Sötvattensmusslor av ordningen unionoida är en av världens mest hotade organismgrupper och tjockskalig målarmussla (Unio crassus) klassas som starkt hotad enligt IUCN:s lista över rödlistade arter. Bevarandearbeten har tidigare utförts där tjockskalig målarmussla har återintroducerats till Klingavälsån och Fyleån i södra Sverige. Vid återintroduktion är utgångspunkten genetiskt släktskap, men när den informationen inte finns väljer man att återintroducera den population som är geografiskt närmast. Syftet med studien var att undersöka ifall geografisk avstånd mellan de fyra vattendragen Bråån, Tommarpsån, Klingavälsån och Fyleån påverkar juvenilöverlevnad. Syftet var även att ta reda på vilken av Bråånmusslor och Tommarpsånmusslor som är bäst lämpad för återintroduktion i Fyleån och Klingavälsån. Jag hade följande hypoteser, (1) Bråånmusslor har högst överlevnad i Bråån, följt av Klingavälsån, Fyleån och Tommarpsån och (2) Tommarpsånmusslor har högst överlevnad i Tommarpsån följt av, Fyleån, Klingavälsån och Bråån. Befruktade musslor fångades in från Bråån och Tommarpsån i maj 2016. Musslorna släppte i från sig glochidielarver som sedan användes till att infektera fiskar. Stensimpor (Cottus gobio) elfiskades från Tommarpsån och elritsor (Phoxinus phoxinus) elfiskades från Bråån, därefter infekterades stensimpor med glochidielarver från Tommarpsån och elritsor med glochidielarver från Bråån. Juvenila musslor släppte från fiskarna 25-35 dagar senare och matades under hela sommaren, därefter sattes musslorna ut i boxar i de fyra vattendragen. Överlevnaden för musslorna mättes och dokumenterades vid två tillfällen. Fyra Kruskal-Wallis tester genomfördes där ”överlevnad” jämfördes med ”vattendrag” för Bråånmusslor och Tommarpsånmusslor. Resultatet stämde inte överens med hypotesen för vare sig Bråånmusslor eller Tommarpsånmusslor, förutom att Bråånmusslor hade lägst överlevnad i det mest avlägsna vattendraget vid andra mättillfället. Överlevnaden för Bråånmusslor skilde sig mellan flera av vattendragen men för Tommarpsånmusslor var det ingen skillnad i överlevnad. Bråånmusslor verkade mer lämpliga för återintroduktion i Fyleån jämfört med Klingavälsån och Tommarpsånmusslor verkade inte sämre lämpade för återintroduktion till vare sig Fyleån eller Klingavälsån. Sammanfattningsvis verkade överlevnaden inte generellt bero på geografisk närhet. Troligtvis har faktorer som lokaladaptation, vattenkvalité och sjukdomar även en påverkan på överlevnaden hos juvenila musslor. / Freshwater mussels are one of the most endangered groups of organisms worldwide, with the thick-shelled river mussel (Unio crassus) being classified as critically endangered according to the IUCN:s red list of threatened species. Conservation efforts have been undertaken in southern Sweden, where the thick-shelled river mussel has been reintroduced to Klingavälsån and Fyleån. Genetic relatedness is typically used as the starting point when reintroducing mussels, but if this information is not available, the population closest geographically is chosen. The objective of this study was to investigate whether the distance between four watercourses, namely Bråån, Tommarpsån, Klingavälsån and Fyleån affects juvenile survival and to determine which population of mussels from Bråån and Tommarpsån is best suited for reintroduction to Fyleån and Klingavälsån. The hypotheses are that (1) Bråån mussels have the highest growth rate in Bråån, followed by Klingavälsån, Fyleån and Tommarpsån, and (2) Tommarpsån mussels have the highest growth rate in Tommarpsån, followed by Fyleån, Klingavälsån and Bråån. Fertilized mussels were collected from Bråån and Tommarpsån in May 2016, and the mussels released glochidia larvae, which were used to infect fish. European bullheads (Cottus gobio) were electrofished from Tommarpsån and European minnows (Phoxinus phoxinus) were electrofished from Bråån, and then the European bullheads were infected with glochidia larvae from Tommarpsån and European minnows were infected with glochidia larvae from Bråån. Juvenile mussels let go of the fish 25 – 35 days later and were fed throughout the summer, after which the mussels were placed in boxes in the four watercourses. Survival of the mussels was measured and documented on two occasions. Four Kruskal-Wallis tests were performed where “survival” was compared with “watercourse” for Bråån mussels and for Tommarpsån mussels. The results did not match the hypothesis for either Bråån mussels or Tommarpsån mussels, except for the fact that Bråån mussels had the lowest survival rate in the most remote stream at the second measurement occasion. The survival of the Bråån mussels differed between several of the streams, but for the Tommarpsån mussels there were no significant difference in survival. The Bråån mussels seemed more suitable for reintroduction into Fyleån compared to Klingavälsån, and Tommarpsån mussels did not seem less suitable for reintroduction to either Fyleån or Klingavälsån. In summary, survival did not appear to generally depend on geographic proximity. Factors such as local adaptation, water quality and diseases likely also have an impact on the survival of juvenile mussels.

