碩士 / 國立清華大學 / 生命科學系 / 88 / To understand the biodiversity and the periodic fluctuation of the fish in Shuangchi river estrarine of northeastern Taiwan, related with the season and the climate, we collected juvenile, young, immature, and adult fish individuals every night, with the tool of small trawl of fishing elvers on the west side of Fu-Long harbor from Dec 27, 1998 to May 31, 2000. Totally, we fished 243,341 individuals of 20 orders, 76 families, 236 species, including post larvae, juvenile, young, immature, adult ones, and also obtained the periodic fluctuation and the body size of every kinds of fish for ecological study on estuarine fishes. The superior species whose amount is more than 1,000 are Mugilidae(Liza macrolepis, and Valamugil formosae, mainly), Engraulis japonicus, Anguilla japonica, Anguilla mamorata, Leiognathidae, Sardinella melanura, Sicyopterus micrurus, Terapon jarbua, Ambassis miops, Atherion elymus, Leiognathus lineolatus, Spratelloides gracilis, Bathygobius fuscus, successively. These superior species groups constituted approximately 97.2% of the total collection, and most of them are coastal epipelagic migratory or amphidromous fishes.
Analyzing the lunar data, we found that the number of species and the total amount of fish collected had an inverse proportional relationship. From May,1999 and Sep,1999 of lunar time, the number of species and the air temperature had an obviously positive proportional relationship, but the precipitation didn’t. During the temperature-rising phase in Shuangchi river estuary on March and April of lunar time, the total amount of the fish is more abundant. When the precipitation was more than average value, the total amount of the fish would decrease temporarily. The guild types of the superior fishes belong to coastal epipelagic migratory, amphidromous, and estuarine, mainly. Although the total amount of the fish whose habitat is around the rocky or sandy shore is less here, the number of species of these fish is more. Because the coast of the Northeastern Taiwan was mostly rocky, the large overslaugh in Shuangchi river estuary is unusual. The fish from Shuangchi river, Long-long brook, and Yenliao Bay coexisted here and there were large amount of fish larvae of various guild types living here. Therefore, it is important to protect the highly biodiversity and also economic fish larvae here.
Comparing the number of Anguilla japonica elvers annually with the El Niño phenomena(El Niño-Southern Oscillation, ENSO), we found that the last two high peaks of A. japonica elvers amount approximately matched to the last two ENSO years(1990~92/1991~1994;1998~99/1997~98). However, the other two peaks of elvers in 1970~71 and 1979, happened between one intensive and one weak ENSO years. It is possible that the annual amount of A. japonica elvers might be related to the periodical changes of ENSO years. Additionally, when comparing the occurrence time and the amount of A. mamorata elvers of Shuangchi river estuary of Northeastern Taiwan with those of Hsuikukuan river estuary, we found that the largest amount of A. mamorata elvers occurred in winter and summer, respectively. And the proportion of A. mamorata and A. japonica elvers in these two places was also different. It is valuable to study the different phenomenon between these two kinds of Anguilla elvers of these two places in Taiwan. Furthermore, the decreasing number of amphidromous fish larvae, such as S. micrurus, may be related to the destruction of natural Shuangchi river and Long-long brook.
By this method, we can obtain the juvenile, young, immature, and adult individuals, dissimilarly to the fish individuals fishing by general ichthyoplankton nets. It is possible to use this easy method to study the young fish individuals around Taiwan coast in long term.
| Identifer | oai:union.ndltd.org:TW/088NTHU0105054 |
| Date | January 2000 |
| Creators | Chia-Fu Wu, 吳家福 |
| Contributors | Chyng-Shyan Tzeng, 曾晴賢 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 169 |
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