碩士 / 國立海洋大學 / 海洋生物研究所 / 90 / Bottom trawl fishery is receiving more and more attentions these years because of its highly by-catch rate and serious damage to the seabed. Fishery management will need to protect the habitats and the environment to maintain biodiversity and resources sustainable. In Taiwan, studies in the past were usually focused on single specie or stock, very few papers studied fisheries from community and ecosystem approach. We don’t have many data on the species composition and the by-catch information. Therefore, the purpose of the present study is to study the community structure of bottom trawl fishes from the two traditional trawl fishery grounds in Aoti and Tahsi, north-eastern Taiwan and one non-traditional fishing ground, Cinshan in northern Taiwan. The study period was from February 2000 to April 2001, which covers four major fishing period: early spring, summer, fall and the next early spring. Three trawl areas, Cinshan, Aoti and Tahsi and various water depth were chosen ranged from 50m to 800m according to the different topographic characters in these areas. By doing this, we are able to understand the temporal and spatial distribution including both horizontal and vertical distribution of demersal fishes, in terms of the clustering and ordination (MDS) techniques.
Total number of 98 families, 289species and 43,027 individuals were collected. Among which 19 species are newly found in Taiwan, 83 species are commercial fishes. In horizontal, the distribution of fish species is different among these three areas. In vertical distribution, it can be separated into three major groups: 50m, 100-200m and under 400m. The temporal effect on the fish community structure is much more apparent than in Cinshan area, because most fishes in this area are seasonal commercial fishes. Fish fauna at Tahsi is affected more by depth. It is suggested that the three factors affect fish communities from the most to the least are depth, location and time. Furthermore, we compare those major commercial fishes with that of thirty years ago, the size of fishes we caught are getting smaller than before. This is maybe due to the result of over-fishing over a long period of time.
| Identifer | oai:union.ndltd.org:TW/090NTOU0270002 |
| Date | January 2002 |
| Creators | T. H., Wu, 吳宗翰 |
| Contributors | K. T., Shao, 邵廣昭 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 111 |
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