102 resultados para invertebrate


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This is the River Dart Biological Survey from 10th June to 15th July 1968 by the Devon River Authority. This survey was undertaken to investigate the invertebrate bottom fauna of the river and to assess the condition of the river with regard to pollution. It describes the environmental conditions of the River Dart and the biological sampling method used, plus a brief conclusion of the survey. It also contains tables with the different species present and abundance on each sampling stations.

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This is the Evaluation of the impact of cypermethrin use in forestry on Welsh streams from the University of Plymouth, published on September 2010 by the Environment Agency South West. The report focuses attention on Cypermethrin, a highly active synthetic pyrethroid insecticide effective against a wide range of pests in agriculture, public health, and animal husbandry. It is also used in forestry to control the pine weevil, Hylobius abietis. Cypermethrin is very toxic to aquatic invertebrates and fish at nanogram per litre concentrations. This project checks the effectiveness of current best practice measures in minimising the risk of pollution associated with the use of cypermethrin in forestry in Wales. Chemical results from the intensive studies show that cypermethrin entered minor watercourses draining treated areas at two of the eight sites. In one of these cases the level was well in excess of the short-term Predicted No Effect Concentration. The absence of a buffer area at the other site resulted in the cypermethrin reaching a main drain. However dilution appeared to be sufficient to prevent any impact on water quality or on the invertebrate community in the main stream. Invertebrate and chemical data from the extensive survey showed little evidence of pollution due to wider use of cypermethrin in Welsh forestry. Finally, a number of recommendations are made for further tightening controls on forestry practice to minimise the risk of cypermethrin entering the aquatic environment.

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This is the Cheshire stillwaters. Summary results of 1997 data Oak Mere, Betley Mere and Marbury Big from the National Rivers Authority, June 1998. In May 1997, a Stillwaters meeting was held to discuss the way forward in stillwaters monitoring. It decided upon the establishment of a three year rolling programme, in which three stillwaters would be monitored three times a year, every third year. The stillwaters where chosen due to water quality (i.e potential polluted / sensitive waters), fisheries and ecological interests. The Still waters chosen for the first year (1997) were Oak Mere, Betley Mere and Marbury Big Mere. The surveys were aimed to produce a comprehensive study of the still water through monitoring a variety of parameters. Algal, zooplankton and water chemical samples were taken three times a year, (April, July and September). In addition, fisheries surveys were taken in July and marginal invertebrate surveys taken in September.

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This is the Stillwaters monitoring programme summary results 2000 from the Environment Agency. In May 1997, a Stillwaters meeting was held to discuss the way forward in stillwaters monitoring. It decided upon the establishment of a three year rolling programme, in which three stillwaters would be monitored three times a year, every third year. During 2000, stillwaters monitored for the fourth year of the Stillwaters Monitoring Programme were Hatch Mere, Marbury Big Mere, Comber Mere, Tabley Mere, Tatton Mere and Melchett Mere. Algal, zooplankton and water chemical samples were taken on all meres. Surveys of Tabley Mere and Comber Mere continued on from last year when water quality concerns were highlighted. Continuous monitoring in Oak Mere, including water level data continued in 2000. Fish surveys were carried out in Tatton Mere and Comber Mere. Tabley Mere survey was abandoned due to the awkward bathymetry of the mere. No invertebrate samples were taken in 2000 due to lack of resources.

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This is the Cheshire stillwaters summary results 1999 from the Environment Agency North West. In May 1997, a Stillwaters meeting was held to discuss the way forward in stillwaters monitoring. It decided upon the establishment of a three year rolling programme, in which three stillwaters would be monitored three times a year, every third year. During 1999, stillwaters monitored for the third year of the Stillwaters Monitoring Programme were Tabley Mere, Comber Mere and Norbury Mere. Surveys of Petty Pool and Betley Mere continued for a second and third year respectively after water quality concerns were highlighted in previous end-of-year reports. Oak Mere was also surveyed for the third year running due to its unusual ecology. This year, the variety of parameters monitored was limited to algal, zooplankton and water chemical samples. Fisheries and marginal invertebrate surveys were not completed due to lack of resources.

