stretches of river with high nature conservation interest. The NCC has recently classified all SSSIs with a river interest into 4 categories: - river SSSIs, river valley SSSIs, river adds interest - where the river clearly adds biological interest to the site, and rivers of incidental interest. The overall length of river SSSIs amounts to almost 1000 km.

Testable models of aquatic systems: A NERC special topic for integrating experiments and modelling

A major part of the support for fundamental research on aquatic ecosystems continues to be provided by the Natural Environment Research Council (NERC). Funds are released for ”thematic” studies in a selected special topic or programme. ”Testable Models of Aquatic Ecosystems” was a Special Topic of the NERC, initiated in 1995, the aim of which was to promote ecological modelling by making new links between experimental aquatic biologists and state-of-the-art modellers. The Topic covered both marine and freshwater systems. This paper summarises projects on aspects of the responses of individual organisms to the effects of environmental variability, on the assembly, permanence and resilience of communities, and on aspects of spatial models. The authors conclude that the NERC Special Topic has been highly successful in promoting the development and application of models, most particularly through the interplay between experimental ecologists and formal modellers.

Determination of dissolved oxygen in water with leukoberbelin-blue I. A quick Winkler method. [Translation from: Z.analyt.Chem. 262 97-99, 1972.]

The reaction of Mn(II) with water-dissolved oxygen, to a higher manganese hydroxide in an alkaline medium, as with the longstanding classic Winkler method, is the first step in the method described here. The assumption for faultless results by the conventional and modified Winkler method is clean water, which contains no organic substances by Mn(III) or Mn(IV). In many cases, however, eg. in river and lake-water tests, it can be seen with the naked eye that after some time the originally brown-coloured precipitate of manganese hydroxide becomes more and more colourless. Oxygen content was analysed in the water samples and evaluated by raising the amount of the leuko-base and giving the corresponding dilution of the colouring matter solution formed still higher oxygen contents can be measured.

Perspectives from agriculture: advances in livestock breeding - implications for aquaculture genetics

In this paper we present livestock breeding developments that could be taken into consideration in the genetic improvement of farmed aquaculture species, especially in freshwater fish. Firstly, the current breeding objective in aquatic species has focused almost exclusively on the improvement of body weight at harvest or on growth related traits. This is unlikely to be sufficient to meet the future needs of the aquaculture industry. To meet future demands breeding programs will most likely have to include additional traits, such as fitness related ones (survival, disease resistance), feed efficiency, or flesh quality, rather than only growth performance. In order to select for a multi-trait breeding objective, genetic variation in traits of interest and the genetic relationships among them need to be estimated. In addition, economic values for these traits will be required. Generally, there is a paucity of data on variable and fixed production costs in aquaculture, and this could be a major constraint in the further expansion of the breeding objectives. Secondly, genetic evaluation systems using the restricted maximum likelihood method (REML) and best linear unbiased prediction (BLUP) in a framework of mixed model methodology could be widely adopted to replace the more commonly used method of mass selection based on phenotypic performance. The BLUP method increases the accuracy of selection and also allows the management of inbreeding and estimation of genetic trends. BLUP is an improvement over the classic selection index approach, which was used in the success story of the genetically improved farmed tilapia (GIFT) in the Philippines, with genetic gains from 10 to 20 per cent per generation of selection. In parallel with BLUP, optimal genetic contribution theory can be applied to maximize genetic gain while constraining inbreeding in the long run in selection programs. Thirdly, by using advanced statistical methods, genetic selection can be carried out not only at the nucleus level but also in lower tiers of the pyramid breeding structure. Large scale across population genetic evaluation through genetic connectedness using cryopreserved sperm enables the comparison and ranking of genetic merit of all animals across populations, countries or years, and thus the genetically superior brood stock can be identified and widely used and exchanged to increase the rate of genetic progress in the population as a whole. It is concluded that sound genetic programs need to be established for aquaculture species. In addition to being very effective, fully pedigreed breeding programs would also enable the exploration of possibilities of integrating molecular markers (e.g., genetic tagging using DNA fingerprinting, marker (gene) assisted selection) and reproductive technologies such as in-vitro fertilization using cryopreserved spermatozoa.

