| 英文摘要 |
1a. Evaluate the effect of appointed cease fishing setting up for Larval Anchory Fishery
Abstract:
Larval fisheries in Taiwan use various types of small-sized net deployed in inner coastal zone of less than 200 m offshore with a depth of less than 30 m. In order to reasonably regulate the fisheries, the government had announced a guideline to regulate the fisheries, in which items of allowable fishing, total catches and banned fishing seas are enforced to maintain larval resources in a healthy condition. In the mean while, the guideline allowed the fisheries practices in a maximum period 5-yrs. However, the time-limited for phasing out the practices has been postponed to December 12, 2008 for the reason of fisher's livelihood. One measure of gradually expanding banning-season from 3 months to 5 months or more is proposed to acclimatize local fishers in order to minimize the impedance and sudden harshness. This project attempted to evaluate the effect from the implementation of no-fishing strategy in addition to the previous banning season.
We analyzed historical fishing data including an earlier period (1990-1994) of no regulation and the regulation enforced 8 years (2000-2007). The result indicated that the fisheries regulation took away an average effective fishing effort of 59 from 189 workable days in a year, which mean the enforcement of the regulation down-regulated 31.4% in the size of the fisheries. Within a specific year, during mandatory banning-season (June-August), 54.9% of fishing effort was diminished, and this is also equivalent to 10.6% of effective rate to save the resources. At the same time, the 2008's designated no-fishing measure deserved amount of 13.0% of effectiveness. In total, the two measures took 23.6% of effectiveness in saving the resources.
Regarding to fish species, 11.4% of Encrasicholina heteroloba were benefited, while 54.0% of E. punctifer were escaped from the fishing ground when banning-fishing season was in action, and the designated no-fishing practices added another 11.5% and 2.1% to the two species. For the by-catch species, that regulation measures saved 30.8% of Harpadon species, and 9.3% of Apogon is the dormant effects. The others in order are 20.7% for leiognathid, 12.7% for Saurida, and 9.2% for Sillago species. Namely, banning measure won 13.8% of the effectiveness. As to designated no-fishing period, the most significant effect are from leiognathid species (9.6%0, and the next from apogon (2.9%). In short, 16.7% is estimated from the last conservative measure.
1b. Study on effectiveness of fishing methods and characteristics of by-catch
Abstract
Based on the catch sampling and questionnaire analysis, this study attempted to understand the fishing efficiency and species composition characteristic of larval anchovy fishery by different fishing gear. All the data sets are collected from Kengfan, Fangliau, Wanli and Tansui. The results showed that during spring of 2008, the economic benefit in Kengfan is lower than that during spring of 2007. The average economic benefit of the dip net fishery and the torch fishery is 1,369~5,500 and 9,206~9,793 NT$/day respectively. The catch by quantity of oil of the two fisheries is 0.17~0.33 and 0.75~0.98 kg/l respectively. The average economic benefit during autumn of 2008 is 6,815~27,440 NT$/day.
The compositions and rates of by-catch are varied in terms of time progress and different waters. In the Kengfan and Fangliau water, the rates of by-catch were higher in spring than that in autumn. In Tansui water, the by-catch rate in Oct. is 44.1%. In Kengfan water, the dominant taxa is Gobiidae(25.4%), Leiognathidae(39.6%), Leiognathidae(48.9%), Leiognathidae(58.3%) in April, May, Sep., and Oct. respectively. In Fangliau water, the Leiognathidae is dominant from March to May (65.1~73.3%) during spring. |