| 英文摘要 |
Abstract of \"Investigation on Major fishery Resources and studies on Reasonable Regulatiory Devices in the coastal water of Taiwan\": 1. \"Analysis of catch data and fisheries oceanography for Taiwanese precious coral fishery\" : 本計畫為科技保密計畫，故不引入相關資訊，請另參照細部計畫期末報告紙本。 2. \"Studies on the dynamics, utilization and management of flyingfish and flyingfish roe fisheries in surrounding waters of Taiwan\" : 本計畫為科技保密計畫，故不引入相關資訊，請另參照細部計畫期末報告紙本。 3. \"Assessment of mackerel and scad fishery resources in the waters of Taiwan\" : 一、 Blue mackerel belongs to straddling fish stock and is an important commercial fish in the seas northeast of Taiwan. During its life history, blue mackerel has been exploited for several purposes: fish of body length under 17 cm for fresh bait in aquaculture, between 17 and 22 cm as bait for tuna longline fishing, and over 23 cm exported to developing countries as food or other processed products. Mackerel of body length over 30 cm as food for domestic fresh fish market and can be processed as one night salt-dried mackerel. Mackerel fisheries is therefore developing quickly, and the sustainability of its natural resource has been a focal issue for the industry. The present study, based on 13-year data of fishing information of large purse seine (Japanese type) and small purse seine (Taiwanese type), standardized the catch effort, then examined the variation of CPUE. In the meantime we collected fish specimens to study reproductive biology and assess the growth status with von Bertlanffly growth equation (VBGE). Our results showed that in recent years for the blue mackerel the theoretical maximum length and L50 have decreased, growth coefficient has increased, and CPUE has decreased. These changes clearly indicate overfishing of blue mackerel. We also found out that the mandatory fishing moratorium based on the weather and Taiwan tested the fishing moratorium in June 2013 has effectively regulated and improved the production of mackerel fisheries. After the closing of unilateral mandatory fishing moratorium enforced by Taiwan, a short term increase in fishing yield of the Taiwanese fishing vessels was evident. In the meantime fish body length was also increased. The moratorium, which was taken place in spawning season, partly protected spawners of mackerel as well as their newly hatched larvae, and resulted in later increase in recruitment of the population, consequently the increase in fishing yield. We also found short- term moratorium in March or April for 1 week was effective. These results illustrate the positive effectiveness of mandatory fishing moratorium. However, the catch effort is still too high and there is no international management mechanism to enforce the moratorium, therefore, no practical assistance to the recovery of the mackerel resources. 4. \"Research on Mullet population dynamic and management measure\" : 本計畫為科技保密計畫，故不引入相關資訊，請另參照細部計畫期末報告紙本。 5. \"Stock status of loliginid squids in the northern Taiwan Strait\" : 6. \"Monitoring resource fluctuation in Taiwanese Bua Fisheries and reviewing management plan\" : Larval fisheries, being called “Bua” fisheries in Taiwan are commonly found in the coastal areas. The local fishermen seek after engraulid (anchovies) and clupeid (herrings) larvae in spring (Mar ~ May) and fall (Sep ~ Nov). During 1990’s the annual landing was accounted to 1,000 t, while in the last ten years barely 500 ~ 700 t were landed. This annual project keeps on collecting data from Bua practices in order to monitoring the fishery resources and updating annual management plan. A comprehensive logbook collection system has been constructed by Fisheries Agency in 2009, and thus the 2012’s data were the fourth complete annual data complemented into the system. In 2013, we found 10,290 data records, which are 1,049 records surplus to that of 2012 (9,241 records). The dataset included 6,575 boat-trips, and 15,918 net throws; including large-wing, fyke and fork –hand nets. The harvest was summed to 1,130 t and averaged 172 kg boat-trip-1, and the amount valued 204.2 million NTD, with an averaged unit price of 180.7 NTD kg-1. The data collected in spring 2014 is compiled, and will be concluded next project term. In the 2014 spring, it exhibited that the starting date of practice was on April 15 in NE waters, but the fishing condition was far from good. The condition improved on April 20, when 2.8 t was landed in a single day, but it decreased pretty soon, reflecting a poor fishing season. In SW water, the fishing season started on January 9, daily landing could reach 1 t, with scattered 2 t per day. This condition is not as good as the last year, but compared to the NE's, it could still consider acceptable. The Bua catches was composed of 5 major species in NE waters; i.e., Buccaneer anchovy (Encrasicholina punctifer, 39.5 %), Japanese anchovy (Engrailis japonicus, 30.2 %), shorthead anchovy (E. heteroloba, 9.0 %), yellow sardine (Sardinella lemuru, 10.6 %) and Sardinella zunasi (4.0 %); 3 species in NW waters, Buccaneer anchovy (47.9 %), Japanese anchovy (43.6 %) ＆ yellow sardine (Sardinella lemuru, 7.0 %); and in SW waters, Buccaneeer anchovy (46.5 %) and shorthead anchovy (40.0 %). The by-catch percentages were fair (averaged 5.13 %), reflecting a low by-catch rate in 2014’s spring. Finally, we saw recruitment in NE was low in spring, but moderate in SW. Based on long term historical data, we expect the resource should recovered to moderate level of higher than 1000 t per year. 7. \"Studies of stock dynamics and assessment for cutlassfish\" : 本計畫為科技保密計畫，故不引入相關資訊，請另參照細部計畫期末報告紙本。 8. \"Survey and assessment for crab fisheries resources in north of the Taiwan Strait and off Penghu\" : 一、The purpose of this project is to survey and assess the crab resources in north of the Taiwan Strait and off Penghu. The main tasks include (1) to survey the dynamics of fishing boats aimed at the crabs in north of the Taiwan Strait and off Penghu, (2) to examine the main species composition of crabs from north of the Taiwan Strait and to design the logbook and develop the retrieval channel of logbook for collecting and analyzing spatiotemporal distribution of fishing effort, catch and CPUE, (3) to measure the crab wide for obtaining the size-frequency data and to analyze the reproductive biology of main crab. 二、The results showed that (1) the main fishing areas were between 25 and 28 degrees north and between 121 and 125 degrees east; (2) the main fishing species were Charybdis feriatus, Portunus sanguinolentus and Charybdis natator in the northern waters of Taiwan Strait, and the most abundant species is Charybdis feriatus; (3) the crab width of Portunus sanguinolentus was between 70 and 180 mm, and the smaller crab was found from June to Aug and Dec.; the crab width of Charybdis feriatus was between70 and 180 mm, and the smaller crab was found all year around; (4) the CPUE values of Charybdis feriatus were lower (beneath 20g/pot) from Mar. to Jul, one increased from Aug. to Nov, and decreased from Dec. ; the CPUE values of Portunus sanguinolentus were lower (beneath 10g/pot) from Apr. to Jul, and one also increased from August; (5) no or rare complete mature individual was shown in Jan., Sep. and Oct. for Portunus sanguinolentus, but there are some ones was found in the other months., the most proportion of the immature stage and early-developing stage were found from Nov. to Oct., but the minor proportion of the ones was found in Jul. and Aug.; no or rare complete mature individual was shown in March and from Aug. to Dec. for Charybdis feriatus; the most proportion of the immature stage and early-developing stage were found March and from Aug. to Dec., but the minor proportion of the ones was found in Feb. and Jul. ; (6) the first maturity length (L50) for for Portunus sanguinolentus and Charybdis feriatus were 9.854 and 8.538 cm, respectively. |