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This is the episodic variations in stream water chemistry associated with acid rainfall and run-off and the effect on aquatic ecosystems, with particular reference to fish populations in North West England produced by the North West Water Authority in 1985. This report looks at the biological, physical and chemical information collected over a five year period from over 100 sites on upland streams in the North West Region of which drained rocks of low buffering capacity. In both Lake District and South Pennine sites striking differences were found between the composition of invertebrate communities inhabiting acid-stressed and less acid-stressed streams. Electric fishing surveys showed that acidic streams (geometric mean pH <5.5) generally had abnormally low densities of salmonids ( < 0 .2m2) and that 0+ fish were very few or absent. The latter indicates recruitment failure. Salmon were more sensitive than trout to low pH.

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This is the Report of 1996 survey of Trout Beck with particular reference to spawning gravel quality and invertebrates as a food source for salmonids produced by the Environment Agency North West. Whilst the main River Derwent is quite a high profile salmon fishery, Trout Beck is not a significant fishery in its own right, but serves to maintain the genetic integrity of the wild populations of trout and salmon in the catchment by providing a unique habitat. This survey addressed the invertebrate food availability, and additionally looked at the substrate to try to determine whether the bed type might actually be unsuitable for spawning, especially in view of the previously mentioned silt inputs.

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This is the Acid rain project biosurveys of streams in the Wastwater catchment produced by the North West Water Authority in 1985. This report forms part of a series on component biological investigations, identified by location or topic, within the acid rain project. Reporting of the Wastwater catchment data would not have been given priority ordinarily, but it has been brought forward to coincide with J. Robinson's reporting of his investigations of land use and liming in the catchment. This report shows water chemistry results of a violent rainstorms such pH, alkalinity, Mg, Ca and Al. Moreover it shows invertebrate, fish and chemical data for Wastwater catchment sites.

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The study here reported is a survey of the most common non-parasitic nematode families of Chesapeake Bay, Maryland, with descriptions and figures, so that ecological workers and students of invertebrate zoology may be encouraged not to pass over this highly interesting and abundant invertebrate phylum. This survey is not a complete account of the free-living nematode population of the Bay, however, since only the middle section of the Bay was sampled and since the collections were not made systematically throughout the year. The physical and chemical factors of Chesapeake Bay may be found in several publications of the Chesapeake Biological Laboratory, Solomons Island, Maryland, and in the records of the Chesapeake Bay Institute, Annapolis, Maryland.

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Piscivorous fishes, many of which are economically valuable, play an important role in marine ecosystems and have the potential to affect fish and invertebrate populations at lower trophic levels. Therefore, a quantitative understanding of the foraging ecology of piscivores is needed for ecosystem-based fishery management plans to be successful. Abundance and stomach contents of seasonally co-occurring piscivores were examined to determine overlap in resource use for Summer Flounder (Paralichthys dentatus; 206–670 mm total length [TL]), Weakfish (Cynoscion regalis; 80–565 mm TL), Bluefish (Pomatomus saltatrix; 55–732 mm fork length [FL]), and Striped Bass (Morone saxatilis; 422–920 mm FL). We collected samples from monthly, fishery-independent trawl surveys conducted on the inner continental shelf (5–27 m) off New Jersey from June to October 2005. Fish abundances and overlaps in diet and habitat varied over this study period. A wide range of fish and invertebrate prey was consumed by each species. Diet composition (determined from 1997 stomachs with identifiable contents) varied with ontogeny (size) and indicated limited overlap between most of the species size classes examined. Although many prey categories were shared by the piscivores examined, different temporal and spatial patterns in habitat use seemed to alleviate potential competition for prey. Nevertheless, the degree of overlap in both fish distributions and diets increased severalfold in the fall as species left estuaries and migrated across and along the study area. Therefore, the transitional period of fall migration, when fish densities are higher than at other times of the year, may be critical for unraveling resource overlap for these seasonally migrant predators.

