National Tuna Fisheries Report of Japan as of Miyabe, N., M. Ogura, T. Matsumoto and Y. Nishikawa

SCTB17 Working Paper NFR 11 National Tuna Fisheries Report of Japan as of 2004 Miyabe, N., M. Ogura, T. Matsumoto and Y. Nishikawa Fisheries Research Agency National Research Institute of Far Seas Fisheries (NRIFSF) 5 Chome 7-1, Orido, Shimizu, Shizuoka 424-8633, Japan July 2004

National Tuna Fisheries Report of Japan as of 2004 Miyabe, N., M. Ogura, T. Matsumoto and Y. Nishikawa Fisheries Research Agency National Research Institute of Far Seas Fisheries (NRIFSF) 5 Chome 7-1, Orido, Shimizu, Shizuoka 424-8633, Japan 1. Introduction This paper describes recent trends in the Japanese tuna fishing activities (longline, pole-and-line and purse seine) mostly in the central and western Pacific Ocean (WCPO, west of 150W). Brief fishing report for each fishery is given for 2003, and fleet, fishing effort and catch statistics are also included. Purse seine catch statistics are updated to 2003 but it is not possible to provide them for longline and pole-and-line fisheries as the current level of logbook compilation is not yet enough to make the estimation for that year. Catch statistics of boat smaller than 20 gross tonnages (GRT) for longline and pole-and-line, which is not covered by the current logbook system (pole-and-line, troll, etc) or insufficient to do so (longline), are not compiled by the NRIFSF but referred to the publication of the Statistical Division of the Ministry of Agriculture, Forestry and Fisheries (MAFFJ 1954-2002), and presented in this paper. In addition to the above-mentioned three major tuna fisheries, there are miscellaneous gears catching tunas. Among them, the largest catch is made by the coastal troll fishery whose recent annual catches are about 10,000 MT, 2,000 MT and 300 MT for skipjack, yellowfin and bigeye, respectively. Remaining catches other than this fishery is very minor. 2. Trends in fleet size Table 1 and Fig. 1 show the historical changes in number of Japanese tuna boats actually engaged in fishing by type of fishery and vessel size class. Data are available since 1953 (MAFFJ 1954-2003). For the longline fishery, larger than 100 GRT vessels includes those operated in the outside of the WCPO, but currently there is very few 100-199 GRT boats operating in the outside of WCPO. Most of the boats larger than 200 GRT are operating in the waters outside of WCPO. All other categories operated in the WCPO. The number of longline vessels of the largest size class (over 200 GRT) had been nearly constant since the late 1960s except in 1982 and 1999 when a reduction of fishing vessels took place by about 20 % of that category. The latter reduction was implemented in accordance with the agreement at the FAO s International Action Plan on management of fishing capacity. Vessels of the other categories indicated considerable fluctuation up until the early 1980s but all indicated strong decline at least during the last 13 years. The vessels of 20-49 GRT disappeared in recent years. The total number of longline vessel in 2002 was 1442 which is 421 vessels (23 %) less than that of 10 years ago. In the case of pole-and-line boat, all size classes exhibited a considerable decline including the largest size category, in which case it was 279 in 1975 but now there is only 48 vessels left. Similar to longline vessel, 20-49 GRT size vessels were nearly eliminated from the fishery in recent years. On the contrary, 100-199 GRT class vessels are gradually increasing after a sharp drop which took place in the 1970s. Total number of vessels larger than 20 GRT in 2002 was 152, 86 vessels or 30 % less than that of 10 years ago. Purse seine vessels, which operate in the equatorial waters of the western and central Pacific, are greater than 200 GRT (most of them are 349 GRT), and 50-150 GRT class boats operate in nearshore Japan north of 20N. While the number of vessels of the latter size category decreased during the late 1980's, there has been no change in recent 7 to 8 years. The number of distant water purse seine is 35 in 2002, which has been nearly stable from the early 1980's. 3. Trends in catch and effort 3. 1. Longline fishery Latest available statistics are provisional 2003 data for those boats larger than 20 GRT. Fishing effort and catch in number and weight of tunas (albacore, yellowfin, and bigeye tunas), swordfish and billfishes (striped marlin, blue marlin, black marlin, sailfish and shortbill spearfish) caught by the Japanese offshore and distant water longliners in the WCPO are shown in Table 2, Figs. 2 and 3 for the years 1971-2003. Since the major vessel size in the WCPO is 50-199GRT class, the annual trends in fishing effort and catch were similar to the trends in the number of boats of that category. However, the decline of catch for that category was less pronounced as the smaller boats in the same category have been eliminated. Total longline fishing effort (in number of hooks) has decreased steadily since a peak in 1981 (Fig. 2, bold line at the upper panel). The fishing effort in 2003 was 126 million hooks which is 23 % lower than 10 years ago. The area of effort reduction appeared to have occurred in the waters around Japan and western tropical Pacific as shown in Fig. 2. Among the species caught, albacore and swordfish did not show any decline while the other 1

