This study aims to investigate temporal and spatial distribution in species compo-sition and abundance of siphonophore in relation to hydrographic variables in the wa-ters off southern Taiwan from January 2005 to October 2006. Zooplankton samples were taken from 200 m to the surface at nine sampling stations with Ocean Research Institute plankton net (1.6 m in opening diameter , 330 £gm in mesh size). In total, 72 zooplankton samples were collected and 58 species of siphonophores belonging to 7 families and 20 genera were found, with the mean abundance of 182.2 ¡Ó 38.3 ind./100m3. The six most dominant species were Chelophyes contorta, Bassia bassen-sis, Abylopsis eschscholtzi, A. tetragona, C. appendiculata and Eudoxoides mitra. Together they accounted for over 70.5 % of the total abundance of siphonophore. The species composition of dominant siphonophores were similar among seasons but their abundance were ranked different. The abundance, species number, and species diver-sity of siphonophores were higher in summer than in winter, but showed no signifi-cant difference among stations. Most species of siphonophores were dominated by sexual generation in the study area. The abundance of siphonophores showed signifi-cant positive correlation with temperature. Different predominant siphonophore spe-cies showed different correlationships with hydrographical factors. Only C. contorta and C. appendiulata were positively correlated with temperature, none of the other siphonophores species was significantly correlated with salinity. The abundance of siphonophore in general and most dominant species were positively correlated to zooplankton abundance, suggesting that food sources might be a key factor affecting the distribution patterns of siphonophore assemblages in the study area. Furthermore, the siphonophores found in this study mostly belong to the widespread oceanic spe-cies, and the composition of dominant species were similar to previous studies in the South China Sea.

Temporal and spatial distribution in species composition and abundance of siphonophores in relation to hydrographic variables in the waters off southern and northern Taiwan were investigated from December 2003 to August 2004. In total, 48 siphonophoran species belonging to 18 genera and 7 families were recognized, with the mean abundance of 2226 ¡Ó 1228 ind./1000 m3. The abundance of siphonophores showed an obvious seasonal change, lower in December and February and higher in May and August. The six most dominant species, together they contributed to 66.5 % of the numerical total of siphonophores, were Chelophyes contorta, Bassia bassensis, Chelophyes appendiculata, Abylopsis eschscholtzi, Abylopsis tetragona and Eudoxoides mitra. The dominant siphonophoran species exhibited apparent seasonal succession. Different dominant species showed different seasonal distribution patterns and most species were dominated by sexual generation. Result of the cluster analysis of siphonophoran data revealed 2 station groups. Group¢¹was mostly composed by the stations in February and May, and group ¢º contained the stations in May and August. Forty-two siphonophoran species belonging to seven families and nineteen genera were recognized in the waters off northern Taiwan, with the mean abundance of 7129 ¡Ó 10240 ind./1000 m3. The abundance of siphonophores displaced an apparent seasonal change, significantly higher in February and August and lower in December and May. The six most dominant species, together they contributed to 79.4 % of the numerical total of siphonophores, were Diphyes chamissonis, C. appendiculata, Muggiaea atlantica, Lensia subtiloides, B. bassensis and E. mitra. The dominant siphonophoran species showed obvious seasonal succession and different dominant species exhibited different seasonal distribution patterns. Muggiaea atlantica and L. subtiloides were dominated by polygastric stage, while other species were mostly the eudoxid generation. Result of CA of siphonophores revealed 3 station proups. Group¢¹ was primarily the stations in the northwestern waters off Taiwan waters in December, Group ¢º contained the stations in the northeastern waters off Taiwan in all seasons. Group ¢» was mainly the sations in the northwestern waters off Taiwan in February and May. The mean species number and species diversity were always higher in southern waters than in northern waters of Taiwan, but the overall mean abundance was three times higher in the northern waters than in the southern waters. The overall mean abundance in this study showed higher in December 2003 and lower in February and May 2004. Result of the ANOVA test revealed the significant difference in siphonophoran abundance between May and August 2004 in both southern and northern stations. The abundance of total siphonophores was not significantly correlated with water temperature, salinity and chlorophyll a. The abundance of the six most dominant species in the southern Taiwanese waters was not significantly correlated to water salinity and chlorophyll a, but the abundance of C. contorta, B. bassensis, A. eschscholtzi and C. appendiculata were apparently influenced by water temperature. The abundance of the six most dominant species in the northern Taiwanese waters exhibited different correlationships with hydrographic variables, C. appendiculata showed significantly positive correlation with chlorophyll a, B. bassensis exhibited significantly positive correlation with water temperature, salinity and chlorophyll a, while E. mitra was significantly positively correlated with salinity.

