9 resultados para Leave entitlements

em Aquatic Commons


Relevância:

10.00% 10.00%

Publicador:

Resumo:

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.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Almost 120 days at sea aboard three NOAA research vessels and one fishing vessel over the past three years have supported biogeographic characterization of Tortugas Ecological Reserve (TER). This work initiated measurement of post-implementation effects of TER as a refuge for exploited species. In Tortugas South, seafloor transect surveys were conducted using divers, towed operated vehicles (TOV), remotely operated vehicles (ROV), various sonar platforms, and the Deepworker manned submersible. ARGOS drifter releases, satellite imagery, ichthyoplankton surveys, sea surface temperature, and diver census were combined to elucidate potential dispersal of fish spawning in this environment. Surveys are being compiled into a GIS to allow resource managers to gauge benthic resource status and distribution. Drifter studies have determined that within the ~ 30 days of larval life stage for fishes spawning at Tortugas South, larvae could reach as far downstream as Tampa Bay on the west Florida coast and Cape Canaveral on the east coast. Together with actual fish surveys and water mass delineation, this work demonstrates that the refuge status of this area endows it with tremendous downstream spillover and larval export potential for Florida reef habitats and promotes the maintenance of their fish communities. In Tortugas North, 30 randomly selected, permanent stations were established. Five stations were assigned to each of the following six areas: within Dry Tortugas National Park, falling north of the prevailing currents (Park North); within Dry Tortugas National Park, falling south of the prevailing currents (Park South); within the Ecological Reserve falling north of the prevailing currents (Reserve North); within the Ecological Reserve falling south of the prevailing currents (Reserve South); within areas immediately adjacent to these two strata, falling north of the prevailing currents (Out North); and within areas immediately adjacent to these two strata, falling south of the prevailing currents (Out South). Intensive characterization of these sites was conducted using multiple sonar techniques, TOV, ROV, diver-based digital video collection, diver-based fish census, towed fish capture, sediment particle-size, benthic chlorophyll analyses, and stable isotope analyses of primary producers, fish, and, shellfish. In order to complement and extend information from studies focused on the coral reef, we have targeted the ecotone between the reef and adjacent, non-reef habitats as these areas are well-known in ecology for indicating changes in trophic relationships at the ecosystem scale. Such trophic changes are hypothesized to occur as top-down control of the system grows with protection of piscivorous fishes. Preliminary isotope data, in conjunction with our prior results from the west Florida shelf, suggest that the shallow water benthic habitats surrounding the coral reefs of TER will prove to be the source of a significant amount of the primary production ultimately fueling fish production throughout TER and downstream throughout the range of larval fish dispersal. Therefore, the status and influence of the previously neglected, non-reef habitat within the refuge (comprising ~70% of TER) appears to be intimately tied to the health of the coral reef community proper. These data, collected in a biogeographic context, employing an integrated Before-After Control Impact design at multiple spatial scales, leave us poised to document and quantify the postimplementation effects of TER. Combined with the work at Tortugas South, this project represents a multi-disciplinary effort of sometimes disparate disciplines (fishery oceanography, benthic ecology, food web analysis, remote sensing/geography/landscape ecology, and resource management) and approaches (physical, biological, ecological). We expect the continuation of this effort to yield critical information for the management of TER and the evaluation of protected areas as a refuge for exploited species. (PDF contains 32 pages.)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The foundation of Habermas's argument, a leading critical theorist, lies in the unequal distribution of wealth across society. He states that in an advanced capitalist society, the possibility of a crisis has shifted from the economic and political spheres to the legitimation system. Legitimation crises increase the more government intervenes into the economy (market) and the "simultaneous political enfranchisement of almost the entire adult population" (Holub, 1991, p. 88). The reason for this increase is because policymakers in advanced capitalist democracies are caught between conflicting imperatives: they are expected to serve the interests of their nation as a whole, but they must prop up an economic system that benefits the wealthy at the expense of most workers and the environment. Habermas argues that the driving force in history is an expectation, built into the nature of language, that norms, laws, and institutions will serve the interests of the entire population and not just those of a special group. In his view, policy makers in capitalist societies are having to fend off this expectation by simultaneously correcting some of the inequities of the market, denying that they have control over people's economic circumstances, and defending the market as an equitable allocator of income. (deHaven-Smith, 1988, p. 14). Critical theory suggests that this contradiction will be reflected in Everglades policy by communicative narratives that suppress and conceal tensions between environmental and economic priorities. Habermas’ Legitimation Crisis states that political actors use various symbols, ideologies, narratives, and language to engage the public and avoid a legitimation crisis. These influences not only manipulate the general population into desiring what has been manufactured for them, but also leave them feeling unfulfilled and alienated. Also known as false reconciliation, the public's view of society as rational, and "conductive to human freedom and happiness" is altered to become deeply irrational and an obstacle to the desired freedom and happiness (Finlayson, 2005, p. 5). These obstacles and irrationalities give rise to potential crises in the society. Government's increasing involvement in Everglades under advanced capitalism leads to Habermas's four crises: economic/environmental, rationality, legitimation, and motivation. These crises are occurring simultaneously, work in conjunction with each other, and arise when a principle of organization is challenged by increased production needs (deHaven-Smith, 1988). Habermas states that governments use narratives in an attempt to rationalize, legitimize, obscure, and conceal its actions under advanced capitalism. Although there have been many narratives told throughout the history of the Everglades (such as the Everglades was a wilderness that was valued as a wasteland in its natural state), the most recent narrative, “Everglades Restoration”, is the focus of this paper.(PDF contains 4 pages)

