| 英文摘要 |
Abstract of "Studies on the stock assessment, management and development of fisheries resources"
一、"The 2006 year seminar on the fishery resourcesassessment, management and utilization":
This study was tried to call a seminar for presenting the running research supported by the Agriculture Council of Executive Yuen. This study was tried to reestablish the databank of seaweed bed and coral reef, and to evaluate the situation of coral reef and protected areas in the waters of Taiwan. The interested fisheries such as the set-net fishery, bottom-trawling fishery, the recreational fishery, were also investigated for understanding several specific species for more details of population dynamic, resources analysis or biological research, which was focused on whole fish community and the structure, function of ecosystem, and the potential and sustainable development in the coastal waters of Taiwan.
二、"Studies on the life history traits and habitat use of larval fishes in the estuaries of Taiwan":
Biomass of estuarine larval fish is an important indicator for predicting fishing resources. Therefore, to understand their species composition and abundance is essential for fishery management. The recruitment mechanism of the larval fishes from spawning ground to estuaries is not clear. This project will target on the recruitment mechanism of the progy which is a dominant species in the estuary of Taiwan. We will calculate the daily age and growth rate of the larval progies by reading their otolith daily growth increments and analyse the otolith Sr/Ca ratios and trace element composition to trace their migratory history and habitat use. We expect to understand the spawning season and early life history of each progy species, and the knowledge will also offer important references for fishery resources assessment and habitat conservation and management.
三、"Stock assessment of black marlin in the waters off Taiwan":
Age and growth of black marlin (Makaira indica) in the waters off eastern Taiwan were studied from counts of growth bands on cross sections of the third spine of the first dorsal fin. Length and weight data and the dorsal fin spines were collected monthly at the fishing port of Shinkang (southeast of Taiwan) from July 2004 to April 2006. In total, 923 dorsal fins were collected, of which 874 (95%)(187 males and 687 females) were aged successfully. Trends in the monthly mean marginal increment ratio indicated that growth bands formed once a year. Growth differed significantly between the sexes; females grew faster and reached larger sizes than did males. The maximum sizes in our samples were 368.2 cm LJFL for females and 261.5 cm LJFL for males.
四、"Migration route and stock survey on Ocean Sunfish in the eastern waters of Taiwan":
We have understood many subjects more clearly after our study from 2003 to 2005.There are including resource variation of ocean sunfish, and age and growth, migration route and habitat of sharptail mola. Many people care that the numbers of catch in sharptail mola in 2005 are lower than before. Then we have focused on two subjects, migration route and resource variation of ocean sunfish, in this year. One PAT tag has been used to estimate the migration route of sharptail mola at November 8, 2006. The total length and weight of marked fish is 131 cm and 80 kg. The tag recorder will release and start to transmit data at February 11, 2007.
五、"Research on flyingfish fisheries in the coastal waters of eastern Taiwan":
The GSI from the most commonly collected three species in Ilan and north-eastern Taiwan all reached their highest value in June which corresponds to the harvest season in the vicinity of the waters. Hence the study confirms their spawning season during this time of the year. The individual fecundity estimates from the four species are as follows: 50363 in margined flyingfish, 45809 in stained flyingfish, 31165 eggs in white-fin flyingfish, 11803 in yellow-wing flyingfish. The information would be helpful for the flyingfish fisheries management in the future.
六、"Cultivation for the exploitation and utilization of economically-important seaweeds along the coast of Taiwan":
Regarding the growth of seedlings from pore germination, it was found low temperature and short light period were favor for the growth of Gelidium seedlings, especially the plain-seawater without nutrients. Enriched medium usually promoted the epiphytic diatoms and disturb Gelidium growth.
Outdoor growths were also compared between the cotton, Nylon and hemp threads for the hanging of thalli fragments horizontally or vertically at early or late growth seasons. The experiments were conducted at two places, Taipei County Hatchery and Ilan Private abalone grow-out tanks and the result were compared.
七、"Studies on tagging and marking methods and their released effects for mass fish juveniles":
The fry hatchery-reared and released was an important part of sea-ranching in order to enhance the natural fisheries stocks. The marked fish released and captured were used to study the population size, distribution, movement, and assessment of wild population. Most marking methods, for instance fin-clipped, branding and tattoo, etc. were expensive and time-consumed for mass marking of released fry. Therefore, it is important to find the methods of mass-marking with time-saving, low cost and detected easily. The juveniles of black porgy（Acanthopagrus schlegeli）with 4.0cm-8.5cm using the methods of mass-marking were carried out in a hatchery in Taoyuan county, and then released to the sea water. The results were as follows.
We found that the double marking method, i.e., the fish sprayed with fluorescent pigment spraying on the skin of fish after fed with tetracycline was a suitable and good marking method for juveniles of black porgy. About one hundred and eight thousands juveniles of black porgy were marked and released to sea water in Baishatun, Moiland county during July 21- September 23. Total 41 marked fishes had been recaptured up to present October, 2006. The stock size in the water was estimated as 1,411,727 (95% CI = 997,952-1,825,502) and 1,446,040 (95% CI = 1,437,578-1,454,502) by Petersen and Schnabel methods, respectively. The stock contribution of released black porgy was 8.7%.
八、"A study on Taiwan coastal fisheries GIS establishment and its application":
Fishing activities cover almost all the waters and coastal zones of Taiwan. Without any doubt, the data collected during fishery process, such as oceanographic investigation, catch and effort statistics and commercial landings and etc, are important sources for fishery management and research. However, the availability of the data is always poor due to lack of systematic compilation. To reach a mutual development of fishery and multi-purpose utilization of coastal zones, it is basic requirement to efficiently manipulate fishery information such as species, quantities, seasons, fishing grounds, protection zones, management scheme and etc. In this three-year project, we aim to establish a GIS for coastal fishery so as to extend spatial property of FA fishery statistic system through integration of coastal fishery and habitat data. In the last year of the project, the system and maintenance developed will be transferred to Fisheries Administration. All related manuals are also compiled for smooth operation in the future.
九、"Study on the ocean primary production in surrounding water of Taiwan":
This study aimed to investigate the seasonal changes of the primary production, chlorophyll a and nutrients surrounding Taiwan. The nutrients, including nitrate, phosphate and silicate changed with season. All the nutrients in autumn were higher than summer’s. The primary productions had a high relationship with chlorophyll a. The surrounding water of Kueishan Island had the highest primary production. In this area, the primary production in summer and autumn were 8.81 and 6.92 g C/m2/day, respectively. The primary production in Northeast area, East area, Southwest, Penghu islands and northwest area were averaged 1.007、0.217、0.519、0.567 and 0.822 g C/m2/day in summer, respectively. Following the above area, the primary production averaged 1.195、0.564、1.012、0.331 and 0.616 g C/m2/day in autumn, respectively. Furthermore, following above area, the chl a averaged 0.138、0.070、0.107、0.058 and 0.078 mg/m3 in summer, and 0.255、0.198、0.336、0.167及0.156 mg/m3 at autumn, respectively. |