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This thesis assesses climate change during the Hypsithermal Climatic Interval through the analysis of freshwater mussel remains from archaeological sites in Eastern North America. Modern climate data was used as a model to test the mosaic consequences of climate change. Freshwater mussels: can be used as indicators of precipitation by examining changes in overall size through time: larger mussels are found in larger streams, while smaller mussels are found in smaller streams. This study combines morphometric and isotopic data from archaeological freshwater mussels at Modoc Rock Shelter, Watson Brake, Plum Creek, Owens site, and Landerneau mounds to assess past climatic conditions. At Modoc Rock Shelter, oxygen isotopic data corroborate morphometric data and show that climate was fluctuating with a period of stability at the onset of the Hypsithermal. The oxygen isotopic data sets from the Louisiana sites show that the mid-Holocene was much warmer than the late-Holocene.

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Genetic variation was examined in two endangered mussel species, Epioblasma brevidens and E. capsaeformis, and a common species Lampsilis fasciola, in the Clinch River, TN, by screening mitochondrial DNA (mtDNA) sequences and nuclear DNA microsatellites. These species use fish hosts with varying dispersal capabilities, ranging from low, moderate, and high, respectively. Patterns of mtDNA polymorphism exhibited different trends for long-term population sizes for each species during the Holocene (~10,000 ya to present); namely, E. brevidens has declined over time, E. capsaeformis has remained stable, and L. fasciola has expanded. Long-term effective population size (Ne) was smallest in E. brevidens, intermediate in E. capsaeformis, and highest in L. fasciola. Moderately diverged mtDNA lineages, perhaps indicative of secondary contact, were observed in E. brevidens and E. capsaeformis. High levels of gene flow (Nm) were estimated among demes of L. fasciola using traditional F-statistics and likelihood estimates of Nm, whereas such metrics were lower in E. brevidens and E. capsaeformis. Data are consistent with population dynamics and life history traits of each species and their fish hosts. Age, shell growth, and population demography of Epioblasma brevidens, E. capsaeformis, and Lampsilis fasciola were studied from 2004-2007 in a 32-km reach of the Clinch River, TN. Observed maximum age and length of E. brevidens was 28 y and 71.5 mm for males and 11 y and 56.6 mm for females; of E. capsaeformis, 12 y and 54.6 mm for males and 9 y and 48.6 mm for females; and of L. fasciola, 45 y and 91.3 mm for males and 13 y and 62.6 mm for females. For all three species, observed maximum age and length was greater among males than females. Estimated population size in this river reach was approximately 43,000 individuals for E. brevidens, 579,000 individuals for E. capsaeformis, and 30,000 individuals for L. fasciola. Mean recruitment y-1 of 1 y-old E. brevidens ranged from 7.1% to 20%, of E. capsaeformis from 4.0% to 32.4%, and of L. fasciola from 5.8% to 25.6%. Population growth rate y-1 was 24.9% for E. brevidens, 34.6% for E. capsaeformis, and -22.4% for L. fasciola. Mortality rates of females were higher than for males of E. capsaeformis and L. fasciola, but not E. brevidens. Juvenile mussels were collected but temporally and spatially variable in occurrence, and a significant component of the age-class structure of all three species. Recruitment was very high during 2006-2007 for E. capsaeformis and other species, likely due to low river discharges in the spring-summer of 2005-2007. Surplus individuals of E. brevidens and E. capsaeformis are currently available to conduct translocations for restoration purposes. Population modeling of Epioblasma brevidens and E. capsaeformis in the Clinch River was conducted to determine suitable harvest levels for translocation of sub-adults and adults, and to determine quantitative criteria for evaluating performance and recovery of extant and reintroduced populations. For both species, the recommended annual harvest was <1% of local population size to minimize risk of decline. Reintroduction modeling indicated that size of the initial population created during a 5 y build-up phase greatly affected final population size at 25 y, being similar to size at the end of the build-up phase, especially when expected growth rate was low, (e.g., 1-2%). Excluding age-0 individuals, age-1 juveniles or recruits on average comprised approximately 11% and 15% of a stable population of each species, respectively. The age-class distribution of a stable or growing population was characterized by multiple cohorts, to include juvenile recruits, sub-adults, and adults. Molecular genetic and demographic data indicated that the ratio of Ne/Nc was ~5% for both species. Based on this ratio and predicted declines of genetic variation at different population sizes, target sizes for reintroduced or recovered populations of each species should be ≥5,000 individuals (Ne=250) and ≥10,000 individuals (Ne=500), respectively, and should be comprised of multiple smaller demes spread throughout a river. Populations of both species are currently large enough to sustain harvest for translocation and reintroduction purposes, offering an effective species recovery strategy. / Ph. D.

