碩士 / 國立海洋大學 / 漁業科學學系 / 90 / Abstract
Yellow sea bream is one kind of highly valued fish. In the northern Taiwan, the traps were used to catch yellow sea bream around Peng-Jia Yu. There is a little report about catching capabilities of traps for yellow sea bream, and difficult to find the literature about behavior of the trapped yellow sea bream. In additional, the puffer fish not only has non-economic value in Taiwan but also attacks the trapped yellow sea bream in the trap. Therefore, it is necessary to find a way to improve the design of the traps for yellow sea bream in order to reduce puffer fish by-catch. Furthermore, the smaller mesh size of traps affect yellow sea bream resources. To determine the catching capabilities of traps for yellow sea bream, a series of experiments were carried out both in the laboratory and the field.
In this studying, the results indicate that the fish would initially enter the trap opening that was attracted by bait placed in the trap. After finish feeding on the bait, the fish tends to swim backward and in an attempt to escape from the trap. At the meantime, the trapped fish tends to be pushed further into the trap by its fellow fish that intends to feed on the bait. If the yellow sea bream were too big to maneuver in the trap opening area, it would be impossible for the bigger fish to escape from the trap. Also, when the trap were lifted or moved, the yellow sea bream, which were at the trap opening area, would be frightened and swim further into the trap and captured. The experimental results suggest that puffer fish by-catch could be substantially reduced by inserting a piece of wire at the opening of the tunnel at the entrance of the trap. And in order to increase yellow sea bream catch, baits must be placed not only at the front part but also at the end of the tunnel. The bait at the end must stick out to lure the fish to come in in-depth. Furthermore, the optimum mesh sizes for yellow sea bream were found to have a diagonal distance of the mesh opening greater than 59.3 mm and 63.5 mm, respectively. It could allow those yellow sea bream whose fork length smaller than 15 cm and 16 cm free from trapping, while 30 percent of yellow sea bream mature with a fork length of 15 centimeters and 70 percent with a fork length of 16 centimeters. The results suggest a way of improving the design of the traps for yellow sea bream and in turn it leads to a reasonable utilization of yellow sea bream resources.
| Identifer | oai:union.ndltd.org:TW/090NTOU0451010 |
| Date | January 2002 |
| Creators | Jen Yung Wang, 王仁遠 |
| Contributors | Chuan Hung Ho, 何權浤 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 0 |
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