- 期刊
- OpenAccess
Fishing Capacity and Conditions of Light Fishery under Different Fishing Light Intensity
在不同集魚燈光強度下火誘網誘集效果之研究
摘要
本研究於2003年6月19日至10月28日期間，租用民間棒受網漁船，在台灣北部海域中以6組不同燈光功率之水上集魚燈，進行116網次之棒受網漁撈作業實驗，以探究台灣北部海域棒受網漁業在不同集魚燈光功率之誘集效果。結果顯示，在6種不同集魚燈光功率下，其CPUE有隨燈光功率之增加而增加，其中在80kw集魚燈光功率下，棒受網漁業之誘集效果似乎已達飽和。此外，由116網次漁撈實驗中，主要漁獲魚種鎖管、白帶魚、剝皮魚及其他魚種，分別在6種不同集魚燈光功率下之重量組成比率則顯示，在較高的集魚燈光功率下，白帶魚及剝皮魚會有較佳之誘集效果，但鎖管則是在較低的燈光功率下，會有較佳之誘集效果。再者，由116網次之漁獲魚種組成，經群集分析的結果，則可歸納出A（鎖管群）、B（白帶群）、C（鎖管與白帶混雜群）、D（剝皮魚群）及E（多魚種混雜群）等五種類群之魚獲組成，其中在A類群網次中，鎖管之平均CPUE分別在20及80kw時有較高之漁獲水準，且由鎖管外套膜長之分布則發現，外套膜長在80 mm以下之小型鎖管，在較低之燈光功率下（40 kw以下）會有較佳之誘集效果，反之大型鎖管則是在較高之燈光功率下，會有較好之誘集效果。綜上可知，棒受網主要標的魚種鎖管之CPUE，除受燈光強度物理因子之影響外，亦會受生物因子之影響，因此其漁獲量並未随燈光功率之提高而有顯著增加之趨勢。
並列摘要
A total of 116 nets of halogen light fishing under 6 classes of light intensity were conducted in the northern waters of Taiwan during June 19 to October 28, 2003. The average CPUE of 6 classes of light intensity showed that the CPUE was increased by the increasing intensity of fishing light and reached a peak under 80 kw condition. Cluster analysis indicated that the species composition from the 116 fishing nets could be divided into five major groups-A (squid group), B (hair-tail fish group), C (squid and hair-tail fish mixed group), D (file fish group), and E (multi-species group). The relationship between CPUE and light intensity was quite different in each group, probably due to the different species composition under different light intensity. In group A, the average CPUE of squid was not increased by increasing intensity of fishing light, it had the higher fishing capacity under 20 kw and 80 kw. In groups B and D, the average CPUE was increased by increasing intensity of fishing light. In group C, the average CPUE of hair-tail fish was also increased by increasing intensity of fishing light, but the average CPUE of squid was decreased by increasing intensity of fishing light, probably due to the aggregation of squid was discouraged by the presence of more hair-tail fish, a predator of squid, under higher light intensity. In group E, there is no relationship between CPUE and light intensity, due to the complexity in its species composition. Compared with the distribution of dorsal mantle length (ML) of squid, which was the major target spices of light fishery in Taiwan, we found that the smaller squid (ML＜ 80 mm) had higher CPUE at lower fishing light intensity (below 40 kw) than at higher intensity (above 60 kw). Conversely, for the larger squid (ML ＞80 mm), CPUE is better at higher capability of fishing light intensity. This result suggested that the CPUE of squid was influenced not only by the physical factor (capability of fishing light), but also by the biological factor such as body size, presence of predator, and so on.