Pacific Hake, Merluccius productus, Autecology: A Timely Review

Pacific hake, Merluccius productus, the most abundant groundfish in the California Current Large Marine Ecosystem (CCLME), is a species of both commercial significance, supporting a large international fishery, and ecological importance, connecting other species as both predator and prey. Coastal Pacific hake migrations are characterized by movements between northern summer feeding areas and southern winter spawning areas, with variations in annual abundance, distribution, and the extent of these movements associated with varying climate-ocean conditions. In general, warm (cool) years with enhanced (reduced) stratification and poleward (equatorward) transport are often related to good (poor) recruitment, increased (decreased) northward distribution, and reduced (enhanced) growth. However, the classic periodic pattern of annual migration and distribution may no longer be fully representative. Based on recent advances in the understanding of climate-ocean variability off the U.S. west coast, we hypothesize that the annual movements of Pacific hake are more responsive to climate-ocean variability than previously thought, and further, that changes observed in Pacific hake distributions may reflect long-term changes in climate-ocean conditions in the CCLME. Therefore, an updated model of these relations is key to effective monitoring and management of this stock, as well as to devising scenarios of future change in the CCLME as a result of climate variations. The current state of knowledge of the relationship between the Pacific hake and its environment is reviewed, highlighting emerging ideas compared to those of the past, and priorities for future research are suggested.

The History and Literature of America's Oysters

Historically, America's use and enjoyment of the oyster extend far back into prehistoric times. The Native Americans often utilized oysters, more intensively in some areas than in others, and, at least in some areas of the Caribbean and Pacific coast, the invading Spanish sought oysters as eagerly as they did gold-but for the pearls. That was the pearl oyster, Pinctada sp., and signs of its local overexploitation were recorded early in the 16th century. During the 1800's, use of the eastern oyster grew phenomenally and, for a time, it outranked beef as a source of protein in some parts of the nation. Social events grew up around it, as it became an important aspect of culture and myth. Eventually, research on the oyster began to blossom, and scientific literature on the various species likewise bloomed-to the extent that when the late Paul Galtsoff wrote his classic treatise "The American oyster Crassostrea virginica Gmelin" in 1954, he reported compiling an extensive bibliography of over 6,000 subject and author cards on oysters and related subjects which he deposited in the library of the Woods Hole Laboratory of the Bureau of Commercial Fisheries (now NMFS). That large report, volume 64 (480 pages) of the agency's Fishery Bulletin, was a bargain at $2.75, and it has been a standard reference ever since. But the research and the attendant literature have grown greatly since Galtsoff's work was published, and now that has been thoroughly updated.

Management of water hyacinth, Eichhornia crassipes, in Lake Victoria Basin

Water hyacinth is a free-floating waterweed native to the Amazon River Basin in South America. In its native range, water hyacinth is not an environmental problem, although the weed is one of the most invasive alien plants in freshwater environments. Water hyacinth has the potential to become invasive through fast vegetative reproduction and rapid growth to accumulate huge biomass and extensive cover in freshwater environments. Over the last 150 years water hyacinth has invaded most countries in the tropics and sub-tropics, introduced by man, mainly for ornamental purposes. Such introductions led to the infestation of most freshwater-ways in the southern United States of America, parts of Australia, the pacific islands, and most countries in Asia and Africa. The extensive tightly packed mats of water hyacinth are often associated with devastating socio-economic and environmental impacts. Invasion by the weed has, therefore, often generated urgent costly problems associated with the weed biomass and its management. A classic example of such problems was triggered by the invasion and proliferation of water hyacinth in the Lake Victoria Basin during the 1980s (Freilink 1989, Taylor 1993, Twongo et al., 1995). The weed infestation marked the beginning of a decade of intensive and systematic campaign by the three riparian states (Kenya, Tanzania and Uganda) to bring weed proliferation under control. The discussions in this Chapter span over ten years of dealing with the challenges paused by the imperative to manage infestations of water hyacinth in the Lake Victoria Basin. The challenges included the need to understand the dynamics of water hyacinth infestation; its distribution, proliferation and impact modalities; and the development and implementation of appropriate weed control strategies and options. Most specific examples were taken from the Ugandan experience (NARO, 2002).