| Summary: | 碩士 === 國立高雄海洋科技大學 === 漁業生產與管理研究所 === 106 === Abstract
The effects of different lunar phases on the fishing condition of the Chuan-Tin set net fishing ground in the Nan-ao coast, northeastern Taiwan and its five dominant species were studied on the basis of its catch statistics, fishing operation time, tidal current direction and speed during the periods of Jan.-Jun. and Oct.-Dec. in 2015. The assemblage analysis showed that seasonal catch composition of set net can be divided into three groups as Group I (May-Jun.), Group II (Oct.-Dec.), and Group III (Jan.-Apr.), respectively. Based on the value of indices of relative importance (IRI), the first five species were Sphyraena acutipinnis, Auxis thazard, Sarda orientalis, Scomber Australasicus, and Trichiurus lepturus. The results of this study showed that there was no significant difference between the fishing condition and lunar phase at Chuan-Tin set net fishing ground. This phenomenon could also be found in species-specific catch rates. However, the catch fluctuations of set net and its species-specific in relation to tidal currents which relate to lunar phase were found in this study. In general, the fishing condition is better during the periods of current which sea water was flowing to south, but it could be different depending on specific species. The catch rate at tidal current speed about 0.3-0.7 knot was found to be more efficient than that of other speed ranges. Furthermore, the day catches often being better than night catches which implied that the activities of fish groups around the set net in daytime are more active than during the night.
Key words：Otoshi-ami set net, Fishing condition, Lunar phase
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