Blötdjur (Mollusca) tillhör en av de mest hotade taxonomiska grupperna i världen och musselpopulationer (Bivalvia) har drastiskt setts minska. Den avtagande tillväxten hos musselpoulationen kan bero på faktorer så som minskning av värdfisken, försurning, invasiva arter, föroreningar och igenslamning av bottnar. Alla arter av stormusslor (Unionoida) är känsliga för eutrofiering och fysiska förändringar av deras livsmiljö och kan därmed användas som indikatorer för höga naturvärden eller som indikator på vattnets kemiska kvalitet. För att en musselpopulation skall vara livskraftig krävs en föryngring på mellan 10 till 20 procent. Med föryngring menas andelen juvenila i populationen. I Västra Götalands län visar endast hälften av 33 tidigare  undersökta populationer upp en tillräcklig föryngring. Men när är egentligen musslan juvenil och när övergår den till adult? Idag finns få studier gjorda på stormusslor gällande ålder vid könsmognad. Oftast används uppskattade värden eller andra arters ålder vid könsmognad. Detta arbete syftar till att undersöka tillväxttakten för den allmänna dammusslan. Tillväxten mättes som differenserna av avståndet mellan årsringarna på musselindividernas skal. Med hjälp av den årliga tillväxten kunde en exponentiell tillväxthastighet räknas fram vilken indikerade när tillväxten hos de flesta individer avtog. Brytpunkten som indikerar att tillväxten avtar räknades fram med hjälp av Von Bertalanffys tillväxtmodell som visar tillväxt över tid. Genom att veta i vilken ålder tillväxten avtar kan en slutsats om eventuell könsmognad dras då individen börjar fördela mängden tillgänglig energi till fler funktioner än tillväxt, där reproduktion är den troligaste. Det är viktigt att veta i vilken ålder en art blir könsmogen i bevarandesyfte då en mussla anses vara mycket känslig i sina juvenila år. Resultaten i denna studie visar att tillväxten avtar vid en ålder av 4 år för en av de undersökta sjöarna. I de övriga 2 avtog tillväxten innan musslan uppnåt en ålder av 3 år. Att åldern då tillväxten avtar skiljer sig mellan sjöarna kan bero på att livsförutsättningarna i sjöarna är olika gynnsamma. / Molluscs (Mollusca) belong to one of the most threatened taxonomic groups in the world and mussels (Bivalvia) have been observed to drastically decrease. The reduced growth of the mussel population may depend on factors such as decrease of the host fishes, acidification, invasive species, pollution and siltation of the seabed. All species of large mussels (Unionoida) are sensitive to eutrophication and physical changes in their habitat and can thus be used as indicators of territories with high conservation value or as an indicator of the chemical quality of the water. For a mussel population to be viable it requires a mean the proportion of juveniles (rejuvenation) in the population between 10 to 20 percentages. In Västra Götaland country only half of the previously 33 studied populations show satisfactory rejuvenation. When a mussel is considered to be a juvenile or adult is contentious. Today there are few studies on age at maturity of unionid mussels. Most often estimated values or knowledge of other species age at maturity is used. This work aims to investigate the growth of Anodonta anatina. Growth was measured as the differences in the distance between growth rings on each of the mussel individuals shell. With the annual growth rings an exponential growth rate was calculated that indicated the year in which most of the individuals slowed their growth. The breaking point was found using Von Bertalanffys growth model which indicates growths over time. Knowing the age at which most mussels slows their growth can give us a conclusion of possible age when sexual maturity occurs. The conclusion can be made upon the knowing that an individual starts to allocate the amount of energy available to more features than growth, where reproduction is the most likely. It is important to know the age at which spices reaches sexual maturity due to conservation purposes. A clam is considered very sensitive in its juvenile years. The result in this study shows that growth is slowing at the age of 4 years for one of the studied lakes. In the other two studied, the growth slowed before the mussel attained the age of 3 years. The age at which growth slows differ between lakes and may due to that natural conditions in lakes are various favorable.

