Thesis (Ph. D.)--Oregon State University, 1988. / Typescript (photocopy). Includes bibliographical references (leaves 101-114). Also available on the World Wide Web.

P. magnifica is an invasive freshwater bryozoan species which is native to the North America. The aim of this thesis is to ascertain the pace of the colonies' growth. The survey was carried out in three locations during twenty-one days in July 2018.

Anemonefish are one of the main groups that have been used over the last decade to empirically measure larval dispersal and connectivity in coral reef populations. A few species of anemones are integral to the life history of these fish, as well as other obligate symbionts, yet the biology and population structure of these anemones remains poorly understood. The aim of this study was to measure the genetic structure of these anemones within and between two reefs in order to assess their reproductive mode and dispersal potential. To do this, we sampled almost exhaustively two anemones species (Stichodactyla gigantea and Heteractis magnifica) at two small islands in Kimbe Bay (Papua New Guinea) separated by approximately 25 km. Both the host anemones and the anemonefish are heavily targeted for the aquarium trade, in addition to the populations being affected by bleaching pressures (Hill and Scott 2012; Hobbs et al. 2013; Saenz- Agudelo et al. 2011; Thomas et al. 2014), therefore understanding their biology is crucial for better management strategies. Panels of microsatellite markers were developed for each species using next generation sequencing tools. Clonality analyses confirm six pairs of identical genotypes for S. gigantea (n=350) and zero for H. magnifica (n=128), indicating presence/absence of asexual reproduction in this region. S. gigantea showed low structure between islands (FST= 0.003, p-value= 0.000), however, even if the majority of the individuals were unrelated (r~0), 81 families that shared 50% of their genetic material formed from two to four members were found. Out of these families, 45% were found with individuals only within Tuare Island, 11% only in Kimbe Island, and 44% were sharing individuals among islands. In comparison, H. magnifica showed no structure (FST= 0.002, p-value= 0.278), mean relatedness indicated the majority of individuals were unrelated, and 31 families were identified. Families again consisted from two to four members and were found within Kimbe Island 90% of the time, and shared between islands the remaining 10%. Results show the first genetic evidence of their reproductive characteristics, high levels of connectivity among islands and significant levels of genetic relatedness among individuals within islands.

Broad-scale population genetics can reveal population structure across an organism’s entire range, which can enable us to determine the most efficient population-wide management strategy depending on levels of connectivity. Genetic variation and differences in genetic diversity on small-scales have been reported in anemones, but nothing is known about their broad-scale population structure, including that of “host” anemone species, which are increasingly being targeted in the aquarium trade. In this study, microsatellite markers were used as a tool to determine the population structure of a sessile, host anemone species, Heteractis magnifica, across the Indo-Pacific region. In addition, two rDNA markers were used to identify Symbiodinium from the samples, and phylogenetic analyses were used to measure diversity and geographic distribution of Symbiodinium across the region. Significant population structure was identified in H. magnifica across the Indo-Pacific, with at least three genetic breaks, possibly the result of factors such as geographic distance, geographic isolation and environmental variation. Symbiodinium associations were also affected by environmental variation and supported the geographic isolation of some regions. These results suggests that management of H. magnifica must be implemented on a local scale, due to the lack of connectivity between clusters. This study also provides further evidence for the combined effects of geographic distance and environmental distance in explaining genetic variance.

Pectinatella magnifica is a fresh water invertebrate colonial animal originating from North America which spreading, throughout Europe as well as Asia, has recently reached a characteristics of invasion. Charakter of the colonies, their seasonnal dynamics and other development aspects have been studied at six destinations in South Bohemia (lake Cep, Nový Lipnický pond, Hejtman pond, Nový Kanclíř pond, Vlkov sandpit and Hnevkovice water reservoir). Repeated biomass quantitative collections have been carried out in 10 m transects alongside the shoreline. Also the environmental factors have been found out (temperature, conductivity, water reactions, transparency, trophia, colonies substrate) and charakteristics of individual invaded reservoirs. The list of currently known destinations has been completed with another reservoirs into which the species has spread out.

Pectinatella magnifica is a colony of freshwater organisms, which are most often found on the submerged parts/branches of coastal plants, but also fixed to stones, growing at the bottom of ponds, or free - floating. These organisms can be found mostly in oligotrophic to mesotrophic waters, and appear to thrive in temperatures that reach 20°C during colonisation. They were first found and described in Philadelphia in 1851, by Joseph Leidy. Although Pectinatella magnifica originates from North America, it has now become an invasive species on the other continents. The first recorded occurrence in Europe was during the 1980s in Hamburg, where it was probably transported on ships' hulls. In the Czech Republic it was recorded for the first time in rivers Vltava and Labe in the first half of the 20 th century. The most common method of its propagation is through internal buds, called statoblasts, fitted with hooks that make it able to cling to any surface, and allow easy distribution over long distances and otherwise impossible terrain. This study uses AFLP analysis of statoblast DNA to analyse the genetic diversity within P. magnifica colonies themselves, changes over time, and between different sites within the Protected Landscape Area (PLA) and a Biosphere Reserve (BR) of Třeboňsko, namely ponds Veseli I, Staňkovský, Nový Kanclíř, Cep, Vlkov and Nový Lipnický.