species indicated continuous reduction especially after 1981. The yellowfin catch was at a peak during the late 1970s and the early 1980s and started going down soon after. Bigeye catch followed this trend in more recent years beginning in the early 1990s. The billfish catch more or less reflected the decreasing trend in the fishing effort. Annual distributions of fishing effort for 1960, 1970, 1980 and 2002 are shown in Fig. 4 and the quarterly effort distribution in 2002 is shown in Fig. 5. The fishing effort has been located in the wide area of the WCPO except for south of 10S and east of 180 meridian. The fishing grounds are located in east-west direction off Japan to Hawaii, equatorial area between 10S and 15N and off Australia. Recent annual and seasonal patterns in the effort distribution have not changed so much, but the overall area of fishing appeared to be contracted and the fishing effort in the western side (west of 150E) have shown a large reduction. Distributional patterns of the catch by species for boats larger than 20 GRT (Fig. 6) are shown for the entire Pacific, and they are classified into several clear patterns (swordfish targeting near Japan, albacore targeting in the middle latitudes between 10-30N and tropical tuna (mostly bigeye) targeting in the equatorial waters). Catch composition for this fleet and that for boats smaller than 20 GRT in 2002 (Fig. 7) indicated that the largest component was bigeye (44% and 36%, respectively) followed by yellowfin (22% for both) and albacore (19% and 20%). These tunas accounted for nearly 85 % of the total catch. Geographical distribution of fishing effort and catch composition for the coastal longliners (less than 20 GRT) were shown in Figs. 8 and 9. Fishing area is more confined to the western Pacific and north of the Equator than the larger longliners in size. The catch composition indicated that the proportion of swordfish appeared to be higher and bigeye is lower (Fig. 7) in this component of the longline fishery especially in the nearshore of Japan. 3. 2. Pole-and-line fishery The catch and effort statistics in the WCPO by the Japanese pole-and-line fishery (larger than 20 GRT in vessel size) are shown in Table 3 from 1972 to 2002. Catch and effort decreased gradually throughout 1980s with a peak being around the late 1970s. After 1991 they were almost stable. Total yearly catches in 1970s and early 1980s were from 250,000 to 300,000 MT and were around 150,000 MT in 1990s and later. Skipjack occupied the major part of catches being followed by albacore and yellowfin. Number of fishing days exceeded 60,000 days in 1970s but it is now slightly over 20,000 days. Number of poles used also peaked at 1977, and were more than 1,200,000 before 1982 except in 1972. Then, it decreased to 400,000 poles level during the 1990s and thereafter. In 2002, the number of fishing days and poles decreased slightly from 2001. Total catch in 2002 was higher than those in previous years amounting at 144,637 MT (Table 3). Catches of skipjack, yellowfin and bigeye tunas in 2002 were 90,466 MT, 2,501 MT and 1,714 MT, respectively (Table 3). Skipjack and yellowfin catches were lower than those in 2001. On the other hand, albacore catch increased to 49,433 MT, 1.7 times higher than that in 2001. Seasonal fishing ground movement was shown as the distribution of fishing effort (the number of poles in 1x1 degree area) in 2002 by quarter (Fig. 11). The fishing grounds move from southwest of Japan to northeast as the time progresses. In addition to these fishing grounds around Japan, north of the North Equatorial Current area was also important fishing ground for this fishery in 1st, 2nd, and 4th quarter of the year. In 2nd and 3rd quarter fishing grounds off northern Japan expanded to further east of 175E. There was no operation in the tropical waters south of 20N in the 3rd quarter. Typical seasonal fishing ground by vessel type was as follows; The distant water vessels (larger than 300 GRT) fish in the tropical waters and the North Equatorial Current area from late 4th quarter to early 2nd quarter, and turn to far north to the area east of 150 E where they target on albacore during June to October. Fishing ground in sub-tropical area east of northern Mariana Islands was the starting area of fishing for the greater part of the offshore vessels (smaller than 300 GRT) in February. Then, this fishing ground gradually moves northward in May and June, and the nearshore area just southeast of Tokyo forms a good fishing ground for these vessels. From July to December, off northern Japan 35N-41N west of 155E, so-called Tohoku area, becomes a major fishing ground around Japan. The fishing ground in the Nansei Islands, southwest of Japan is for the other offshore vessels operating with anchored FADs. The Izu Islands area, south of Tokyo is also fished by some offshore vessels. Almost all fishing ground except for further northeastern area, skipjack has been the major target species and most of the yellowfin catch comes from the Nansei Islands area. 3. 3. Purse seine fishery This fishery had started on an experimental basis during the late 1960s, and has expanded over the following 20 years (Table 4 and Fig. 15). The majority of the catch has been skipjack which accounted for more than 70% of the total catch. Total catch has increased to more than 150,000 MT since 1983 and stabilized to nearly 200,000 MT after 1990. Fishing effort (days fishing) has also shown a similar trend but has been stable since 1983. Fishing grounds in tropical area during 2003 were formed in east-west direction in the wide area of the WCPO (10S-8N, 135E-180 in Fig. 16). This fishing area was different from 2002 as the fleet operated in the west of 150E during the first half of 2003 with an extraordinary good catch of skipjack. This area has not been fished extensively since 1996. During the latter half of the year, most of the effort was exerted in the eastern part of the WCPO between 150E and 180. In the coastal waters around Japan, the fishing season of the Pacific side started in late April around Izu Islands area. Some of the boats operated in the same area together with pole-and-line boats, apparently competing each other. The majority of the catch in this area has been skipjack. 2

Geographical distributions of catches for skipjack, yellowfin and bigeye in the equatorial area are shown in Fig. 17. Annual total catch obtained from the logbook in 2003 in the WCPO by this fishery (Table 4) was 179,000 MT, 27,000 MT and 4,700 MT for skipjack, yellowfin and bigeye, respectively. The skipjack catch was the fourth highest (highest in 1998), and bigeye catch was the third highest (highest in 1997), and the yellowfin catch recovered from the lowest since 1979) but still lower than the recent average. This has resulted from the facts that the skipjack has been abundant in the equatorial waters and the yellowfin free swimming schools were not detected by the fleet for the past two years. Since around 1994, skipjack has been caught in significant amount in the waters around Japan fluctuating between 15,000 and 95,000 MT. In 2003, about 50,000 MT of skipjack, 2,950 MT of yellowfin and 930 MT of bigeye were caught in the vicinity of Japan. Traditionally, this fishery utilized tuna schools in association with natural logs (upper panel of Fig. 18), but since around 1999 FADs have been extensively used when and where natural logs were not available. Natural logs were more often observed in the north of the Equator and free swimming schools were found near the Equator (lower panel of Fig. 18). The correction for the species composition through the port sampling indicates that the bigeye catch in the logbook records was underestimated between 10 and 27 % (Table 5) during the past 7 years. The length frequency distribution for 2003 obtained through the port sampling is shown in Fig. 19. For bigeye and yellowfin the majority of the catch was small fish less than about 70cm in fork length. All three species had a clear mode at about 36-40cm, 50cm and 55-60 cm. Compared to 2002, these locations of mode were somewhat different for all three species. The largest mode of skipjack was 55cm in comparison to 45cm in 2002. This shift of strong cohort has been observed since 2001 that was at about 40 cm in that year. 3. 4. Catch by other coastal fisheries There are several coastal fisheries that catch tropical tunas. Among them the largest catch has been made by the troll fishery operated in the nearshore Japan. Longline and pole-and-line fisheries operated by 20 GRT boats also take significant amount (Table 6). Other coastal fisheries include small scale purse seine, traps, and gillnet whose total catches are very minor. 3.5. Total catch for tropical tunas for all gears combined Trends of total catch for tropical tunas for all gears combined (coastal longline, pole-and-line, troll and other miscellaneous gears) were shown in Table 7 and Fig. 20 for 1972-2002. During this period, bigeye tuna catch has been stable but went down a little since 1993 while the other two (yellowfin and skipjack) species indicated a moderate increase up until the mid 1980s and then declined slightly. The 2002 yellowfin catch was further down and the lowest in this time frame. The 2002 total catch was 36,000 MT, 42,000 MT and 293,000 MT for bigeye, yellowfin and skipjack, respectively. 4. Description of fishing in the western and central Pacific Ocean during 2003 Fishing reports of the Japanese tuna fisheries in the western and central Pacific Ocean in 2003 are briefly summarized below. This information was mainly obtained through the interviews to fishermen at Yaizu fishing port by the NRIFSF staff. 4. 1. Longline fishery The longline fishing grounds are generally formed in three latitudinal bands, where the target and species composition are different depending on the season and mode of operation. These bands are located mostly northern latitudes (25-40N), middle latitudes (15-25N) and equatorial area (10S-15N), extending from 130E to nearly date line. Northern latitudes There are three types of fishing currently being conducted whose target species is different (albacore, bigeye and swordfish, respectively). Albacore is actively fished especially near Japan (around Izu Islands) during winter season (Nov.-March). The other two species (bigeye and swordfish) are targeted all year round, in particular in fall to winter in the high latitudes between 30 and 40 N. The swordfish operations are made at night and often accompanied with considerable catch of blue shark. In 2003, the main albacore fishing was located in waters of 28-38N and 132E-170W. The average catch per day was 0.8-1.5 MT (albacore CPUE=3-6%) and lower than the previous year. Bigeye CPUE was similar to the last year. Albacore, swordfish and striped marlin are also caught in those sets. Middle latitudes The major fishing area are formed both western and eastern sides of Mariana Islands. Majority of catch were large albacore of 6-7 age old with minor catches of bigeye, yellowfin and blue marlin. In general, fishing was a bit better during the first half of the year (average catch was 1.2 MT), but slightly worse (0.7-0.9 MT) during the second half of the year. 3