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The priority management goal of the National Marine Sanctuaries Program (NMSP) is to protect marine ecosystems and biodiversity. This goal requires an understanding of broad-scale ecological relationships and linkages between marine resources and physical oceanography to support an ecosystem management approach. The Channel Islands National Marine Sanctuary (CINMS) is currently reviewing its management plan and investigating boundary expansion. A management plan study area (henceforth, Study Area) was described that extends from the current boundary north to the mainland, and extends north to Point Sal and south to Point Dume. Six additional boundary concepts were developed that vary in area and include the majority of the Study Area. The NMSP and CINMS partnered with NOAA’s National Centers for Coastal Ocean Science Biogeography Team to conduct a biogeographic assessment to characterize marine resources and oceanographic patterns within and adjacent to the sanctuary. This assessment includes a suite of quantitative spatial and statistical analyses that characterize biological and oceanographic patterns in the marine region from Point Sal to the U.S.-Mexico border. These data were analyzed using an index which evaluates an ecological “cost-benefit” within the proposed boundary concepts and the Study Area. The sanctuary resides in a dynamic setting where two oceanographic regimes meet. Cold northern waters mix with warm southern waters around the Channel Islands creating an area of transition that strongly influences the regions oceanography. In turn, these processes drive the biological distributions within the region. This assessment analyzes bathymetry, benthic substrate, bathymetric life-zones, sea surface temperature, primary production, currents, submerged aquatic vegetation, and kelp in the context of broad-scale patterns and relative to the proposed boundary concepts and the Study Area. Boundary cost-benefit results for these parameters were variable due to their dynamic nature; however, when analyzed in composite the Study Area and Boundary Concept 2 were considered the most favorable. Biological data were collected from numerous resource agencies and university scientists for this assessment. Fish and invertebrate trawl data were used to characterize community structure. Habitat suitability models were developed for 15 species of macroinvertebrates and 11 species of fish that have significant ecological, commercial, or recreational importance in the region and general patterns of ichthyoplankton distribution are described. Six surveys of ship and plane at-sea surveys were used to model marine bird diversity from Point Arena to the U.S.-Mexico border. Additional surveys were utilized to estimate density and colony counts for nine bird species. Critical habitat for western snowy plover and the location of California least tern breeding pairs were also analyzed. At-sea surveys were also used to describe the distribution of 14 species of cetaceans and five species of pinnipeds. Boundary concept cost-benefit indices revealed that Boundary Concept 2 and the Study Area were most favorable for the majority of the species-specific analyses. Boundary Concept 3 was most favorable for bird diversity across the region. Inadequate spatial resolution for fish and invertebrate community data and incompatible sampling effort information for bird and mammal data precluded boundary cost-benefit analysis.

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Creel and trawl surveys of Biscayne Bay were carried out in 1982-1983 to assess commercial fish and macro-invertebrate habitats and fisheries. Dredged and/or barren bottom was dramatically less productive than seagrass, algae or hard bottom areas. Low fish abundance and diversity in north Biscayne Bay appeared to be correlated with high turbidity and low seagrass abundance. Substantive increases in fish and crustacean productivity in north Biscayne Bay will occur only if seagrass communities can be re-established. Deeper dredged areas in North Bay will not likely become recolonized with seagrass even if turbidity levels are reduced. Hard bottom areas in South Bay are associated with high diversity of fish fauna and serve as nursery areas for several highly desirable species (e.g. hogfish, yellowtail snapper, lane snapper). The area between Julia Tuttle and 79th Street Causeways, which had very dense seagrass abundance, was the richest area on either North or South Biscayne Bay for juvenile fish and shrimp. This basin can serve as a model for the potential of the remainder of North Bay.

