博士 / 國立臺灣大學 / 動物學研究所 / 91 / In order to reveal the feeding habits, food resource partitioning and guild structure of odontocetes in Taiwanese waters, the stomach contents were used to identify and enumerate the prey they consumed. Using data collected during 1994 to 2001, which included a total 150 stomach samples collected from 14 odontocetes species. The Risso’s dolphin predominantly fed on enoploteuthid squid, with 90.5% of total number of prey. The diet of Fraser’s dolphin was dominated by hatchetfish, with total prey count of 50.6%. The pantropical spotted dolphin primarily consumed lanternfishes which comprised 49.8% of total number of prey. The diet composition of these three dolphins all showed seasonal variation. The food niche width (B=1.6) of Risso’s dolphin was much narrow than that of Fraser’s dolphin (B=4.4) and pantropical spotted dolphin (B=5.1). The low global overlaps found among the food niches of those three sympatric dolphins, indicating that they have succeeded in partitioning the food supply. Difference in feeding depth and food preferences could reduce the direct food competition. Enoploteuthis chunii, Sthenoteuthis oualaniensis and Taonius pavo was the primary prey in the diet of pygmy sperm whale, while E. chunii, Histioteuthis miranda and T. pavo were the most important preys ingested by dwarf sperm whale. Although the primary preys they ingested were very similar, the ratio of each primary prey comprised differently. Pygmy sperm whale fed on much larger T. pavo than those were ingested by dwarf sperm whale, while dwarf sperm whale ingested more H. miranda than pygmy sperm whale did. This result supports the view that the pygmy sperm whale lives seaward of the continental shelf and the dwarf sperm whale lives in the more coastal waters.
Five major feeding guilds were identified by cluster analysis, which included a total 150 stomach samples collected from 14 odontocetes species. The first to forth group were predominantly fish eaters, while the fifth group comprised all teuthivorous odontocetes. The odontocetes off west coastal Taiwan fed primarily on croakers (Sciaenidae), needlefishes (Belonidae), jacks (Carangidae), octopus (Octopidae) and loliginid squid (Loliginidae). Off eastern Taiwan waters, the lanternfishes (Myctophidae), enoploteuthid squid (Enoploteuthidae) and flying squid (Ommastrephidae) were primarily consumed by odontocetes. The dendrogram of guild structure was very close to dendrogram of phylogenetic relationships among delphinid cetaceans. The third group belonged to the subfamilies Delphininae, the forth group belonged to Stenoninae and the second guild in fifth major group belonged to Globicephalinae in this study. The odontocetes in the same guilds could reduce the competition by partitioned the habitat spatially and temporally.
| Identifer | oai:union.ndltd.org:TW/091NTU00312001 |
| Date | January 2003 |
| Creators | Ming-Chih Wang, 王明智 |
| Contributors | Lien-Siang Chou, Kwang-Tsao Shao, 周蓮香, 卲廣昭 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 136 |
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