This study is aimed to investigate the species composition and seasonal distribution of siphonophores in relation to water temperature and salinity in the coastal waters, southwestern Taiwan, from June 2001 to October 2002. In total, 39 siphonophoran species belonging to 17 genera and 5 families were identified, with the mean total abundance of 5301¡Ó8525 ind./100m3. The numerical abundance of siphonophores showed apparent seasonal change, higher in spring and autumn and lower in winter. The five most dominant species were Chelophyes contorta, Lensia subtiloides, Sulculeolaria chuni, Bassia bassensis and Diphyes bojani, and contributed to 80.2% of the total abundance of siphonophores. The mean abundance and species number of siphonophores were higher in surface water than in 0~100m oblique tow. The siphonophores found in the present study mostly belonged to the widespread oceanic species or widespread coastal species, and the dominant species were similar to those in the South China Sea. The dominant siphonophoran species exhibited apparently seasonal succession. Different dominant species showed different seasonal distribution patterns and percentage composition of sexual and asexual generations in total population. The total abundance of siphonophore showed significant (p>0.05) correlation with water salinity, but not temperature. The abundance of Chelophyes contorta, Lensia subtiloides, Abylopsis eschscholtzi and Diphyes chamissonis were significantly correlated to water temperature, but the abundance of Sulculeolaria chuni and Abylopsis tetragona showed significantly negative correlations with temperature. The abundance of Chelophyes contorta, Lensia subtiloides and Abylopsis eschscholtzi were significantly negatively correlated to salinity, but Sulculeolaria chuni showed significantly positive correlation with salinity.

The species composition, temporal and spatial distribution of siphonophores in relation to hydrographic variables in the waters off eastern Taiwan were examined during the period from May 2000 to July 2001. In total, 54 siphonophoran species belonging to 21 genera and 6 families were identified, with the mean abundance of 284 ¡Ó 18 inds. /1000m3. The numerical abundance of siphonophores showed an apparent seasonal change, higher in autumn and lower in winter and summer. The six most dominant species were Chelophyes contorta, Abylopsis tetragona, Bassia bassensis, A. eschscholtz, Eudoxoides mitra and Diphyes chamissonisi, and together they contributed to 75.1 % of the numerical total of siphonophores. The mean abundance, but not for species number, of siphonophores was significantly higher in Kuroshio waters than in coastal waters. Most siphonophores found in this study were belonged to the widespread oceanic species, and the dominant species composition was similar to those in the northern South China Sea. The dominant siphonophoran species exhibited apparent seasonal succession. Different dominant species, as well as their ratio of sexual and asexual generations, showed different seasonal distribution patterns. The total abundance of siphonophores was not significantly correlated to water temperature and salinity. The abundance of the six most dominant species showed different correlations with water temperature and salinity. The abundance of C. contorta showed significant positive correlation with water temperature, but negative correlation with water salinity. The abundance of B. bassensis showed significant negative correlation with water temperature, but positive correlation with water salinity. The abundance of E. mitra showed significant negative correlation with water salinity. The others were not significantly correlated to water temperature and salinity.

This study investigated the seasonal and spatial distribution in species composition and numerical abundance of siphonophores in relation to environmental factors in the surrounding waters of Taiwan in February (winter) and May (spring) 2003 and August (summer) 2004. In total, 75 species belonging to 30 genera and 9 families were indentified, with the mean abundance of 387 ¡Ó 97 inds./100m3. The abundance of siphonophores showed clear seasonal change, higher in summer and winter, but lower in spring. The eight most dominant species were Lensia subtiloides, Chelophyes contorta, Muggiaea atlantica, Diphyes chamissonis, Bassia bassensis, C. appediculata, Abylopsis eschscholtzi and D. bojani, which together constituted 78¢H of the total siphonophores. Siphonophores showed higher abundance in the waters of northwestern Taiwan, while the species number and diversity were higher in the waters of eastern and southern Taiwan. Different dominant species showed different distribution patterns, and most species were dominated by sexual generation. The siphonopores assemblages exhibited apparent seasonal variations and were associated with water masses. The siphonophores found in this study mostly belong to the widespread oceanic and coastal species, and the composition of dominant species was similar to the previous studies in the northern South China Sea. The abundance of siphonophores showed significant negative correlation with salinity, while species richness and diversity were positive. Different predominant siphonophore species showed different correlationships with environmental factors; Muggiaea atlantica showed significant negative correlation with temperature, but Bassia bassnsis and Abylopsis eschscholtzi showed significant positive correlation with temperature. Most siphonophores were significantly and negatively correlated with salinity.

