This dissertation is composed of three chapters. In chapters 1 and 2, the study mainly focused on the morphological identification of the asteroids in Korea. The first chapter focused on the taxonomy of the genus Henricia, and the second chapter introduced three species of asteroids. The third chapter was focused mainly on the community structure of benthos on settlement plates in major harbors in Korea.
As a result, two new species: Henricia epiphysialis and Henricia sp. nov. (unpublished); six previously recorded species: H. leviuscula, H. nipponica, H. ohshimai, H. pachyderma, H. regularis, and H. reniossa; nine newly recorded Henricia species: H. anomala, H. aspera, H. djakonovi, H. elachys, H. hayashii, H. pacifica, H. perforata, H. oculata, and H. sanguinolenta; and three identified yet unpublished species: H. densispina, H. irregularis, and H. reniossa asiatica, were added to the Korean region. Additionally, two genera, Aleutihenrica and Diplopteraster, and three species of asteroid such as Aleutihenrica beringiana, Diplopteraster multipes, and Solaster paxillatus, were identified. The key to species of genus Henricia in Korea was presented. The detailed morphological characteristics and illustrations of each species were also provided.
The community structure of benthos on settlement plates installed in 14 major harbors in Korea was examined. Environmental factors, such as water temperature and salinity, were measured throughout the study period. Shannon diversity index, PERMANOVA, non-metric multidimensional scaling (NMDS), and SIMPER analysis were used to assess species diversity and the contribution of species differences in the community composition of benthic invertebrates. The PERMANOVA test result shows that there were significant differences between regions across the immersion period. Water temperature and salinity were the main environmental drivers for species composition changes. NMDS shows that the Yellow Sea region has high abundances of dominant taxa such as D. vexillum and M. galloprovincialis. These dominant species were highly influenced by the salinity, as they adjusted very well to the fluctuation of environmental factors. Thus, providing this useful information could generate some countermeasures and proper planning to neutralize the intensity of the influx of dominant yet harmful species in Korea.