The Effect of Angling on Fishes composition for Shuangsi River in New Taipei City
Date Issued
2014
Date
2014
Author(s)
Lin, Hsuan-You
Abstract
Stream closing and fish protection conservation measure has become a trendy stream management in the Taiwan. Most segments implementing stream closing and fish protection show positive trend in restoring stream resources, but the fruitful conservation outcome are facing a question whether the benefiting resources are equitably and reasonably used for sustainability; therefore, to establish an effective management model of stream closing and fish protection in river segment in order to implement rules for the sustainable use of resources has become a particularly important issue.
This study selected Shuangxi River, New Taipei City as the study site, The experiment for this study took place from January to December,2012, hypothesizing the changing of river segment opening for angling will reflected in the minor tributaries, and therefore, by conducting electro-fishing method to collect data for analyzing the species composition and the changes of the numbers of species and population size between different seasons and segments to discuss about the angling behavior’s impact to the composition of fish; angling method is also practically used in fishing permitted segments of the river in early, mid and late stages of the angling permitting duration to discussed the number of species collected in different stages.
The results found that changes in the composition of the fish species, body length of the fishes captured by angling, gradually decreases by different conservation stages, while electro-fishing method has shared the same trend, but for the survey during the restoration stage, the populations of the targeting species for angling trend to restore in numbers, and from the length frequency data also discover that newborn fry has been add into the population, which reveals that the conservation strategy for opening two months a year for angling did not cause significant impact on the population size, which suggest that the stream closing and fish protection policy in Shuangxi River is effective and should be continued.
The average body length of angling target species in this study compared with the results of historical data related to reproductive biology by literature reviewing, regardless of the angling target species collected by electro-fishing method or angling, the average body length of both methods are lower than the range of mature individuals, except Onychostoma barbatulus. This reveals that the angling target species of this basin might face certain unknown factors, causing the body length slightly lower than the mature body length, which might contain a possibility of overfishing without monitoring.
This study concludes that the decease of population size and removing of the larger body size individual, are related to the angling opening period, but without the disturbance impact cause of the other factors, the restoration of population size could affect in two months, hence the existing stream closing and fish protection regulations should be continued. As to current management has no restriction on capture size, this study recommended by changing the current situation for opening two months a year into opening two months every 2 years, in order the let the fish community maintain a stable effective population size. Further researches on the biological characteristics of each species and life history is recommended, especially for the competition, food, resource and biological effects in order to improve the understanding of the fish community stability and the mechanism to stabilize the population structure.
Subjects
封溪護漁
永續
垂釣
過漁
群聚
SDGs
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-103-R99b45030-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):0d4bd8c479a3f4d232efcc837f37f2e7