Equatorial area Fishing grounds in this area are located near Nauru, Marshall Islands and Kiribati where bigeye and yellowfin are the major components. Average catch were between 1.0 and 1.5 MT per set. Bigeye (>25kg) and yellowfin (>15kg) accounted for the most of catch with minor amount of blue marlin. Large albacore (>20kg) was also caught in the northern and southern edge of this area. It was reported that there were many longliners from different nations such as Korea, Taiwan and Mainland China. Johnston Islands The southern waters of Johnston Islands and Hawaii were fished by larger longliners with distant water license. The catch-per-day was 1.2 MT during the first half of 2003 and went down to 0.9 MT in the second half. Major component of the catch was bigeye. Many foreign longliners were often sighted, and it was reported that there were many competitions among boats where to set the gears. Eastern Pacific Ocean (ETP) The fishing was relatively fair (0.7 MT/day) at the beginning of the 2003 and became a bit slow (0.6 MT/day) during the second half of 2003. Average catch-per-day was lower in the western side of ETP. In general, fishing became poorer than 2002. 4.2. Pole-and-line fishery 2003 P&L fishery In 2003 1st quarter, fishing ground of distant water vessels started in the Solomon Island area (12-14S, 160-165 E) and moved to the northern hemisphere of 2-9N, 150-163E. The fishing ground moved north and westward in March and April to the area north of Guam (19-21N, 149-150E). The main fishing ground in May were east of the Truk Island (7-12N, 152-162E) and east of the Mariana Islands (19-25N, 152-160E) and at late May some vessels moved into northern area of 33N, 157E to search albacore. From June to October, vessels operated in the Kuroshio extension area (36-37N, 159-160E) and the Emperor Sea Mount area (35-40N, 167-169E) to catch mainly albacore. Good fishing ground was not formed in September of this season, the majority of catch was consisted of skipjack. Total estimated albacore catch by distant water pole-and-line vessels was about 28,000 MT and decreased to the catch level in 2001. In late November all vessels moved southward and into the fishing ground around the Mariana Islands and Marshal Islands. In December they moved to further south in the Solomon Islands area. Fishing ground for offshore vessels from the January to March in 2003 continued at the Northern Mariana and the Bonin Islands areas (21-28N, 138-146E). Then the fishing ground in April and May were closed to Japanese coast near the Izu Islands of 33-36N, 136-148E. Catch per a vessel-day in 2003 were higher than average value of recent 12 years during March and June. In the beginning of the 2nd half of the year, the skipjack fishing ground for offshore vessels formed near 150E. And then vessels moved to the north and north-westward off the Pacific coast of the northern Japan to 42N in September. This fishing ground disappeared in November. Total estimated landing of offshore vessels in 2003 was at the average level. 2003 skipjack catch in coastal area by coastal pole-and-line fishery (less than 20 GRT) and troll fishery was same level as the average. The quarterly length frequency distribution of pole-and-line caught skipjack in 2003 obtained through the port sampling was shown in Fig. 13. This covers major fishing port for coastal and offshore fisheries and some part of distant water fisheries operating in the Northwestern Pacific (north of 25N). 2nd and 3rd quarters were high season around Japan and majority of catch was composed of 40-50 cm in the 2nd quarter and growing up to 45-55 cm in the 3rd quarter. 2004 P&L fishery Distant water vessels continued operating in the Solomon Islands area in January through March 2004. They moved to the area east of Guam Island of the north equatorial current (7-13N, 150-156E) in April and operated in that area and the area in the subtropical countercurrent near the Mariana Island (18-19N, 150-151E) in May. Then they shifted to further north at the water around the Izu Islands in late May and moved into the Kuroshio extension area west of the Emperor Sea Mount area (35-37N, 160-167E) to catch mainly albacore. Although offshore vessels started their 2004 fishing season at the subtropical countercurrent and moved gradually northward as usual in February, a big albacore fishing ground was formed close to Japan (34N, 139E) in early April and offshore pole and line vessels moved into this area continued to catch albacore together with skipjack through early June. Therefore catch amount of skipjack by offshore vessels in first half of 2004 was less than the average. On the other hand, albacore catch was the highest record catch in recent 23 years. In June and July, the major part of the skipjack school are distributed around 150E where is relatively offshore because of the distribution of the cold eddy from the Oyashio current near the coast of northern Japan. Catches of coastal fisheries such as coastal pole-and-line smaller than 20 GRT and troll were lower than average level throughout of Pacific coast of southern and western Japan in 2004 so far. 4.3. Purse seine fishery 4