Le Cuivre (Cu) appartient aux métaux majeurs contaminant les écosystèmes dulcicoles européens. Les bivalves sont des filtreurs qui bioaccumulent fortement les métaux lourds comme le Cu, lequel, en excès cause de graves troubles métaboliques, et physiologiques. Le but de cette thèse est d'étudier les mécanismes de toxicité et de détoxication du cuivre chez Anodonta cygnea et Anodonta anatina, bivalves largement répandus dans les eaux continentales. L'effet du Cu a d'abord été étudié sur le transport cellulaire du calcium (Ca). Le Ca intervient dans de nombreux processus biologiques et le métabolisme calcique est connu pour être perturbé par le Cu chez les mollusques. L'inhibition par le Cu de l'activité de la Ca2+-ATPase de la membrane plasmique (PMCA) a été observée après 4 jours d'exposition. La récupération totale de l'activité enzymatique a été notée dans les reins et les branchies, après 7 jours d'exposition à concentration environnementale, mais pas à plus forte concentration. L'inhibition des PMCA pourrait entraîner des perturbations de l'osmorégulation et de la réabsorption rénale du calcium chez les moules et conduire à une carence. La récupération de l'activité enzymatique suggère l'induction de mécanismes de détoxications. Les composés riches en thiol, impliqués dans l'homéostasie et la détoxication des métaux ont donc été étudiés dans une seconde étape. Nos résultats montrent la présence d'un peptide riche en cystéine, différent du glutathion, et détecté dans la glande digestive et les branchies des bivalves exposés ou non au Cu. Ce peptide, augmente significativement dans les branchies, après exposition au Cu suggérant son implication dans sa détoxication / Copper (Cu) belongs to the major metals causing environmental contamination in European fresh water ecosystems. Filter feeding bivalves have a high bioaccumulation potential for heavy metals as Cu, which at high concentration can cause serious metabolic, physiological impairments. The objectives of this thesis are to acquire knowledge about toxic effects and detoxification mechanisms of Cu in Anodonta cygnea and Anodonta anatina, two mussels species widely distributed in continental waters. Because calcium (Ca) plays a fundamental role in numerous biological processes, Cu effect was studied first on cellular calcium transport which is known to be disturbed by Cu in molluscs. In a second step, investigations have been carried out on Cu detoxification mechanisms by thiol compounds known to be involved in homeostasis of essential trace metals and in metals cell detoxification. Cu inhibited plasma membrane Ca2+-ATPase (PMCA) activities upon 4 days of exposure was obtained. Total recovery was observed at day 7 in kidneys and gills under exposure to environmental Cu concentration but not at higher level of exposure. PMCA inhibition may entail disturbance of osmo-regulations and calcium renal re-uptake in mussels and lead to continuous under-supply of Ca. Recovery of the enzyme function suggests that metal-detoxification is induced. Our results showed the presence of a cysteine-rich peptide different from glutathione, detected in the digestive gland and the gills from controls and Cu exposed bivalves. This peptide, observed in absence of metal exposure in both organs, increased significantly in gills after Cu exposure suggesting its implication in Cu detoxification mechanisms

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. Most of the countys had a very difficult way to reach their data of the private sanitations and those who had data had great holes in their knowledge in them. The greatest emission of nitrogen was without doubt the industries, but a more even allocation could be seen in the pollution of phosphourus, where the industries and the private sanitations stood for about fifty- fifty of the pollution. The greatest emission of nitrogen and phosphourus happened in Viskan, in the drainage area for Lekvad,there it was a lack of mussels. The species of Anodonta anatina showed a strong positive correlation between emission of nitrogen and phosphourus with the way of juvenile mussels in the population. More studies is need to do in these areas, both when it comes to continuing mapping of rejuventation within the freshwater great mussels in several waters and template value for pollution of nitrogen and phosphourus, that is very doubtful today. Even studies concerning other factors, like predation, host fishes and the influence of poison and medic drugs is needing to do, as it is few studies concerning this today.

<p>Common species of freshwater mussels may, like the freshwater pearl mussel (<em>Margaritifera margaritifera</em>) 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. Most of the countys had a very difficult way to reach their data of the private sanitations and those who had data had great holes in their knowledge in them. The greatest emission of nitrogen was without doubt the industries, but a more even allocation could be seen in the pollution of phosphourus, where the industries and the private sanitations stood for about fifty- fifty of the pollution. The greatest emission of nitrogen and phosphourus happened in Viskan, in the drainage area for Lekvad,there it was a lack of mussels. The species of <em>Anodonta anatina </em>showed a strong positive correlation between emission of nitrogen and phosphourus with the way of juvenile mussels in the population. More studies is need to do in these areas, both when it comes to continuing mapping of rejuventation within the freshwater great mussels in several waters and template value for pollution of nitrogen and phosphourus, that is very doubtful today. Even studies concerning other factors, like predation, host fishes and the influence of poison and medic drugs is needing to do, as it is few studies concerning this today.</p>

