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ISC/13/ALBWG/13 Preliminarily analysis for target species of Japanese longline fishery operated in the North Pacific Ocean Keisuke Satoh, Hirotaka Ijima, Hidetada Kiyofuji and Hiroaki Okamoto National Research Institute of Far Sea Seas Fisheries Fisheries Research Agency 5-7-1 Orido, Shimizu-ku, Shizuoka-shi 424-8633 Japan Email: [email protected] 1 This working paper was submitted to the ISC Albacore Working Group Intercessional Workshop, 19-26 March 2013, held at the College of Marine Sciences, Shanghai Ocean University, Shanghai, China. Document not to be cited without author’s permission. Preliminarily analysis for target species of Japanese longline fishery operated in the North Pacific Ocean Keisuke Satoh1, Hirotaka Ijima1, Hidetada Kiyofuji1 and Hiroaki Okamoto1 1 National Research Institute of Far Seas Fisheries, 5-7-1 Shimizu-ku, Shizuoka 424-8633, Japan. SUMMALY In order to understand the target species of Japanese longline fishery in the Pacific Ocean from 1993 to 2002, we investigated historical changes of (1) species composition (albacore, bigeye and yellowfin) of the fishery, (2) distribution of number of fish per set using operational logbook data and (3) market price in Japanese fishing ports, and amount of import. Four pieces of evidence revealed the operation of targeting albacore of Japanese longline fishery in the North Pacific Ocean increased in this period from 1993 to 2002. First, the historical trend for species composition represented the proportion for albacore was high and the proportion for bigeye was low in this period. Second, elongation of fishing season for albacore of the large vessel occurred for the large vessel, which had been often observed before 1970 when the fishery mainly targeted albacore. Third, the proportion of zero catch and more than 100 fish per set for albacore of the large vessel was lower and very high, respectively. Such high proportion was also observed before 1970. The last one, the total quantity demanded for albacore and bigeye increased and decreased, respectively. 1. INTRODUCTION Standardized CPUE for albacore caught by Japanese longline fishery in the North Pacific Ocean increased and decreased in 1990s (from 1992 to 2002), and the stock assessment model cannot explain this trend. Therefore further exploration of Japanese longline CPUE was recommended in the last stock assessment (Anonymous ISC 2011). To address the point, we focus on historical changes of target species of the fishery. If albacore had been targeted in 1990s by Japanese longline, nominal CPUE could be high and then the standardized CPUE might be biased without consideration for targeting effect. Japanese fishermen of longline with large vessel (larger than 20 gross register tonnages (GRT)) had generally targeted albacore until early 1970s, and then they changed their target species as bigeye in tandem with the penetration of deep setting and nylon for material of main and branch line. After that the main target species was not seen as not having largely changed. However consistent increasing of albacore catch by Japanese longline fishery since 1990 in the Indian Ocean (Matsumoto 2012) and increasing trend with some fluctuation since 1995 in the Atlantic Ocean (Anonymous ICCAT 2012a) indicate changing of target species of the fishery after 1990s. 2 For small vessel (10-19 GRT), it is difficult to descript historical target species before 1993 due to lack of logbook. However we try to review typical fishing schedule and target species. Application of deep setting and nylon for line material seems to have smaller impact on changing target species rather than large vessel. The small vessels have changed target species seasonally and opportunistically as albacore, yellowfin, bigeye and bluefin. They target albacore in 1st quarter and then move to bluefin, and stop fishing from June to August. They resume fishing in September to catch bigeye in eastern area of the North Pacific Ocean (35 to 40 N, from coast line of Japan to 160 E). The fishing season for bigeye continue to December or early January. They also catch yellowfin in coastal area from late spring to summer. There should be many exemptions for the typical schedule. For example, some vessels go to tropical area year-round and catch tropical tuna, and smaller sized vessels tend to operate in coastal area and target albacore, and some vessels catch albacore in southern part of the eastern area in 4th quarter in recent years. In order to understand the target species of Japanese longline fishery in the Pacific Ocean from 1993 to 2002, we investigated historical changes of (1) species composition (albacore, bigeye and yellowfin) of the fishery, (2) distribution of number of fish per set using operational logbook data and (3) market price in Japanese fishing ports, and amount of import. 