2003 fishing is characterized by the significant activities in the waters west of 140E since 1996. This fishing area was fished especially during the second quarter and the east of 160E became the major fishing area during the second half of 2003. Except for the westernmost fishing zone, the general fishing area was similar to the recent years. Skipjack catch became very good since the mid December of 2002 with some catches of large yellowfin around west of Nauru. This has been often observed that the free swimming schools become available to the purse seiners when the North Equatorial Counter Current became weak. In February, this fishing ground has shifted to the south of Nauru and Truk Island, especially in the latter area where log and FADs sets became popular. The area of fishing moved west and was formed between 139-148E in the north of Equator. Free schools and log or FADs sets were targeted in the western part and in the eastern part of this area, respectively. Extraordinary good catch of skipjack was recorded and the price went down to 50-70 yen per kg. This good catch has continued until June moving further west (137-141E). Some boats turned to east in June and operated in 153-155E mainly on log schools. In August some small skipjack were caught, and the fleet shipped to further east and south. Smaller skipjack were mainly caught and high catches were made in October. Yellowfin were also caught in log or FADs sets during December accounting for 25-35% of the total catch in the south of Equator between Nauru and Kiribati. 5. Research activities related to tuna and billfish in the WCPO 6. 1. Bigeye and yellowfin Tropical tuna tagging project in Japan Tagging project on bigeye and yellowfin was started in 1999 in southern Japan, and is being continued. Major objectives of this project are to provide movements of fish in this area in relation to the surrounding waters, detailed movements around the anchored FADs, information on growth, the degree of exploitation by fishing gear in the area and so on. To date, nearly 1350 bigeye and 5160 yellowfin of 30-65cm in fork length were released, of which 185 bigeye and 530 yellowfin were recaptured. At the same time, archival tagging was also conducted for both species. Although the days at liberty of most recaptures are short, interesting results on the swimming behavior of these species are being gathered. More detail information is given in Matsumoto et al, (2003). Pop-up satellite tagging for medium-sized bigeye (110-130 cm) has begun last year and three fishes were already released in the eastern offshore of Japan in June (33-37N, 151-152E) from a commercial longliner. So far no bigeye was released primarily due to the bad fishing in this area. Three pop-up tags will be deployed in the central Pacific from the research longline boat. Verification of otolith daily ring by Oxytetracycline (OTC) injection In order to verify the daily rings on otolith of bigeye and yellowfin tunas, four experiments to rear tunas in captivity were conducted in 2000-2002. In 2002, alizarin complexion was used in addition to OTC. As the number of bigeye used for the past experiments was not enough, the experiment is now being repeated only for bigeye. Total of 72 bigeye, whose fork length was 43 to 58 cm, have been kept in a pen after OTC was injected. Of those, 70 % fish were injected twice. These fishes will be retrieved at the end of July and used to verify the daily rings. Study on the swimming behavior of small tunas around the FADs in open ocean In 2001, a research cruise was conducted by the R/V Shoyo maru in the central Pacific. Small tunas were released around the FADs after they were attached with ultrasonic tags. More than 20 individuals were monitored simultaneously and tracked. The results indicated that smaller fish tended to swim shallower layer than the larger ones. To reinforce this result and obtain more observations, another research cruise was conducted in the EEZ of Solomon Islands and further east during the late October to early November in 2003. Although the number of fish monitored was fewer but it confirmed that bigeye tended to swim slightly deeper waters than yellowfin but they often swam the similar depth range. It was also indicated the lower depth of the swimming range appeared to be restricted by the water temperature (21 C). Taking into consideration of results of these experiments, it seems difficult to selectively avoid catching bigeye tuna by adjusting the depth of net in tuna purse seining. Stock assessment with Multifan-CL model Collaborative study has been continued among the scientists from SPC, IATTC, US, Japan and others. This year Japan sent scientists to SPC before this SCTB in order to provide an improved abundance indices as well as the most recent stock assessment on Pacific tuna stocks. Improvement of input data, i.e., data processing of the catch and effort as well as size data for the earlier part of the fishery has been mostly completed, and they were used in the current stock assessment. 6. 2. Skipjack Skipjack tagging Three research and two training pole and line vessels were involved in the skipjack tagging. In addition, one commercial distant water purse seiner conducted voluntarily tagging throughout of her operations in the temperate water. Total of 2,597 skipjack and one albacore were released in 2003 and 240 skipjack were recovered so far. Of 5

these, 198 skipjack were released from the distant water purse seiner and 5 fish were recovered. Tag and releases in the 1st quarter of the year were distributed in the area south of 25N. In 2nd and 3rd quarters, the North western Pacific off Japan was the main area for tagging. Some releases were conducted near Japan in 4th quarter also and there were releasing in the tropical waters in this period, too. Works on skipjack otolith Based on the otolith increments reading method validated (Tanabe et al, 2003a and 2003b), age and growth study was continued for skipjack in the EPO and Indian Ocean as well as the WCPO (Kayama et al., 2004). In order to examine the WCPO skipjack migration pattern in their life history, the strontium (Sr) and calcium (Ca) concentrations in the otoliths were measured (Arai et al., 2004). Sr:Ca ratios of the skipjack otloiths could be used as an environmental indicator to detect the water temperature experienced in their migratory history. 6. 3. Swordfish and billfishes NRIFSF conducts some biological studies on billfishes caught in the northwest Pacific. This year s outline is summarized as follows; Size data sampling. Unsexed size data of billfishes caught mainly in the northwest Pacific are collected in major ports of Japan. In 2002, numbers of data for swordfish was about 36,000, and 7,200 for striped marlin and 20 for blue marlin. In addition, sexed size data of swordfish caught by Japanese surface longliners operating in the northwest Pacific, and sexed sized data of blue marlin caught by small trolling boat operating in southwestern part of Ryukyu Islands. Number of sexed size data of swordfish in 2003 was about 8,000, and blue marlin was about 2,000. Tagging study NRIFSF is conducting traditional tagging activities on billfishes in cooperation with longline and sports fishermen. In addition, 5 archival pop-up tags were attached on blue marlin caught by a coastal trolling boat in 2003. Two tags were attached in southwestern part of Ryukyu Islands in May, and 3 were attached in the eastern coastal area of Honshu. In 2004, one archival pop-up tag was attached on blue marlin in near shore area of Guam Island and 2 were attached in the southwestern part of Ryukyu Islands. Among these eight pop-up tags applied, archived data of 7 tags were obtained. Total amount of collected data was about 180 days. Cooperative traditional tagging program on marlins between NRIFSF and Japan Game Fish Association has commenced in the spring of 2004. Biological study Stomach contents analysis is being conducted for swordfish caught by the Japanese offshore longliners, and for blue marlin caught by the coastal trolling boats. Aging study for blue marlin caught in near shore Japan is also commenced in collaboration with a university. References MAFFJ 1954-2003. Annual report of catch statistics on fishery and aquaculture, 1953-2002. Statistical and Survey Division, Ministry of Agriculture and Forestry. Arai, T., A. Kotake, S. Kayama, M. Ogura, and Y. Watanabe. (2004): Movements and stock discrimination of skipjack tuna, Katsuwonus pelamis, in the western Pacific by otolith Sr:Ca ratios. SCTB17 Kayama, S, T. Tanabe, M. Ogura, H. Okamoto, and Y. Watanabe (2004): Daily age of skipjack tuna, Katsuwonus pelamis (Linnaeus), in the eastern Indian Ocean. IOTC-2004-WPTT-03. 6p. Matsumoto, T., Okuhara, M., Ohta, I., Mizoguchi, M. and Miyabe, N. (2003): Report of the ongoing tagging project on tropical tunas around Japan. SCTB16/RG-4. 12 pp. Tanabe T, Kayama S, Ogura M. Tanaka S. (2003a): Daily increment formation in otoliths of juvenile skipjack tuna Katsuwonus pelamis. Fisheries Sci. 69: 731-737. Tanabe T, S. Kayama, and M. Ogura (2003b): Precise age determination of young to adult skipjack tuna (Katsuwonus pelamis) with validation of otolith daily increment. SCTB16 SKJ-8. 10p 6