Den globala uppvärmningen förväntas öka jordens medeltemperatur framledes, vilket innebär att nederbördmönster kommer att ändras till följd av torka och översvämningar. Detta kommer att innebära ett ökat hot för många sötvattensmusslor, som redan är en av de mest hotade grupperna i världen. Temperaturen är en essentiell abiotisk faktor som styr fortplantning, tillväxt och överlevnad. Att mäta kritiskt temperaturmaximum (KTM) är en metod som är framtaget för att användas för att få en förståelse huruvida organismer tål värmeökningar. Under processen sker en gradvis uppvärmning under ett snabbt förlopp, och vid uppnådd KTM utsätts organismen för en extrem stress. Vid flertalet utförda inventeringar i Sverige har uteblivna föryngringar av sötvattensmusslor upptäckts. Syftet är därav att vi i detta experiment ska se om det råder skillnader i värmekänslighet hos befruktade musslor kontra obefruktade musslor. Hypoteserna är (1) befruktad dammussla når KTM tidigare än obefruktad dammussla och (2) befruktad dammusslas fot är utan rörelsekontroll vid en lägre temperatur än hos de obefruktade.  Allmän dammussla (Anodonta anatina) användes till experimentet, då den är helt utesluten ur den internationella rödlistan och vanligt förekommande i svenska sötvatten. Musslorna, vilka plockades i Alsterälven, acklimatiserades i fyra dygn i 10 °C. Under experimentet värmdes vattnet kontinuerligt med 0,3 °C/min, tills KTM hade uppnåtts. Resultatet för hypotes (1) visar att befruktade dammusslor hade ett signifikant högre KTM än obefruktade (t-test, p=0,039), vilket är tvärtemot min hypotes. Resultat för hypotes (2) visar ingen skillnad mellan grupperna (t-test, p=0,54). Varför befruktade musslor uppnådde ett högre KTM skulle kunna bero på att glochidierna stört filtreringen, så pass att gälfunktionen stärkts, vilket lett till att de klarar att hålla igång filtreringen och sin egen metabolism vid högre temperaturer. Mer studier behövs för att få en ökad förståelse över musslors känslighet av temperaturförändringar. / Global warming is expected to increase the earth's average temperature in the future, which means that precipitation patterns will change as a result of droughts and floods. This will pose an increased threat to many freshwater mussels, which are already one of the most endangered groups in the world. Temperature is an essential abiotic factor that controls reproduction, growth and survival. Critical temperature maximum (CTM) is a method that has been developed to be used to gain an understanding of whether organisms can tolerate heat increases. During the process, a gradual heating takes place during a rapid process, and when CTM is reached, the organism is exposed to extreme stress. In the majority of inventories carried out in Sweden, missing rejuvenations of freshwater mussels have been discovered. The purpose is that in this experiment we will see if there are differences in heat sensitivity of fertilized mussels versus unfertilized mussels. The hypotheses are that (1) fertilized mussels reaches their CTM earlier than unfertilized mussels and (2) fertilized mussels relax their foot completely at a lower temperature than the unfertilized mussels. The result for hypothesis (1) shows that fertilized mussels had a significantly higher CTM than unfertilized (t-test, p = 0.039), which is contrary to my hypothesis. Results for hypothesis (2) show no difference between the groups (t-test, p = 0.54). The common duck mussel (Anodonta anatina) was used for the experiment, as it is not in the international red list and is commonly found in Swedish freshwaters. The mussels, which are from the Alsterälven River, were acclimatized for four days in 10 °C river water before the experiment. During the experiment, the water was continuously heated at 0.3 °C/min, until the CTM was reached. Why fertilized mussels achieved a higher CTM could be due to the fact that the glochidians disrupted the filtration, so much so that the gill function was strengthened, which led to them being able to keep the filtration going and their own metabolism at higher temperatures. More studies are needed to gain an increased understanding of mussels' sensitivity to temperature changes.

Sötvattensmusslor är viktiga i ekosystem där de finns, för människan utgör de även en ekosystemtjänst då de filtrerar vatten. De stora sötvattensmusslorna kallas stormusslor och finns i både sjöar och vattendrag i Sverige. I Vänern har fyra av de inhemska arterna noterats. Fetchen är längden på den öppna vattenytan från en punkt på land till närmsta land eller ö. Beroende på en strands storlek på fetch kan bottensedimentet se annorlunda ut. Musslorna är bottenlevande och spenderar mycket tid nedgrävda i bottensedimenten. När musslorna är uppe och filtrerar på bottenytan sitter de halvt nergrävda med bakänden uppåt. I denna rapport presenteras stormusslornas förekomst och dess relation till stränders fetch. Mer kunskap om stormusslorna behövs för att kunna utveckla ett mer anpassat naturvårdsarbete för dem. Inventering av musslor har skett på 20 olika platser i sydöstra Vänernområdet. Denna studie visar att en trend till ett samband finns mellan förekomst av stormusslor och lokalens fetch. Fetchen påverkar den maximala tätheten som musslorna kan uppnå. Analys ger statistisk signifikans på att tätheten minskar med ökad fetch. Tidigare forskning visar på liknande resultat. Emellertid tycks fler variabler vara beroende faktorer för hur mycket och om fetchen påverkar musslorna. / Freshwater bivalves are important organisms in the ecosystems they live, they also function as an ecosystem service for the human society. Swedish freshwater bivalves are divided into two groups; one with freshwater clams Sphaeriidae, and freshwater mussel with polyphile bivalves that are larger. Freshwater mussel lives in lakes and rivers, in Lake Vänern four species of the Swedish freshwater mussel have been observed. Fetch is the length of the open water from a point on shore to the nearest land or island. The structure of the lake bottom sediment can vary dependent on what value of fetch a shore has. In this report the freshwater mussel’s relation to the shore fetch is presented. More knowledge of the freshwater mussel is needed to develop a more suitable conservation work for them.    Inventory of mussel have been done on 20 different places in the southeast area of Lake Vänern. The results in this study shows a trend towards a relation between presence of freshwater mussel and shore fetch. Analysis on the highest density of mussel when the fetch data is divided in different classes shows a statistic significance for reduced density of mussel with increased fetch. Previous research shows similar results. However, more variables seem to be dependent factors for how and if fetch affect mussel.