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47 Uppsatser om Freshwater pearl mussel - Sida 1 av 4

Freshwater pearl mussel as indicators of Swedish streams - a comparison between freshwater pearl mussel and biological quality elements

The Freshwater pearl mussel (Margaritifera margaritifera) is a large freshwater mussel. Because of its sensitivity to human impact, such as eutrophication, acidification and alterations of hydromorphology, the species is considered as a robust indicator of stream water quality and biodiversity. Moreover, due to the species complex life cycle, including a larval stage on the gills of salmon and trout, and sensitivity of early life stages, regeneration is often used as an indicator. The Freshwater pearl mussel is also used in the expert judgement of status classification of benthic invertebrates according to the European Water Framework Directive. The purpose of this study was to gain a deeper understanding of the Freshwater pearl mussel as an indicator for Swedish streams. It was made with two types of association analyses.

Bottensubstratets inverkan på föryngring av Flodpärlmussla

The Freshwater pearl mussel (Margaritifera margaritifera) is threatened throughout its range. There has been a substantial decline of the species and one major reason is habitat degradation. We investigated how the substrate composition of the bottom floor affects the regeneration of the mussel by analyzing data from the Västerbotten County Board?s inventory of the Freshwater pearl mussel. The results implied that fine material such as fine sediment and sand might be detrimental to regeneration whereas gravel and boulders and in particular stone seem to be beneficial.

Inventering av flodpärlmussla i Fylleån norr om Gyltigesjön

Freshwater environments are threatened worldwide, of which many of the species associatedwith freshwater. In 2014, 243 freshwater mussels were on the international Red List. One ofthem is the Freshwater pearl mussel, Margaritifera margaritifera, which because of itscomplex life cycle can be counted as an indicator of whether a stream is worth protecting. It's since the early 1900's in decline throughout their range. Sweden is counted as a core area which is why we have not only a national but an international responsibility to conserve the species.

Flodpärlmusslans status i Laxtjärnbäcken : Effekter på flodpärlmusslan av sedimentbelastning och förekomst av bäckröding

The aim of this present study was to determine and evaluate whether the presence of brooktrout (Salvelinus fontinalis) and sediment load may be a threat against the reproduction anddistribution of Freshwater pearl mussel (Margaritifera margaritifera) in a creek located innorthern Sweden. Freshwater pearl mussel is an endangered species and is dependent ofbrown trout (Salmo trutta) to reproduce. Therefore there are concerns of indirect effects onthe population of pearl mussel by competition between brown trout and brook trout. Ditchesfrom a nearby gravel road have been fixed to lower the sediment load into the creek. I tried toevaluate this action plan.

Bottensedimentets betydelse för flodpärlmusslans föryngring ? en metodutveckling

The Freshwater pearl mussel Margaritifera margaritifera is an endangered species. To survive, the young mussels demand a fairly coarse bottom material containing an appropriate quantity of organic substrate to survive without suffocating. In order to estimate if a bottom is suitable for juvenile mussels, samples of the sediment are needed. To obtain samples a sampling device called the Mulv collector has been developed within this project. Bottom samples were collected from 18 stations in 4 south Swedish streams, Vramsån, Kling-storpsbäcken, Brönnestadsån and Bräkneån.

Rondellen och dess växtmaterial

Common species of freshwater mussels may, like the Freshwater pearl mussel (Margaritifera margaritifera) have a drastic decline in number and there is several reasons, like sedimentation, a decline of host fishes, introduction of alien species, nutrition leakages from agriculture and pollutants of medic drugs and poison. Ann Gustavsson made in the year of 2007 a study over rejuventation of freshwater great mussels in nine watersystems and considered that the rejuventation within the populations were all along the line poor. This study orients from her work and points to determine if there is a connection between the poor juventation and pollution of nitrogen and phosphorous from industries and private sanitations. The study was performed with the software program ArcGIS9.2 to take out drainage areas for the concerned habitats and contact was made with the concerned authoritys. When it comes to supervision of private sanitations is it the countys and for industries is it the county administrative board.

Finns det något samband mellan stormusslors (unionoida) föryngring och utsläpp i närheten av dess levnadsmiljö? : en jämförelse mellan vattendrag i Västra Götaland

Common species of freshwater mussels may, like the Freshwater pearl mussel (Margaritifera margaritifera) have a drastic decline in number and there is several reasons, like sedimentation, a decline of host fishes, introduction of alien species, nutrition leakages from agriculture and pollutants of medic drugs and poison. Ann Gustavsson made in the year of 2007 a study over rejuventation of freshwater great mussels in nine watersystems and considered that the rejuventation within the populations were all along the line poor. This study orients from her work and points to determine if there is a connection between the poor juventation and pollution of nitrogen and phosphorous from industries and private sanitations. The study was performed with the software program ArcGIS9.2 to take out drainage areas for the concerned habitats and contact was made with the concerned authoritys. When it comes to supervision of private sanitations is it the countys and for industries is it the county administrative board.

Om behovet av ett avrinningsområdesanpassat skogsbruk

The Swedish forest have about 100 000 km of watercourses and it?s an important structure in Swedish landscapes and catchments. In some of the watercourses lives spieces like the Freshwater pearl mussel (Margaritifera margaritifera) and brown trout (Salmo trutta) which both are sensitive for inteference from the forestry. The new EU water framework directive has a goal that all surface water will have high or good ecological- and good chemical status at latest by the 22nd December of 2015. The study has been made in the catchment of Håltjärnsbäcken and it is from a national perspective one of the most valuable streams in Sweden and which also have been included in a LIFE-project. The catchment is situated within the Eco-park of Malingsbo-Kloten and managed by Sveaskog AB.