Table 1. Number of fishing vessels engaged in tuna fisheries in the Pacific Ocean by type of fishery and size of vessel. Year/ Size class 1-19 GRT 20-49 GRT Longline fishery *1 50-99 GRT 100-199 GRT 200- GRT Total 1-19 20-49 GRT *2 GRT Pole-and-line fishery 50-99 GRT 100-199 GRT 50-200- GRT Total 199 GRT Purse seine fishery 1953 669 322 430 264 48 1733 4101 148 296 178 4723 1954 743 401 516 304 98 2062 4814 180 303 227 4 5528 1955 588 374 567 371 142 2042 4646 162 260 279 14 5361 1956 595 330 618 371 176 2090 4079 146 238 285 18 4766 1957 443 247 653 365 210 1918 4560 101 225 277 18 5181 1958 366 318 641 351 239 1915 5013 87 239 273 24 5636 1959 541 365 687 330 259 2182 3870 98 234 262 26 4490 1960 843 568 671 298 305 2685 4705 109 179 229 28 5250 1961 694 685 606 238 406 2629 5046 141 132 178 26 5523 1962 660 655 553 158 477 2503 4009 186 111 126 28 4460 1963 774 663 531 199 508 2675 6041 240 111 112 29 6533 1964 610 701 399 208 485 2403 3829 291 103 106 32 4361 1965 696 680 352 208 456 2392 3654 298 91 148 35 4226 1966 147 697 324 214 495 1877 3620 299 71 167 34 4191 1967 147 704 301 226 531 1909 3550 296 54 173 41 4114 1968 231 655 319 228 558 1991 2670 276 60 170 55 3231 1969 895 532 327 232 572 2558 3475 248 71 156 53 4003 64 4 68 1970 890 384 381 183 605 2443 3148 220 91 140 61 3660 62 6 68 1971 908 340 402 164 656 2470 3168 165 133 129 83 3678 62 6 68 1972 940 237 418 148 628 2371 3596 131 162 116 145 4150 65 7 72 1973 959 165 510 120 633 2387 2998 93 210 80 199 3580 56 6 62 1974 518 128 578 110 700 2034 3225 136 269 84 227 3941 52 10 62 1975 720 106 577 88 647 2138 2648 95 283 39 279 3344 52 12 64 1976 827 97 597 77 625 2223 3101 51 318 17 267 3754 53 15 68 1977 726 86 658 72 612 2154 3348 40 348 14 260 4010 50 14 64 1978 669 87 707 69 617 2149 3035 26 358 10 251 3680 47 14 61 1979 648 69 720 82 624 2143 3480 14 370 13 228 4105 46 17 63 1980 821 57 715 103 645 2341 3232 14 350 10 198 3804 50 16 66 1981 774 55 706 100 661 2296 3064 10 353 6 179 3612 50 23 73 1982 722 43 634 90 589 2078 3011 11 320 6 138 3486 52 33 85 1983 561 38 589 93 550 1831 3021 12 297 9 116 3455 59 36 95 1984 523 32 538 108 610 1811 2904 8 273 10 105 3300 54 33 87 1985 620 28 512 131 628 1919 2754 8 244 9 95 3110 47 35 82 1986 536 25 435 168 632 1796 2455 6 224 9 91 2785 53 38 91 1987 661 23 348 197 649 1878 2404 6 210 9 89 2718 47 34 81 1988 586 21 289 233 649 1778 2613 5 191 11 70 2890 48 39 87 1989 650 20 248 238 653 1809 2254 3 187 12 67 2523 43 37 80 1990 685 21 227 241 664 1838 2228 4 176 9 66 2483 43 35 78 1991 768 19 199 222 682 1890 2277 3 166 10 63 2519 38 35 73 1992 793 19 164 206 681 1863 2093 3 156 11 46 2309 31 38 69 1993 790 18 138 201 682 1829 1927 3 147 10 43 2130 27 36 63 1994 819 21 110 198 675 1823 1830 3 124 10 48 2015 23 33 56 1995 738 20 92 187 667 1704 481 3 104 20 46 654 20 31 51 1996 711 17 91 155 640 1614 512 3 89 29 43 676 21 32 53 1997 698 11 88 145 631 1573 436 2 76 39 45 598 20 35 55 1998 712 11 80 129 623 1555 382 2 73 40 46 543 20 35 55 1999 703 6 78 119 567 1473 416 1 62 54 46 579 22 36 58 2000 732 3 76 111 496 1418 357 1 56 57 47 518 23 37 60 2001 777 4 76 110 494 1461 285 1 51 57 47 441 19 36 55 2002 780 4 69 110 479 1442 251 1 45 58 48 403 18 35 53 2003 (18) (35) (53) *1 Boats larger than 50 GRT include those operated in the area other than the Pacific. *2 Number of 1-19 GRT class boat for 1966-1968 does not includes boats less than 10 GRT, and boats before 1995 include those boats engaged in trolling. *3 Figures in the parentheses indicate provisional data. 200- GRT Total 7