2. MATERIALS AND METHODS In this paper, two kinds of data were mainly used. One is the Annual Report of Catch Statistic on Fishery and Aquaculture published by the Statistics and Information Department, Ministry of Agriculture, Forestry and Fisheries (SID report). This report provides comprehensive statistic for Japanese fisheries including catch, number of vessel, and market price by species. The amount of catch by species from 1970 and the market prices from 1977 were used. The market price is based on information from large number of fishing port (155 ports in 2011). The other is logbook database which has been compiled at National Research Institute of Far Seas Fisheries (NRIFSF) based on the logbook mandatory submitted by fishermen. The databases for LL vessels larger than 20 GRT (large vessel) and for LL of 10-19 GRT (small vessel) are available for 1952-2011 and 1994-2011, respectively. The coverage rates of logbooks for large and small vessel were near 100% and about 70%, respectively (Matsumoto et al. 2013). In this document, the catch in number and effort was not raised for small vessel. For the species composition analysis the Japanese longline catch and effort statistics from 1952 up to 2011 were used. The amounts of catch by species (albacore yellowfin and bigeye) in this document are estimated by same procedure documented in Satoh et al (2012) using SID report and logbook database. We used trade statistics of Japan Ministry of Finance for amount of import of frozen albacore, yellowfin and bigeye from 1988 (http://www.customs.go.jp/toukei/info/). All statistics except for trade statistics for 2011 and 2012 in this report were preliminary. 3. RESULTS AND DISCUSSIONS 3 3.1. Species composition The number of large longline vessel and the number of hooks had decreased consistently since 1994 (Fig. 1). On the other hand, the number of small vessel and the number of hooks had slightly increased since 1994. The fishing ground for the large vessel distribute all over the world including the North Pacific Ocean, small vessels operate in the vicinity of Japan (Appendices 1, 2). The proportion of effort for the large vessel by sea area (the Atlantic Ocean, the Indian Ocean, North Pacific Ocean (10-40N) and other part of the Pacific Ocean) indicated that the proportion for the North Pacific Ocean did not change from 1993 to 2002 (Fig. 2) and shifting of effort from other area to the north Pacific was not clear. Therefore we should focus on the North Pacific Ocean. The amount of albacore was higher from 1993 to 2002 for the both vessel type (Fig. 3). The amount of bigeye and yellowfin decreased in the same period for the both vessel type. The historical trend for species composition for the both vessel type represented complementary relationship between albacore and bigeye (Fig. 4). In this period with higher albacore CPUE, the proportion for albacore was high and the proportion for bigeye was low. In this period (from 1993 to 2002) the relatively large catch of albacore for the large vessel was detected in 2nd and 3rd quarter, whereas catches for bigeye and yellowfin in the same season did not occur (Fig. 5). Such elongation of fishing season for albacore often occurred before 1970 when the fishery mainly targeted albacore. For the small vessel, there was no large difference between the period from 1993 to 2002 and after 2003(Fig. 6), partially because the catch of albacore for the small vessel remained much higher since 1994 (Fig. 3). 3.2. Number of fish per set The proportion of zero catch (zero fish per set) for albacore of large vessel from 1993 to 2002 was lower than other years especially in 2nd and 3rd quarter (Fig. 7). The proportion of medium catch, more than one fish to less than 20 fish per set, did not change between the period (1993 to 2002) and other years. The proportion for large catch, more than 20 fish to less than 100 fish per set, increased in this period in all four quarters. The proportion for more than 100 fish per set in this period drastically increased in main fishing season (1st and 4th quarter). Such high proportion was also observed before 1970. For bigeye and yellowfin in this period (Figs. 8, 9), the proportions of zero catch per set increased and the proportion of medium catch (>=1 and <20 fish per set) decreased. Same analysis was applied for the small vessel (Figs. 10-12), the proportion for more than 100 fish per set from 1994 to 2002 in 1st quarter was larger than after 2003, and the zero catch for yellowfin increased and the proportion for medium catch (>=1 and <20 fish per set) decreased. 3.3. Market price and amount of import Market prices (yen kg-1) for fresh and frozen albacore in this period from 1993 to 2002 showed stable, for fresh albacore was from 331 yen kg-1 in 1993 to 278 yen kg-1 in 2002 (Fig. 13). The prices for fresh bigeye was 1,609 (yen kg-1) in 1993 and then decreased to 1,006 (yen kg-1) in 2002, which is about 40% discount. The products of the market price and amount of catch are total value of albacore and bigeye, which is roughly 4 considered as total quantity demanded for these species. The main usages for albacore and bigeye are for canning and sashimi, respectively, thus it is questionable that albacore can replace bigeye straightforward. However in this period the total quantity demanded for albacore and bigeye increased and decreased, respectively (Fig. 14). Japan had experienced long business depression in this period, therefore Japanese consumer may tend to select more reasonable tuna under the tight economic times. Total catch for these tuna species by Japanese fishery, including longline, purse seine, pole and-line, etc, revealed decreasing of amounts of catch for bigeye and yellowfin. Total amount of import for frozen yellowfin showed downward trend from 1994 to 1999. In addition, unfortunately we cannot detect statistics of import for bigeye in this period (Fig. 