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The individuals studied came from commercial catches on the coastal area off Mar del Plata. The monthly distribution of sizes shows that the juvenile stay in coastal waters, while the adult individuals leave those waters during winter season to return there in the spring during the season of sexual maturation and spawning, when the water reaches temperature of 10-11°C. The jack mackerel is a relatively small fish, compared with other species of its genus, and has a total length of scarcely 25 cm. The comparison of indexes and mesurements does not reveal any marked difference between sexes, except for the total length, which is greater in the females. Sexually nature individuals at a lenth of 13 cm have been found. Spawning takes place in coastal waters. A great part of the population spawns from December to January. There are oscillations ranging from November to March. On this latter month mature individuals of smaller size have veen found. The jack mackerel feeds usually on copepods and other planktonic organims, but it can feed also on juveniles of other fishes. This fish is caught throghout the whole year. The catches show their greater peak during winter; one other non-constant peak occurs during the spring (October-November) and declines shoraply during the summer months. It follows from this that the time of greates catch does not coincide with spawning season, or with the appearence of the greatest mean sizes. This happens because the interests of the fishermen are attracted during those months by others species of greater commercial value.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Spawning of bonga (Ethmalosa fimbriata Bowdich) takes place in polyhalin waters (Sppt. > 5ppt.). Migrations of young fish were studied by the mean of length data observed in different points of the lagoon from the artisanal fishery. Bonga remain 4 months in the hatchery (6 cm), before they expand in the whole lagoon until the age of 9/10 months. After this expansion phase, the fishes come back to the spawning fields (spawning length: 14/15 cm). Postspawning fishes leave the lagoon. Between birth and spawning, bonga are not affected by salinity changes, but reproduction occurs only in waters where salinity is higher than 5ppt.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Distribution, movements, and habitat use of small (<46 cm, juveniles and individuals of unknown maturity) striped bass (Morone saxatilis) were investigated with multiple techniques and at multiple spatial scales (surveys and tag-recapture in the estuary and ocean, and telemetry in the estuary) over multiple years to determine the frequency and duration of use of non-natal estuaries. These unique comparisons suggest, at least in New Jersey, that smaller individuals (<20 cm) may disperse from natal estuaries and arrive in non-natal estuaries early in life and take up residence for several years. During this period of estuarine residence, individuals spend all seasons primarily in the low salinity portions of the estuary. At larger sizes, they then leave these non-natal estuaries to begin coastal migrations with those individuals from nurseries in natal estuaries. These composite observations of frequency and duration of habitat use indicate that non-natal estuaries may provide important habitat for a portion of the striped bass population.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Skates (family Rajidae) are oviparous and lay tough, thick-walled eggs. At least some skate species lay their eggs in spatially restricted nursery grounds where embryos develop and hatch (Hitz, 1964; Hoff, 2007). After hatching, neonates may quickly leave the nursery grounds (Hoff, 2007). Egg densities in these small areas may be quite high. As an example, in the eastern Bering Sea, a site <2 km2 harbored eggs of Alaska skate (Bathyraja parmifera) exceeding 500,000/km2. All skate nursery grounds have been identified over soft sea floors (Lucifora and García, 2004; Hoff, 2007).

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An experiment was undertaken to determine from which part of silver belly (Leiognathus splendens) carcasses originate the autolytic enzymes responsible for liquefaction of silage. Findings show that it is important to leave head and viscera present in order to get a satisfactory liquefaction in silage prepared from silver belly using 3.5% formic acid. The storage life of silage produced from various parts of the fish carcasses is also discussed.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

One of the most important marine ecological phenomena is red tide which is created by increasing of phytoplankton population, influenced by different factors such as climate condition changes, utrification hydrological factors and can leave sever and undesired ecological and economical effects behind itself in the case of durability. Coast line of Hormozgan is about 900km from east to west, within the range of geographical coordinates of 56 16 23.8, 26 58 8.8 to 54 34 5.33 and 26 34 32 eastern longitude and northern latitude, seven sampling stations were considered and sampled for a period of one year from October 2008 to October 2009. after the analysis of Satellite images, monthly, during the best time. In several stages, samplings were performed. In each station, three samples were collected for identification and determination of Bloom- creating species abundance. Cochlodinium polykrikoides was the species responsible for the discoloration which occurred at October 2008 in Hormozgan marine water. Environmental parameters such as sea surface temperature, pH, salinity, Dissolved Oxygen concentration, Total Dissolved Solids (T.D.S.), conductivity, nitrate, nitrite and phosphate and also chlorophyll a were measured and calculated. Kruscal Wallis test was used to compare the densities between different months, seasons and the studied stations. Mann-whitney test from Nonparametric Tests was used for couple comparison. Pearson correlation coefficient was used to determine the relationship between physical and chemical data set and the abundance of Cochlodinium polykrikoides. Multivariate Regression and analysis of variance (ANOVA) also were used to obtain the models and equations of red tide occurrence relationship, environmental parameters and nutrient data. The highest density was 26 million cells per liter in Qeshm station. A meaningful difference was observed between sampling months and seasons but there was no between sampling stations which indicates that in favorable conditions, the occurrence of this phenomenon by the studied species is probable. Regarding to β coefficients of nitrate, temperature, phosphate, Total Dissolvable Solutions (T.D.S) and pH these parameters are effective on the abundance of this species and red tide occurrence. Increase in these factors can represent the effects and outcomes of human activities and increase in marine pollution.