碩士 / 國立臺灣海洋大學 / 海洋生物研究所 / 97 / Copepods provide the food for the larvae of several economically important fish species. This way copepod abundance affects the recruitment of fish and fishery resources. It is important for this reason to understand and unveil copepod swarming behavior. We currently explore this swarming behavior of copepods at the coral reef area of Lungdong Bay. We are particularly interested in the possible mechanism of copepod swarming. We are taking samples by SCUBA diving, and we deploy plankton net, suction device, and underwater photographic apparatus. We record the topography of underwater landscapes in order to correlate this with swarm-formation. These field observations show that the copepod Dioithona sp. nov. form swarms above white sand that is surrounded by reef with an algal bed on top of the reef. Swarms are composed of adult copepods (the majority are females) and advanced juvenile stages（CV）. Therefore there is reproduction reason to form swarm phenomenon in this research area. Moreover there is undiscovered that fishes attacked swarming copepods in 655pcs swarming research observation. It is thus evident that swarm formation can against attack by predators. Apparently, copepod abundance is related to the change of sea water temperature. Copepod densities reached highest values in July when the temperature is rising. The position of swarms and the average density is likely to be negatively affected by typhoons. Copepods were observed to form the largest swarms at locations with calm waters. Lab experiments showed that Dioithona sp. nov. provided swarming when triggered to do so by artificial light. Dioithona sp. nov. shows positive phototaxis. In a positive phototaxis experiment with Dioithona sp. nov. using different light colors (blue, green, yellow, and red）it was found that Dioithona sp. nov. formed highest density swarms at blue light color. The lowest density was formed at red light color which could be absorbed at 4-5 water depth. This way we explain that Dioithona sp. nov. shows a low positive phototaxis intensity to red light color. However, where the copepod Dioithona sp. nov. shows swarm forming behavior in nature, blue, green and yellow wave bands of the electromagnetic spectrum are available. One of the objectives of the present proposal is, therefore, to disentangle the respective importance of different colors as cues for swarm formation.
| Identifer | oai:union.ndltd.org:TW/097NTOU5270009 |
| Date | January 2009 |
| Creators | Yu-Hsin Hsiao, 蕭育欣 |
| Contributors | Jiang-Shiou Hwang, 黃將修 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 114 |
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