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The Deepwater Horizon (DWH) accident in the northern Gulf of Mexico occurred on April 20, 2010 at a water depth of 1525 meters, and a deep-sea plume was detected within one month. Oil contacted and persisted in parts of the bottom of the deep-sea in the Gulf of Mexico. As part of the response to the accident, monitoring cruises were deployed in fall 2010 to measure potential impacts on the two main soft-bottom benthic invertebrate groups: macrofauna and meiofauna. Sediment was collected using a multicorer so that samples for chemical, physical and biological analyses could be taken simultaneously and analyzed using multivariate methods. The footprint of the oil spill was identified by creating a new variable with principal components analysis where the first factor was indicative of the oil spill impacts and this new variable mapped in a geographic information system to identify the area of the oil spill footprint. The most severe relative reduction of faunal abundance and diversity extended to 3 km from the wellhead in all directions covering an area about 24 km2. Moderate impacts were observed up to 17 km towards the southwest and 8.5 km towards the northeast of the wellhead, covering an area 148 km2. Benthic effects were correlated to total petroleum hydrocarbon, polycyclic aromatic hydrocarbons and barium concentrations, and distance to the wellhead; but not distance to hydrocarbon seeps. Thus, benthic effects are more likely due to the oil spill, and not natural hydrocarbon seepage. Recovery rates in the deep sea are likely to be slow, on the order of decades or longer.

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The Monitor National Marine Sanctuary (MNMS) was the nation’s first sanctuary, originally established in 1975 to protect the famous civil war ironclad shipwreck, the USS Monitor. Since 2008, sanctuary sponsored archeological research has branched out to include historically significant U-boats and World War II shipwrecks within the larger Graveyard of the Atlantic off the coast of North Carolina. These shipwrecks are not only important for their cultural value, but also as habitat for a wide diversity of fishes, invertebrates and algal species. Additionally, due to their unique location within an important area for biological productivity, the sanctuary and other culturally valuable shipwrecks within the Graveyard of the Atlantic are potential sites for examining community change. For this reason, from June 8-30, 2010, biological and ecological investigations were conducted at four World War II shipwrecks (Keshena, City of Atlanta, Dixie Arrow, EM Clark), as part of the MNMS 2010 Battle of the Atlantic (BOTA) research project. At each shipwreck site, fish community surveys were conducted and benthic photo-quadrats were collected to characterize the mobile conspicuous fish, smaller prey fish, and sessile invertebrate and algal communities. In addition, temperature sensors were placed at all four shipwrecks previously mentioned, as well as an additional shipwreck, the Manuela. The data, which establishes a baseline condition to use in future assessments, suggest strong differences in both the fish and benthic communities among the surveyed shipwrecks based on the oceanographic zone (depth). In order to establish these shipwrecks as sites for detecting community change it is suggested that a subset of locations across the shelf be selected and repeatedly sampled over time. In order to reduce variability within sites for both the benthic and fish communities, a significant number of surveys should be conducted at each location. This sampling strategy will account for the natural differences in community structure that exist across the shelf due to the oceanographic regime, and allow robust statistical analyses of community differences over time.

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Coastal ecosystems and the services they provide are adversely affected by a wide variety of human activities. In particular, seagrass meadows are negatively affected by impacts accruing from the billion or more people who live within 50 km of them. Seagrass meadows provide important ecosystem services, including an estimated $1.9 trillion per year in the form of nutrient cycling; an order of magnitude enhancement of coral reef fish productivity; a habitat for thousands of fish, bird, and invertebrate species; and a major food source for endangered dugong, manatee, and green turtle. Although individual impacts from coastal development, degraded water quality, and climate change have been documented, there has been no quantitative global assessment of seagrass loss until now. Our comprehensive global assessment of 215 studies found that seagrasses have been disappearing at a rate of 110 square kilometers per year since 1980 and that 29% of the known areal extent has disappeared since seagrass areas were initially recorded in 1879. Furthermore, rates of decline have accelerated from a median of 0.9% per year before 1940 to 7% per year since 1990. Seagrass loss rates are comparable to those reported for mangroves, coral reefs, and tropical rainforests and place seagrass meadows among the most threatened ecosystems on earth.