Table 2. Fishing effort (in million hooks) and catch (number in thousands and weight in MT) in the WCPO by species for the Japanese longline fishery (boats larger than 20 GRT). FAO s species codes are used to express species name. Number of fish Weight Year Hooks ALB BET YFT SWO MLS BUM BAM SAI SSF ALB BET YFT SWO MLS BUM BAM SAI SSF Total 1970 206 1084 701 1186 119 171 136 16 42 18,431 28,959 34,908 6,213 6,135 8,225 1,233 895 104,999 1971 216 805 729 1090 134 124 77 19 33 13,030 30,126 29,974 7,131 4,816 4,709 1,271 771 91,828 1972 207 736 979 1057 123 86 100 14 32 12,101 39,658 29,677 6,555 3,455 6,177 980 774 99,377 1973 189 795 693 1173 110 97 88 13 46 13,161 28,231 30,906 5,792 3,766 5,106 904 1,128 88,994 1974 210 646 795 1194 122 91 90 12 34 11,467 32,132 33,899 6,339 3,475 5,193 824 806 94,135 1975 183 427 796 1047 132 59 60 9 22 7,622 32,148 28,921 6,682 2,233 3,409 657 496 82,168 1976 220 766 889 1130 152 56 62 6 26 12,738 38,786 32,521 7,859 2,112 3,707 413 628 98,764 1977 199 649 1026 1564 139 37 68 7 19 10,782 41,843 43,950 7,752 1,505 4,206 552 449 111,039 1978 205 574 926 2254 147 48 80 11 15 9,636 35,456 62,622 7,937 2,033 5,045 814 370 123,913 1979 240 670 972 1794 164 88 70 10 18 10,799 37,173 50,879 8,803 3,574 4,500 763 454 116,945 1980 259 705 939 2314 133 86 94 10 24 11,821 35,599 63,289 6,573 3,393 6,071 758 609 128,113 1981 273 1059 756 1930 155 69 83 10 23 17,025 28,390 53,594 7,956 3,081 5,382 707 608 116,743 1982 243 1014 872 1617 133 62 81 9 17 16,273 32,714 46,205 6,894 3,093 5,440 689 478 111,786 1983 214 860 815 1629 152 45 64 7 11 13,335 28,998 47,526 7,942 2,094 4,238 568 279 104,980 1984 216 720 889 1254 147 63 93 7 12 11,216 31,508 36,669 7,583 2,787 6,006 561 317 96,647 1985 223 764 947 1328 196 88 80 7 8 11,688 33,348 38,278 10,223 3,653 5,185 537 213 103,125 1986 196 676 752 996 181 115 85 4 9 10,493 29,825 29,968 9,414 4,397 5,422 306 230 90,055 1987 202 662 942 901 184 70 61 4 9 10,516 38,429 28,045 9,493 2,809 3,806 317 231 93,646 1988 222 795 769 1077 182 127 78 6 14 12,166 29,331 33,021 9,641 4,763 4,934 556 311 94,723 1989 200 748 827 860 135 89 61 2 12 11,273 32,189 25,639 6,897 3,836 3,936 215 272 84,257 1990 192 820 933 890 126 55 46 2 9 12,045 37,117 26,862 6,404 2,334 2,843 138 219 87,962 1991 170 694 680 635 102 67 46 2 7 10,985 25,507 19,221 5,315 2,532 2,834 129 170 66,693 1992 154 816 708 716 111 54 36 2 7 12,494 30,852 24,067 8,821 2,331 2,558 149 220 81,492 1993 164 1172 625 746 120 83 53 2 9 17,376 25,795 24,052 9,194 3,228 3,446 181 184 83,456 1994 158 1130 612 734 111 73 51 3 5 10 17,239 23,090 24,451 8,319 2,937 3,499 242 137 122 80,036 1995 141 1006 524 865 85 79 50 2 4 9 15,522 19,747 25,189 6,974 3,058 3,370 152 95 95 74,202 1996 127 1004 487 778 93 54 30 1 1 4 15,794 16,565 20,422 7,470 2,078 1,934 89 14 36 64,402 1997 121 1038 638 584 88 43 29 1 1 3 16,495 21,471 17,370 7,616 1,668 1,800 71 25 35 66,551 1998 121 1046 673 454 75 53 32 1 3 5 15,770 25,549 14,960 6,730 2,169 1,944 97 60 94 67,373 1999 121 754 527 351 67 41 34 1 1 5 12,476 21,911 11,120 5,895 1,444 2,129 50 19 83 55,126 2000 121 693 443 562 76 25 33 1 1 4 12,411 19,187 18,716 5,986 962 1,981 64 25 77 59,408 2001 118 901 482 341 68 28 30 0 2 3 14,179 20,219 11,239 5,769 1,034 1,712 33 39 48 54,273 2002 126 692 627 410 74 19 30 1 4 2 10,429 24,488 12,297 6,375 698 1,703 81 66 37 56,175 2003 126 532 545 454 63 33 32 0 4 4 7,258 20,573 12,501 5,466 1,332 1,908 41 63 78 49,220 8

Table 3. Days fished, number of poles used, and catch (MT) by species for the Japanese pole-and-line fishery (larger than 20GRT) in the WCPO. Number of Number of Catch in MT Year fishing days poles Skipjack Yellowfin Bigeye Albacore Others Total 1972 46,657 1,099,823 140,976 5,544 1,627 48,578 2,801 199,526 1973 55,750 1,226,485 209,285 6,057 1,149 61,168 2,321 279,980 1974 55,740 1,201,499 219,455 4,407 970 68,828 2,727 296,387 1975 58,920 1,168,888 181,093 5,420 1,281 47,660 2,155 237,609 1976 65,090 1,270,406 221,015 7,351 3,313 78,451 3,662 313,792 1977 75,988 1,540,551 245,406 9,906 3,231 34,953 1,935 295,431 1978 66,793 1,375,200 238,267 7,633 3,183 56,658 1,976 307,717 1979 66,418 1,277,649 211,911 5,836 2,140 44,982 2,387 267,256 1980 64,432 1,185,192 236,542 6,191 1,994 43,020 3,089 290,837 1981 64,430 1,211,871 200,719 9,054 2,338 25,599 3,659 241,369 1982 60,853 1,084,286 200,154 9,499 3,810 28,822 3,946 246,230 1983 51,019 914,316 224,530 9,338 3,772 19,596 3,656 260,893 1984 50,426 875,363 284,495 8,702 3,211 25,920 2,209 324,537 1985 43,619 788,122 159,175 12,925 3,981 21,039 3,347 200,467 1986 41,187 725,687 233,723 8,410 2,519 13,820 2,130 260,602 1987 39,391 692,615 177,518 8,454 2,816 19,054 2,970 210,811 1988 33,088 582,187 201,004 8,129 3,660 7,130 2,381 222,304 1989 34,564 561,139 184,137 9,146 3,570 10,919 2,486 210,257 1990 34,303 517,185 122,391 6,970 3,331 13,820 3,945 150,458 1991 23,542 343,199 151,338 5,404 1,232 6,469 2,269 166,711 1992 24,264 358,785 118,649 6,904 1,028 14,856 3,416 144,853 1993 24,375 376,858 162,403 4,529 1,770 12,471 1,111 182,284 1994 21,697 347,612 108,944 4,035 1,908 30,278 811 145,975 1995 22,140 356,335 132,620 4,527 2,627 22,828 1,626 164,228 1996 20,944 341,328 97,916 4,883 2,549 22,365 588 128,300 1997 22,411 374,011 122,500 3,727 2,584 34,849 880 164,539 1998 22,350 379,873 124,191 3,062 1,352 27,689 1,859 158,153 1999 22,905 409,636 122,290 3,646 1,097 54,956 673 182,662 2000 23,593 428,140 138,860 3,475 1,792 21,502 383 166,011 2001 22,050 405,319 96,144 2,616 1,321 29,225 1,191 130,496 2002 20,960 390,937 90,466 2,501 1,714 49,443 514 144,637 9