Effekt av parasitinfektion på öringens furagering

Parasiter kan påverka sina värdar på många olika sätt. Flodpärlmusslans (Margaritifera margaritifera L.) glochidielarver lever inkapslade som parasiter på gälarna hos öring (Salmo trutta L.) i flera månader innan de blir frilevande. Genom experiment i ett strömakvarium har denna studie undersökt hypoteserna att öring med inkapslade gälparasiter tar färre byten, och simmar kortare avstånd när de födosöker än öring utan gälparasiter. Resultaten visade att infekterad öring tog signifikant färre byten/minut än oinfekterad öring både i början och i slutet av en födosöksperiod under vilken individerna konfronterades med tvåhundra poteniella byten. Vilket visar att infekterad öring har en lägre furageringshastighet är oinfekterad öring. Däremot påvisades ingen skillnad mellan öring med och utan parasiter med avseende på antal byten tagna i förhållande till avstånd från bytet.  Den lägre furageringshastigheten som påvisades hos de infekterade öringarna tyder på att infektion av flodpärlmusslans larver kan ha negativa effekter på fiskarnas tillväxt, och därmed överlevnad.

Överraskning - Vilka indikatorer påverkar? : En studie av de två fallen Pearl Harbor och Sexdagarskriget

Principen överraskning är en av de äldsta principer som finns att använda i striden. Principen ses som grunden för striden och för vilka metoder som kan använda för att lyckas i striden. Men vad innebär överraskning egentligen och hur har den använts?Uppsatsen kommer att problematisera principen överraskning och anknyta till forskningen om överraskning till Pearl Harbor och sexdagarskriget, som har setts vara typiska överraskningsanfall. Såg anfallen likadana ut och vilka indikatorer utifrån litteraturen påvisar att det var en överraskning?Inledningsvis kommer överraskning beskrivas utifrån vald litteratur för att åskådliggöra innebörden.

Pearl Harbor, 1941 : En teoriprövande fallstudie av Japans flygstridskrafter under anfallet mot Pearl Harbor

Den 7 december 1941 genomförde japanska flygstridskrafter ett massivt bombanfall mot Pearl Harbor. Intentionen med anfallet var att slå ut den amerikanska Stillahavsflottan och därmed erhålla större inflytanade i Stillahavsområdet. Anfallen riktades huvudsakligen mot amerikanska fartyg som låg vid Pearl Harbors hamn men även flygfält i dess närområde drabbades hårt av den japanska offensiven.Syftet med detta arbete är att, med utgångpunkt från John. A Warden III centrala teorier; tyngdpunkter, fienden som ett system och parallell attack, analysera Japans agerande under attacken mot Pearl Harbor för att därigenom urskilja i vilken utsträckning dessa teorier kan tillämpas på de japanska flygstridskrafterna vid anfallet. Undersökningen syftar även till att utröna om de utvalda teorierna är applicerbara på taktisk nivå.

Habitatpreferenser hos tjockskalig målarmussla (Unio crassus) med avseende på vattendjup och beskuggning.

The thick-shelled river mussel (Unio crassus) is a red listed species classified as Endangered (EN) and is also considered within the Habitats Directive. The distribution in Sweden is fragmented and it is mostly occurring in the south eastern parts. We investigated the presence of Unio crassus in a section of the stream Storån, Östergötland County, from Falerum to the inflow into Lake Åkervristen. The environmental parameters investigated were water depth, bottom substrate, shading, water velocity and the slope over the water surface. In this thesis I have focused mainly on water depth and shading, comparing sites with and without mussels.

En utvärdering av två pearl growing-metoder i ISI Web of Science

The purpose of this thesis is to evaluate two pearl growing methods in ISI Web of Science. The methods tested are Find Related Records FRR, an automatic service that uses bibliographic coupling, and Author Keywords AK, where searches are performed using the two first keywords from this field. Both search methods were used on twenty initial documents and the first twenty hits were evaluated for relevance using a binary scale 0,1. The relevance criteria were based on specific information needs connected to every initial document. The measures used to evaluate the effectiveness of the search methods were Precision at DCV=10, P10, and Uninterpolated Average Precision AP.

Utvärdering av rörelsemönster hos öring (Salmo trutta) utifrån otolitmikrokemi

The classic view of trout (Salmo trutta) life history is that trout begins its life in freshwater, migrates to the ocean after about 1-4 years and then returns to freshwater to spawn. As trout fry have been caught at the mouth of the River Emån, near the Baltic Sea, researchers have speculated that some trout emigrate during their first year of life. The purpose of this study was to describe the variation in the length of time trout reside in freshwater before they migrate to the ocean for the first time. Another purpose was to investigate whether it was possible to discern where and how long the fish spent in freshwater and saltwater during different parts of their lives. Between 2007 and 2009, 23 adult trout were captured in the River Emån in southeastern Sweden.

Tritordeum : evaluation of a new food cereal

Tritordeum is the result of a cross between a wild barley (Hordeum chilense) and durum wheat (Triticum turgidum). Tritordeum have high viscosity and a nice yellow colour. The objective of this thesis was to evaluate Tritordeum lines HT 354, HT 361, HT 437, HT 2218 (JB3) and HT 1608 (JB1) for use as a new raw material within the food industry. Analyses made were on dietary fibre, fructan, ash, water content and colour. Compilation of data from analyses made for Agrasys an Agri-Food company in Barcelona having the commercial rights to Tritordeum, included Lutein and rheological properties.

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