碩士 / 國立澎湖科技大學 / 水產養殖系水產資源與養殖碩士班 / 105 / Coastal wetlands are diverse environments with high basic productivity, and they serve as important habitats and feeding and reproductive sites for many aquatic fish species. These regions, however, are easily affected by factors such as temperature, salinity, topography, and sediment, which limit the occurrence and activities of various fish species. The Caiyuan Wetland in Penghu bay, is the only wetland in this region. This study compared the environmental differences among fish habitats within this wetland; three sampling sites, i.e., mangrove forest, abandoned fish farm, and tide pool were investigated using seine-net to sample each sampling sites across two years to determine the occurrence of fish species in different habitats and seasons.
This study was conducted for 27 months, between April 2013 and June 2015. Each of the three sampling sites was sampled once a month, resulting in 81 samples in total, which comprised 10 orders, 30 families, 58 genera, and 90 species of fishes. Among these, 42 species were detected in a single sampling sites, and 26 species were detected in all three sampling sites. β-diversity and individual fish species diversity index were lower in tide pools than in the other two sampling sites, suggesting that ecological conditions of tide pools make this a relatively unfavorable habitat for a large number of species. Moreover, data from the two years between June 2013 to May 2015 were analyzed; a total of 10 orders, 29 families, 55 genera, and 80 species of fishes were observed. In the two-year period, there were significant differences in the richness in the mangrove forests during winter of the first year, and in the tidal pool during fall and other seasons of the second year. There were significant differences in the abundance in the abandoned fish farm during winter of the first year and in the spring and other seasons of the second year. When data from both years were comparatively evaluated on a monthly basis, the occurrence of the same fish species was consistently lower than 50%, except in January, indicating that more species composition will change in the same season. When categorizing data by the season, the similarity of fish species appearing from fall to winter was lower, and the species richness and diversity index were lowest in winter and spring. When fish species were sorted in the decreasing order of number of individuals, short-term and long-term migratory species appeared. Furthermore, comparison of total length revealed the fishes were in various stages of development, ranging from larval to juvenile stages, as well as the individuals had developed within the sampling habitat or not; these observations suggested the Caiyuan Wetlands serves as a spawning and breeding ground for these species of fish. The non-metric multidimensional scaling (nMDS) and analysis of similarities (ANOSIM) assessment of whether the structure of fish species temporal and spatial variation revealed that fish species in the three sampling areas did not show significant differences in structure (Global R = 0.169, p < 0.001), but the richness in the abandoned fish farm was greater and differed from those in the other two sampling areas. This suggests that the narrow inlets through which water flows in and out and the large surface area of the water body are the main environmental factors that did not change much in the abandoned fish farm than in the other two sampling areas, in addition to being less affected by tides. Analysis of the relationships between the structure of fish species among the seasons of the two years also showed that there were no significant differences (Global R = 0.336, p < 0.001). However, pairwise analysis of sampling areas during the same season showed that the relationship between the structure of fish species differed between abandoned fish farm and other sampling areas in summer, and tide pool in winter. This shows that the abandoned fish farm supports the life of many fish species during summer and winter.
The above results reveal that in the Caiyuan coastal wetland, although the structure of fish species show no significant difference regardless of the sampling area or season, pairwise analysis between sampling areas or seasons reveal that changes in habitat characteristics or time is an important factor affecting the structure of fish species and is a cause of changes in fish species composition. Thus, protecting the integrity of coastal wetland environments, continued monitoring, and long-term use of data to explain spatial and temporal changes comprise the most important foundation for understanding wetland ecosystems, and also serve as important reference data for planning any change or performing any developmental activities.
| Identifer | oai:union.ndltd.org:TW/105NPHT0833002 |
| Date | January 2017 |
| Creators | TSAI, YU-SHAN, 蔡昱珊 |
| Contributors | TSENG, CHIEN-CHANG, 曾建璋 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 110 |
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