Table 4. Days fished and catch (MT) by species for the Japanese tuna purse seine fishery (larger than 100 GRT) in the WCPO based on logbook data. Others include other tuna and tuna-like species. Year Days fished SKJ YFT BET Others Total 1970 141 415 223 0 0 637 1971 2,028 8,221 3,355 128 4,423 16,127 1972 2,561 12,311 5,718 136 2,515 20,679 1973 2,723 13,616 7,735 182 2,245 23,778 1974 1,998 5,886 9,724 372 1,860 17,841 1975 2,265 7,275 5,777 267 4,766 18,085 1976 2,529 17,741 7,651 390 2,747 28,528 1977 2,232 18,498 6,807 302 6,100 31,707 1978 2,429 25,821 8,523 609 10,013 44,967 1979 3,622 28,760 19,023 720 12,870 61,372 1980 3,716 48,820 20,077 564 12,206 81,667 1981 4,736 44,773 27,539 925 25,005 98,243 1982 6,103 75,152 31,098 1,131 17,276 124,657 1983 8,560 117,038 30,830 1,468 14,827 164,163 1984 9,657 128,975 38,662 702 7,448 175,787 1985 9,741 119,204 47,941 1,381 7,716 176,241 1986 8,985 130,900 44,467 1,531 8,709 185,606 1987 9,075 115,455 44,634 1,602 11,569 173,259 1988 9,143 183,673 30,125 606 5,006 219,409 1989 9,188 122,041 40,872 1,528 8,221 172,662 1990 8,321 140,134 37,757 2,122 6,065 186,078 1991 7,818 150,156 48,598 1,951 8,241 208,945 1992 7,404 140,177 53,099 2,563 8,883 204,721 1993 8,451 136,889 57,858 1,903 5,038 201,688 1994 7,851 160,151 39,866 1,676 10,004 211,697 1995 8,755 143,179 45,183 1,629 14,413 204,403 1996 9,362 156,177 24,539 1,494 6,293 188,503 1997 9,031 156,904 57,475 8,467 12,674 235,519 1998 8,046 230,247 37,712 2,706 4,126 274,791 1999 9,368 150,321 43,847 3,523 20,242 217,934 2000 9,415 171,638 36,590 4,779 19,571 232,578 2001 8,027 169,380 33,737 6,131 10,164 219,411 2002 8,311 188,052 19,138 4,587 13,169 224,945 2003 8,383 179,375 26,592 4,689 7,370 218,026 * Based on logbook data. Table 5. Comparison of species composition between landing and corrected statistics through the port sampling for the Japanese purse seine fishery (equatorial fishery), 1996-2003 (unit=mt). Landing Estimated by port sampling Year SKJ YFT BET Total SKJ YFT BET Total 1996 137,047 26,889 1,947 165,883 137,278 25,424 2,665 165,367 1997 84,805 49,665 11,638 146,109 84,732 49,745 13,082 147,559 1998 132,378 37,723 4,217 174,318 129,693 35,793 4,813 170,299 1999 116,017 43,304 4,882 164,203 115,600 42,520 5,667 163,787 2000 139,087 37,960 6,336 183,382 138,553 35,438 8,660 182,651 2001 113,030 43,074 8,657 164,761 113,004 42,080 9,567 164,652 2002 148,287 22,585 4,497 175,370 148,287 21,297 5,784 175,368 2003 125,834 29,955 3,822 159,610 10

Table 6. Catch statistics of major tuna species for coastal and other miscellaneous gears. All these gears were operated by the small boats less than 20 GRT. More than 90 % of the catch by other fisheries has been made by troll fishery. Year Coastal LL Coastal PL Bigeye Yellowfin Skipjack Other PS Other fisheries Total Coastal LL Coastal PL 1970 565 10 85 64 724 4,220 116 3,347 1,287 8,970 32 6,237 4,321 6,670 17,260 1971 559 47 30 24 660 3,057 188 1,536 227 5,008 18 5,041 768 2,301 8,128 1972 732 135 1 20 888 3,794 258 841 839 5,732 25 10,935 653 6,243 17,856 1973 913 109 4 58 1,084 2,576 234 1,575 430 4,815 39 7,902 565 10,243 18,749 1974 1,091 69 25 99 1,284 2,477 253 797 690 4,217 25 12,864 575 6,112 19,576 1975 2,167 53 5 200 2,425 5,237 285 66 572 6,160 13 8,506 252 5,646 14,417 1976 2,833 59 18 256 3,166 7,132 213 944 871 9,160 64 10,070 572 7,047 17,753 1977 2,512 35 10 198 2,755 7,605 104 74 536 8,319 60 12,099 381 7,146 19,686 1978 2,883 38 12 544 3,477 7,873 149 522 615 9,159 36 17,673 880 10,296 28,885 1979 3,376 88 47 347 3,858 6,867 224 684 1,420 9,195 16 11,896 236 8,198 20,346 1980 2,658 22 0 113 2,793 5,840 111 878 842 7,671 17 13,538 721 8,472 22,748 1981 2,523 56 1 152 2,732 5,123 147 46 733 6,049 15 10,556 906 7,599 19,076 1982 2,904 109 0 172 3,185 5,117 301 420 528 6,366 4 12,841 398 11,590 24,833 1983 4,201 93 0 134 4,428 6,207 191 5 497 6,900 1,134 12,801 244 12,301 26,480 1984 5,168 26 5 137 5,336 5,968 347 149 776 7,240 13 11,835 196 13,912 25,956 1985 4,607 111 10 228 4,956 6,229 502 119 653 7,503 54 9,520 144 7,478 17,196 1986 4,475 118 5 258 4,856 6,199 326 28 676 7,229 36 13,090 388 15,863 29,377 1987 4,023 86 0 173 4,282 7,148 317 130 963 8,558 30 8,425 114 12,469 21,038 1988 5,012 221 0 260 5,493 7,528 502 2 1,346 9,378 46 11,505 45 18,393 29,989 1989 6,101 373 0 379 6,853 7,685 472 5 1,399 9,561 42 8,928 59 14,300 23,329 1990 7,053 144 0 104 7,301 7,800 211 0 694 8,705 57 7,357 66 18,217 25,697 1991 7,025 130 5 354 7,514 8,034 182 0 1,293 9,509 82 6,448 221 19,757 26,508 1992 7,302 75 0 593 7,970 8,452 209 12 1,548 10,221 79 7,554 121 15,040 22,794 1993 6,889 31 0 137 7,057 7,950 157 3 1,706 9,816 157 9,818 139 10,886 21,000 1994 5,974 323 0 173 6,470 6,970 259 0 1,476 8,705 81 7,537 65 6,999 14,682 1995 5,532 397 0 206 6,135 6,886 503 28 1,550 8,967 111 5,929 160 13,909 20,109 1996 6,067 428 0 308 6,803 6,257 384 1 1,616 8,258 70 5,811 19 7,369 13,269 1997 5,442 288 2 372 6,104 6,079 492 8 2,083 8,662 103 6,364 11 9,951 16,429 1998 4,846 180 0 282 5,308 5,888 477 68 2,043 8,476 67 6,845 100 9,718 16,730 1999 5,805 134 0 240 6,179 5,500 515 3 4,974 10,992 74 6,805 88 7,391 14,358 2000 6,042 125 0 204 6,371 6,895 377 6 2,421 9,699 98 8,926 41 16,528 25,593 2001 5,587 56 0 211 5,854 5,944 520 2 3,136 9,602 56 7,288 333 8,810 16,487 2002 4,942 43 2 161 5,148 4,434 874 87 2,841 8,236 30 6,901 222 7,756 14,909 Other PS Other fisheries Total Coastal LL Coastal PL Other PS Other fisheries Total 11