This study aims to investigate the spatial and temporal distribution of siphonophores in relation to water temperature, salinity, concentration of chlorophyll a and the abundance of copepods in Tapeng Bay and Kaoping coastal waters from June 1999 to July 2001. In Tapeng Bay, 20 species of siphonophores belonging to 9 genus and 3 families were identified with the mean abundance of 11¡Ó33 ind./100m3. The 5 most dominant siphonophore species in Tapeng Bay were Lensia subtiloides, Chelophyes appendiculata, Lensia subtilis, Bassia bassensis, and Lensia campanella, comprising 85% of the numerical total siphonophores. The siphonophores were mainly found at north station and scarce or even absent at St. N and St. S. Seasonal distribution of siphonophores was inconsistent, but generally had higher abundance in fall and winter. In Kaoping coastal waters, 34 species of siphonophores belonging to 16 genus and 5 families were identified, with the mean abundance of 648¡Ó636 ind./100m3. Seasonal change in numerical abundance of siphonophores was obvious, with higher in spring and autumn. The 5 most dominant species were C. appendiculata, L. subtiloides, Chelophyes contorta, Sulculeolaria chuni and B. bassensis, and comprised 77% of the total counted of siphonophores. The species number, species diversity, and the mean abundance of siphonophores in Kaoping coastal waters were higher than that in Tapeng Bay. The siphonophores found in the present study mostly belong to the widespread oceanic species and widespread coastal species. The distributions of siphonophore were not significantly (p>0.05) correlated to temperature, salinity, concentration of chlorophyll a and the abundance of copepods, except Abylopsis tetragona and Diphyes dispar, that exhibited significant negative correlation with temperature (p<0.01) and chlorophyll a (p<0.01), respectively.

Underwater surveillance missions both for defense and civilian applications are continually demanding the need for unmanned underwater vehicles or UUVs. Unmanned vehicles are needed to meet the logistical requirements for operation over long distances, greater depths, long duration, and harsh conditions. In order to design UUVs that not only satisfy these needs but are also adaptive and efficient, there has been increasing interest in taking inspiration from nature. These biomimetic/bio-inspired UUVs are expected to provide significant improvement over the conventional propeller based vehicles by taking advantage of flexible bodies and smart actuation. In this thesis, jetting jellyfish were utilized as the inspiration to understand the fundamentals of this new form of propulsion and subsequently translate the understanding onto the engineered platform to validate the hypothesis and construct robust models. Jetting jellyfish species are generally smaller in dimensions than rowing jellyfish, consume lower energy for transport, and exhibit higher proficiency. In the second chapter, a bio-inspired stationary jet propulsion mechanism that utilizes an iris diaphragm actuation system was developed. Detailed discussion is provided on the design methodology and factors playing the leading role in controlling the vortex formation. The propulsion mechanism was intended to mimic the morphological and deformation features of Sarsia sp. jellyfish that measures approximately 1 cm in diameter. The performance of experimental model was analyzed and modeled to elucidate the role of structure and fluid displacement. Utilizing the results from Chapter 2, a free-swimming jellyfish-inspired robot (named JetPRo) was developed (also utilizing an iris diaphragm) in Chapter 3 and characterized for relevant propulsive metrics. A combination of theoretical modeling and experimental analysis was used to optimize the JetPRo's gait for maximum steady-state swimming velocity. Next, an attempt was made towards creating a free-swimming jetting robot (named JP2) using a guided cable mechanism to achieve the desired actuation and improve the propulsion while simplifying the drive mechanism. Using JP2 robotic model, a systematic set of experiments were conducted and the results were used to refine the theory. Based upon the comprehensive computational analysis, an optimized swimming gait was predicted and then validated. A modular robot inspired by siphonophores was developed and initial efforts were made in laying down the foundation for understanding of this complex locomotion mechanism. Siphonophores are colonial organisms consisting of several jetting bodies attached to a central stem. An experimental model was developed mimicking the multimodal swimming propulsion utilized by Siphonophores. Several swimming gaits inspired by the natural animal were replicated and the preliminary performance of the experimental model was quantified. Using these results, an analysis is presented towards further improving the design and assembly of a siphonophore-inspired robot. / Master of Science