||Abstract of "Investigation on Major fishery Resources and studies on Reasonable Regulatiory Devices in the coastal water of Taiwan: with emphasis on Precious Coral, Flyingfish and Flyingfish Roe , Mackerel and Scad, Mullet, and Loliginid squid.":
1. "Studies on the utilization and management of flyingfish and flyingfish roe fisheries in coastal waters of Taiwan" :
2. "Assessment of mackerel and scad fishery resources in the waters of Taiwan (Primary in the north east area)" :
Blue mackerel belongs to straddling fish stock and is an important commercial fish in the seas northeast of 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 11-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. 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.
3. "Analysis of catch data and fisheries oceanography for precious coral fishery in Taiwan" :
Precious corals are of highly economic values and of significance in religion and culture. They have been commercially exploited for many centuries in the Mediterranean and for almost one century in the Northwest Pacific. Although the precious coral fishery in Taiwan dates back to the 1920s, relevant studies on biology and ecology of resources are relatively scarce. The management of the precious coral fishery in Taiwan was officially instituted in January 2009, when data on the catch and effort of the fishery were recorded. In this study, the catch-effort data of the fishery between 2009 and 2013 were examined to explore the temporal and spatial patterns in composition and abundance of Corallium and Paracorallium spp. around Taiwan. According to the regulation, the objectives of this study are (1) to collect and maintain the catch and effort data of precious coral fishery of Taiwan, and preliminarily analyse the distribution patterns spatiotemporally; (2) to identify the target species and bycatch species, analyse catch composition and morphormetric measurements; (3) update and maintain catch and effort database.
A. Fisheries data analysis
The annual number of issued licensees was around 60 and landing ranged 2.9 to 3.5 tons between 2009 and 2012. The number of vessel was 60 with a landing of 2.3 tons in 2013 (September). The fossilized colony was predominant (57~78%) in the production, while live colony was lesser than 5%. The proportion of live colony was 2.1% in 2013 (September). Momo coral was predominant in the total production (＞63%) and in production of live colony (＞60%). The fishing effort (vessel-day) mainly located at designated fishing ground (DFG) A (53~64%), followed by DFG-B (10~22%). The spatial distribution pattern of total production was similar to those of the fishing effort. Production of live colony was major from DFG-E (48~82%), followed by DFG-A (15~45%). A significant seasonal movement was found for spatial distribution pattern in fishing effort. Monthly catch rate of total production showed seasonal pattern. Temporal variation of production of live colony was different for different species in each DFG. The occurrence rate of live colony was increase (from 21% to 34%) in 2010~2012, but also did the standard deviation. The high proportion of fossilized colony in the production showed not only low efficiency of the non-selective gears in the fishery, but also the possibility of low abundance for live colony in the DFGs. The management of sessile animals, such as corals, should consider not only sustainability of the population in structure, but also in functions in the ecosystem which will achieve the targets in fisheries management and conservation.
B. Biological data analysis
In 2013, the result of present survey indicated that three Coralliidae species including Corallium elatius, C. konojoi and Paracorallium japonicum were collected by precious coral fishery resembling the result in the past year. In the non-fishery region, C. sulcatum was recorded near the southern region of Orchid Island. In this year, we do not find any new Coralliidae species. Observers went to zone A for 17 times, zone B for 8 times, zone D for 3 times and zone E for 3 times. The major harvested species in the above four zones is C. elatius and live colonies were occasionally caught. The only live colony of P. japonicum was collected from zone A. In zone A, the collection records were composed of 292 corals, and only 20 of them were live colonies. In zone B, 56 corals were collected, and only 1 was live colony. In zone D, there were 2 live colonies recorded among the 17 caught corals. In zone E, the collection data of 88 corals were recorded and 10 of them were live colonies. Comparing with the data in last year, the ratio of live colonies was slight increase in zone A. We still have to continue monitoring the variation of precious coral resource. For by-catch species, 4 families and 4 species in Mollusca, 5 families and 8 species in Crustacea, 7 families and 15 species in mesophotic corals, 2 families and 2 species in fishes in addition with other echinoderms and sea stars were identified from by-catch. It is the first time that we got data from zone D and we still do not have data from zone C. We have to strive for getting fishery data from zone C to get a more complete view of precious coral fishery.
4. "Research on Mullet population dynamic and management measure" :
5. "Stock status of loliginid squids in the northern Taiwan Strait" :
Resources of squids became less and less, thus lead to the decrease of squid production. Currently, the most researches of squids focused on the relationship between catches of torch-light fishery and fishing environments, as well as biological study of squids which caught by torch-light fishery. Trawl fishery is also one of the main fisheries that caughtes squids. The results showed the distribution range of mantle length in trawl fishery (1.8~40.82cm) was wider than the range of torch-light fishery (2.1~32.9cm). The sex ratio showed the squids caught by torch-light fishery had more males with significant sex difference. The monthly variation of GSI showed that both area of the male squids had a peak value in spring and autumn. In addition, the results of mantle length at 50% sexual maturity excluding spring showed the squids caught in trawl fishery were bigger than torch-light fishery. Exponential and power growth models explained the fit to the size-at-age data to a similar extent.
Alternatively, to observe the he sword tip squid sample in the northeastern water of long-term changes. And the year of average mantle length almost 90mm are not change more in 2001 to 2012. The average of weight is clearly go down in 2001 to 2007. But, In 2008 get high and in 2009 to 2011 also decline. In terms of the abundance index ,it begin period joined by 2002 to 2006 and part of year in which it is added.
The activity of squid half of 2012. To catch the fisheries of squid include trawl fishery, gillnet fishery, torched-light net fisheries, danish seine net fishery, porgy and miscellanous fish long line, pole and lines boote, and troll line fisheries.It has 236 sample vessels totally. Among the catch of squid, the trawl fishery catch 251ton and torched-light net fisheries catch 224ton. The CPUE of vessels concentrate in northeastern, west and Penghu waters.Then the distribution of northeastern water is the most widely. The distribute of torched-light net fisheries’s operation is extending from south of 26°N to west waters ,and distributed all the western waters. And the operate of pole and lines boote is mainly in the waters off Penghu. The catches and effort’s distribute is similar in offshore and coastal fisheries. However the CPUE’s waters of trawl efficiency is highest from part of south 25°N to Yun-Chang Rise.
The fishing lamps of offshore and coastal fisheries is used overview then the useful part is in northeastern of Taiwan ( mean lamp 44). And the used of ton class emerges of exponential increase, CT0 to CT6’s average lamp are total in 10.4 - 98.1
Keywords: squids, waters off northeastern Taiwan, trawl fishery, t orched-light net fisheries,