FRA

Diagnostic DNA markers based on the restriction fragment length polymorphism (RFLP) and nucleotide sequence analyses on two regions of the mitochondrial DNA (cytochrome b gene and flanking region between ATPase and COⅢ genes) were obtained using representative specimens of Auxis rochei, A. thazard, Euthynnus affinis, Katsuwonus pelamis, Sarda orientalis and all Thunnus species. These DNA markers were applied to a total of 936 scombrid larvae and juveniles ( 9 mm to 186mm in standard or fork length) collected by a mid-water trawl operated in the tropical and sub-tropical western Pacific during 1992 to 1998. Four Thunnini species (K. pelamis, T. alalunga, T. albacares, and T. obesus) were observed in the samples from the open water area (2°N-15°N, 135°E- 157°E), while eight species (A. rochei, A. thazard, E. affinis, K. pelamis, S. orientalis, T. alalunga, T. albacares and T. thynnus orientalis) were observed in the samples from the island associated area (24°N-30°N, 123°E-131°E). Gill rakers were not fully developed in the juveniles smaller than 60mm in fork length, and may not be useful for identifying the species of Thunnus and Auxis.

We have developed a database system for the observation records of the small bathythermograph system SBT-500 and their related data during longline operations. The purpose of this database is to summarize and hold SBT-500 data and related data such as cruise, longline operation type, fishing gear type, biological data by species, calibration data for the sensors, and oceanographic data in order to assist analyses for studies in various fields. These data are stored in individual tables or directories in a personal computer and linked together. Using this database, analyses of 1） oceanographic conditions, 2） hooking depth, temperature and time of captured species and 3） underwater shape of longline gear can be conducted, not based on temporally and spatially limited small data sets but instead using a large amount of linked data. So far there are over 20,000 records stored, and once more data are gathered, even more reliable analyses will be possible.

In coastal fishing villages of Japan, the decrease in number and aging of fishermen and the subsequent decline in the economic vitality has become remarkably. Therefore, it is necessary to enforce activation measures to respond to the regional characteristics to help re-invigorate such areas.
　I did a chief ingredient analysis using six indexes related to the economic performance and six indexes related to fishery performance. As a result, two chief ingredient scores to represent the vitality of the fisheries and economic vitality were calculated. Using these scores, Japanese coastal municipalities were divided into five types. In these types, municipalities where fishery vitality is low and economic vitality is low “vitality low rank type” accounted for 30% of the total coastal municipalities. I considered measures for regional activation through the assessment of the characteristics of each type by various statistical indices. From these results, fishing ground preparation by the establishment of artificial reefs and resources management are valid for a fishing village activation for the “vitality low rank type”, because many coastal fishermen are in this type. Furthermore, the “economic vitality advocacy type” that fishery vitality is low and economy vitality is high, which are markedly distributed adjacent to urban environs, and activation occurs by interchange with the city. It became clear that in addition to data from other investigations, the above analysis based on many indices was effective to enable initiation of regional activation policy applicable to each regional characteristic.

As one of the regional activation methods, although the fishing ground creation by artificial reef establishment is enforced with each area, examples that a clear effect is observed are comparatively few. This was caused, in part, by the lack of appropriate management of fishery resources after their establishment. I did an example analysis of an artificial reef in the Fukushima Prefecture, Soma District here. Fishermen do resource management voluntarily and restrict the fishing term, fishing method with the artificial reef range with this example of artificial reef establishment. It became clear that this attained a large part for an effective utilization of an artificial reef. Furthermore, it is not long since an artificial floating reef was established, although the actual situation solving of utilization, a management evaluation and an economically effective evaluation were not done sufficiently until now. I analyzed it considering the Kagoshima Prefecture, Amamioshima Sea Region as an example here. The result, establishment of an artificial floating reef brought about a direct effect due to an increase of the catch quantity and revealed many indirect effects such as a profit increases to the fisheries cooperative association, in oil usage reduction for fishermen, operating hours shortening, and the extension of the fishing term. The result, artificial floating reef produced about a 2 ～ 5.6-times viable effect of the cost required for its establishment and maintenance. At distant islands, fisheries play a significant part of the regional economy. While bottom fish resources decrease, for the effective exploitation of migratory fish the establishment of a artificial floating reef is valid as a regional activation measure.

Fishing villages have various valuable regional resources that are not available in a city. By an interchange, cooperation with urban residents by a valid application of regional resources, a trial to plan an activation of a fishery area is done in many fishing villages. This section examines and discusses an example of the traditional “Sailing Trawl Fishery” used in Lake Kasumigaura and Lake Kitaura. I evaluated a non-utility-value against regional residents and recreational benefits for embarkation persons (urban residents), that an amenity of a sailing trawl fishery gives, and large values were measured. Next I did a statistical analysis and questionnaire survey analysis about a fishermen's hostel to be able to become a nucleus of interchange. The number of people and variety of fishing activities that 1 fishermen's hostel can provide is limited. However, it can provide for the various needs of urban residents, by utilizing the fishing village whole area and be related with the activation of the fishing village whole area. Further, I analyzed about fishing village activation by experience fishery (practical introduction) to fishing methods. As the establishment of special facilities are unnecessary for an experience fishery, a fishery person can easily do. In recent years, the number of participants for an experience fishery has decreased due to the economic decline. On the other hand, schools doing fishery experience as a general learning opportunity has increased. Therefore, from now on, an increase in the number of times can expected with relation to school excursions. In fishing villages comparatively close from a city, an increase of day trips by elementary schools and junior high schools can be expected. On the other hand, in distant islands, for school excursion it is necessary to utilize fishermen's hostels for the development of the range of possible experiences a fishing village to become available as a substitute when the weather is bad also, though it is necessary to prepare for the operation. With increasing local demand, a positive PR to schools and a travel agent of another prefecture becomes necessary for arranging school parties, and cooperation with the sightseeing society and the town office person in charge becomes important. Last, I assessed the effect to a fishing village of recreational clam digging at Aichi Prefecture, Kira Town and estimated the effect to urban residents. Clam digging brought about large profits to the fishermen ferrying visitors to the Kajishima Island as well as to the fisheries cooperative association. When I estimated the recreational benefits to visitors by TCM (Travel Cost Method), an average of 4,900 yen per person totaling entirely 36 million yens was estimated. This amount was almost equal to the Manila clam catch (38 million yens) per year at the Kira Fisherman Cooperative Association.