Table 7. Japanese total catches (all gears combined) for tropical tuna species. Year BET YFT SKJ Total 1972 42,292 45,147 171,140 258,579 1973 30,646 49,054 241,322 321,022 1974 34,714 51,941 244,706 331,362 1975 36,119 46,045 202,356 284,520 1976 45,655 56,681 256,593 358,928 1977 48,131 69,016 283,756 400,904 1978 42,724 87,938 293,016 423,678 1979 43,891 84,933 261,045 389,868 1980 40,950 97,228 308,149 446,327 1981 34,385 96,236 264,597 395,218 1982 40,838 93,158 300,156 434,152 1983 38,666 94,595 368,084 501,345 1984 40,758 91,273 439,479 571,509 1985 43,666 106,653 295,719 446,037 1986 38,731 90,073 394,083 522,887 1987 47,128 89,691 314,076 450,895 1988 39,090 80,647 414,598 534,334 1989 44,140 85,218 329,524 458,882 1990 49,872 80,279 288,223 418,373 1991 36,204 82,713 327,868 446,784 1992 42,413 94,280 281,647 418,341 1993 36,524 96,288 320,659 453,470 1994 33,144 77,056 283,860 394,060 1995 30,139 83,866 296,041 410,046 1996 27,411 58,101 267,406 352,918 1997 38,626 87,234 295,870 421,730 1998 34,904 64,140 370,565 469,609 1999 32,388 68,622 268,858 369,867 2000 32,130 68,479 336,105 436,714 2001 33,525 57,190 282,077 372,792 2002 35,937 42,171 293,463 371,571 Table 8. Number of fish released and recaptured in the tropical tuna tagging project conducted in the Nansei Islands area (Okinawa and Amami Islands). Dart tag Species Bigeye tuna Yellowfin tuna Total Year Rel. Recap. % recap. Rel. Recap. % recap. Rel. Recap. % recap. 2000 442 99 22.4% 1174 166 14.1% 1616 265 16.4% 2001 374 37 9.9% 1435 90 6.3% 1809 127 7.0% 2002 170 15 8.8% 970 55 5.7% 1140 70 6.1% 2003 365 34 9.3% 1580 219 13.9% 1945 253 13.0% Total 1351 185 13.7% 5159 530 10.3% 6510 715 11.0% Archival tag Species Bigeye tuna Yellowfin tuna Total Year Rel. Recap. % recap. Rel. Recap. % recap. Rel. Recap. % recap. 2000 20 6 30.0% 13 1 7.7% 33 7 21.2% 2001 16 1 6.3% 24 2 8.3% 40 3 7.5% 2002 19 6 31.6% 10 1 10.0% 29 7 24.1% 2003 7 0 0.0% 19 1 5.3% 26 1 3.8% Total 62 13 21.0% 66 5 7.6% 128 18 14.1% 12

Longline Boats by Size Class (GRT) Pole-and-Line Boat by Size Class (GRT) Fig. 1. Trend of fleet size for longline and pole-and-line boats by size (GRT), 1953-2002. 13

100 90 80 70 Longline fishing effort by area 250 200 140,000 120,000 100,000 Catch by Species Hooks 60 50 40 30 150 100 Total Hooks Catch (MT) 80,000 60,000 40,000 20 50 20,000 10 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03 0 1971 1976 1981 1986 1991 1996 2001 Year Japan Japan East Year Hawaii North Total Total ALB BET YFT Hooks 100 90 80 70 60 50 40 30 20 10 Longline fishing effort by area 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99 01 03 Equatorial west Year Solomon Johnston South Fig. 2. Trend of fishing effort (hooks) for the Japanese offshore and distant water longline fisheries by area. Area definition is as follows : Japan : 20-45N, 130-165E, Japan East : 20-45N, 165E-175W, Hawaii North : 20-45N, 175-150W, Equatorial West : 15S-20N, 130-165E, Solomon : 15S-20N, 165E-175W, Johnston : 15S-20N, 175-150W, South : 40S-15S, 145E-150W. Catch (MT) 20,000 18,000 16,000 14,000 12,000 10,000 8,000 6,000 4,000 2,000 0 Catch by Species 1971 1976 1981 1986 1991 1996 2001 Year SWO MLS BUM Total 140,000 120,000 100,000 80,000 60,000 40,000 20,000 Fig. 3. Trend of catches (MT) for the Japanese offshore and distant longline fishery by major species. 0 Total (MT) 14

Fig. 4. Past distribution of fishing effort for the Japanese offshore and distant water longline fisheries in the western and central Pacific Ocean, 1960, 1970, 1980 and 2002. Fig. 5. Quarterly distribution of fishing effort for the Japanese offshore and distant water longline fisheries in the western and central Pacific Ocean in 2002. 15

Fig.6. Distributions of offshore and distant water longline catch (weight) by species in 2001-2002 for five main species (ALB:albacore, BET:bigeye tuna, YFT: yellowfin tuna, SWO: swordfish and BUM: blue marlin). SWO 11% MLS 1% BUM 3% ALB 19% SWO 18% MLS 1% BUM 3% ALB 20% YFT 22% BET 44% YFT 22% BET 36% Fig.7. Overall catch composition for offshore and distant water longline fisheries (left) and coastal longline fishery (right) in 2002. (ALB:albacore, BET:bigeye tuna, YFT: yellowfin tuna, SWO: swordfish, MLS: striped marlin and BUM: blue marlin) 16

Fig. 8. Distribution of fishing effort for the Japanese small scale longliners (less than 20 GRT) in the western Pacific Ocean. Data are aggregated for 2000 to 2002. Fig.9. Distributions of catch (weight) by species for small scale longliners in 2001-2002 for five main species (ALB:albacore, BET:bigeye tuna, YFT: yellowfin tuna, SWO: swordfish and BUM: blue marlin). 17

Fig. 10. Trends of fishing effort and catches by species for the Japanese pole-and-line fishery (>20GRT) in the WCPO. 18

Fig. 11. Annual distribution of fishing effort for the Japanese pole-and-line fishery (offshore and distant water licenses) in the Pacific Ocean in 1975, 1985, 1995, and 2001. Fig. 12. Quarterly distribution of fishing effort for the Japanese pole-and-line fishery (offshore and distant water licenses) in the Pacific Ocean in 2002. 19

3,000 2,000 1,000 0 3,000 2,000 1,000 0 3,000 2,000 1,000 0 3,000 2,000 1,000 0 Fig.13. Distribution of pole-and-line catch in 2002 for skipjack (top) and yellowfin tune (bottom). Fig. 14. Quarterly length frequency distribution in 2003 for pole-and-line (coastal, offshore, and distant water) caught skipjack in the northwestern Pacific, north of 25N. 20

Fig. 15. Trends of fishing effort and catches by species for the Japanese tuna purse seine fishery in the WCPO. 21

Fig. 16. Annual (top) and quarterly distributions (lower four panels) of fishing effort for the Japanese tuna purse seine fishery (larger than 100 GRT) in the Pacific Ocean in 2003. 22

Fig. 17. Distribution of purse seine catch (MT) by species (lower panel) combined for 2001-2003. Set type was classified as free swimming, natural log and FADs schools. 800 700 Number of Sets 600 500 400 300 200 100 Free Log FADs 0 93 1 7 94 1 7 95 1 7 96 1 7 97 1 7 98 1 7 99 1 7 00 1 7 01 1 Monthly sets by type of school 7 02 1 7 03 1 7 Fig. 18. Trend of monthly number of sets by type of association and sets by type of school since 1993 (upper) and distribution of sets by type of school for 2001-2003 deployed by the equatorial tuna purse seine fishery by Japan. 23