Glochidia (larvae) of freshwater mussels are obligate parasites which attach to and become encysted in the gills or fins of host fish species. The immune responses of the host fish to the parasite affects the susceptibility of the fish to glochidia of different mussels. The immune response provides an opportunity to identify which fish species are hosts. The number and variety of mussels in rivers and lakes has sharply declined since the last century due to various anthropogenic factors, and some mussels species are facing extinction. It is an urgent task to preserve these vanishing mussels, or extinction will be inevitable. An attempt was made to develop an assay, using the immunological response to glochidia, to screen fish species for appropriate hosts. This would facilitate the production and rearing of juveniles. In order to design these assays, reagents such as anti-immunoglobulins which can react with antibodies from many different fish species have to be developed. This work was carried out to develop such reagents. Host and non-host fish were immunized with killed bacteria (Brucella abortus) to study their humoral immune response to an antigen. All fish were able to respond well, as measured by agglutination and Western Blot assays. Antibodies produced by the Brucella injections were used to stimulate anti-fish immunoglobulins in goats, and the antisera were tested for their ability to recognize immunoglobulins from different host fish species. The specificities of these reactions were compared to the reactivity of Protein A. Goat antisera were able to cross-react with different fish antibodies, but it was found that Protein A was a more suitable reagent. Protein A is seemingly suitable to identify the host-fish species and could be used as a reagent for the serological diagnosis of various fish diseases. / Master of Science

This thesis focuses on shell shape plasticity of Unio crassus at 12 localities. 1129 shape outlines were used for the purposes of this work. The outlines were gained from 260 individuals in the way of analysing the winter growth lines. The Elliptic Fourier Analysis appeared to be reasonable tool for the bivalves' shells shapes assessment. The winter growth lines' consideration showed great potential for morphometric analyses. The results shows that PC1 and PC2 axes (from principal component analysis of shape coeficients) are growth- dependent. The allometry influence was removed by residual values assessment obtained from generalized linear model (GLM). The age, length and width parameters appears to be favourable combination for general allometry influence removal (by using these parameters as describing variables in GLM model). The results point to significant differences among localities in all assessed parameters. Furthermore, the significant difference in growth speed was approved. Speed growth indicator correlates with shape variables. The localities can be divided into two groups with different growth speed each (Bertalanffy growth constant, length in the third year and age relative length). These groups differs in about 10 mm in average lengths. The most similar localities were "Blanice...

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