15). Therefore the decreasing of demand for bigeye could be derived from shortage in supply for bigeye, and the shortage was not adequately filled with yellowfin, thus albacore should partially compensate the deficiency of bigeye in this period. The directivity for albacore could be induced by shortage of supply of bigeye around 1992, where stock status of bigeye had become worse in many areas (Appendices 3-6, WCPO; Davies et al (2011), EPO; Aires-da-Silva and Maunder (2012b), IDO; Nishida and Rademeyer (2011), ATL; Anonymous (ICCAT 2012b)). The first choice for the replacement may be yellowfin, however amount of catch for yellowfin of Japanese fishery and amount of import did not increase in this period. Their stock status in early 1990 had become worse or was stable (Appendices 7-10, WCPO; Langley et al (2011), EPO; Aires-da-Silva and Maunder (2012a), IDO; Langley et al (2012), ATL; Anonymous (ICCAT 2011a)). Just at that time stock size of the North Pacific albacore had start to increase, which leaded to high availability of albacore. The good catch of albacore did not result in falling down of their market price due to weak supply of bigeye and yellowfin. The stable market price of albacore is sufficient reason for Japanese fishermen to continue to target albacore. In summary, four pieces of evidence revealed the operation of targeting albacore of Japanese longline fishery in the North Pacific Ocean increased in this period from 1993 to 2002. First, the historical trend for species composition represented the proportion for albacore was high and the proportion for bigeye was low in this period. Second, elongation of fishing season for albacore of the large vessel occurred for the large vessel, which had been often observed before 1970 when the fishery mainly targeted albacore. Third, the proportion of zero catch and more than 100 fish per set for albacore of the large vessel was lower and very high, respectively. Such high proportion was also observed before 1970. The last one, the total quantity demanded for albacore and bigeye increased and decreased, respectively. 4. REFERENCES Anonymous (ICCAT). 2011a. Report of the 2011 ICCAT yellowfin tuna stock assessment session 113pp. Anonymous (ICCAT). 2012a. Annual report of Japan. ANN-022/2012. 17pp. Anonymous (ICCAT). 2012b. Report of the standing committee on research and statistics (SCRS). PLE-104 / 5 2012 Anonymous (ISC). 2011. Stock assessment of albacore tuna in the North Pacific Ocean in 2011. Report of the albacore working group stock assessment workshop. International Scientific Committee for Tuna and Tuna-like Species in the North Pacific Ocean. 4-11 June 2011 Shizuoka, Japan. 143pp. Aires-da-Silva, A. and Maunder M.N. 2012a. Status of yellowfin tuna in the eastern Pacific Ocean in 2011 and outlook for the future. SAC-03-05. 12pp. Aires-da-Silva, A. and Maunder M.N. 2012b. Status of bigeye tuna in the eastern Pacific Ocean in 2011 and outlook for the future. SAC-03-06. 12pp. Davies, N., Hoyle, S., Harley S., Langley, A., Kleiber, P. and Hampton, J. 2011. Stock assessment of bigeye tuna in the western and central Pacific Ocean. WCPFC-SC7-2011/SA-WP-02. 133pp. Langley, A., Hoyle, S. and Hampton, J. 2011. Stock assessment of yellowfin tuna in the western and central Pacific Ocean. WCPFC-SC7-2011/SA-WP-03. 135pp. Langley, A., Herrera, M. and Million, J. 2012. Stock assessment of yellowfin tuna in the Indian Ocean using MULTIFAN-CL. IOTC–2012–WPTT14–38 Rev_1. 72pp. Matsumoto, T. 2012. Review of Japanese longline fishery and its albacore catch in the Indian Ocean. IOTC/2012/WPTmT04/09. 23pp. Matsumoto, T., Kiyofuji, H. and Okamoto, H. 2013. Suggestion of alternative estimation of albacore catch by Japanese coastal longline fishery to apply to stock synthesis model. ISC/13/ALBWG/12. 12pp. Nishida, T. and Rademeyer, R. 2011. Stock and risk assessments on bigeye tuna (Thunnus obesus) in the Indian Ocean based on AD Model Builder implemented Age-Structured Production Model (ASPM). IOTC-WPTT13-2010-42 (rev. 2). 23pp. Satoh, K., Uosaki, K., Matsumoto, T. and Okamoto, H. 2012. A review of Japanese albacore fisheries in the North Pacific as of June 2012. ISC/12/ALBWG-3/02. 15pp. 6 small vessel (10‐19 GRT) large vessel (>=20 GRT) Number of vessels 500 400 300 200 100 0 1995 2000 2005 small vessel (10‐19 GRT) 2010 large vessel (>=20 GRT) Number of hooks (x 1000) 200,000 150,000 100,000 50,000 0 1981 1985 1990 1995 2000 2005 2010 Fig. 1 Historical changes of number of active vessel (upper) and number of hooks (lower) by vessel size of 1.0 the Atlantic Ocean the Indian Ocean 0.8 other area of the Pacific Ocean northwestern Pacific Ocean (10‐40N) 0.6 0.4 0.2 0.0 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 proportion of effort (number of hooks) Japanese longline in the North Pacific Ocean. The period with higher CPUE represent blue shaded area. Fig. 2 Historical changes of proportion of effort (number of hooks) by Ocean and area. The period with higher CPUE represent blue shaded area. 7 North Pacific (large vessel) catch by species 70000 ALB BET YFT 60000 50000 40000 30000 20000 10000 0 1970 1975 1980 1985 1990 1995 2000 2005 2010 2000 2005 2010 North Pacific (small vessel) catch by species 30000 ALB BET YFT 25000 20000 15000 10000 5000 0 1970 1975 1980 1985 1990 1995 Fig. 3 Amount of catch (ton) by species of Japanese longline operated in the North Pacific Ocean. Upper panel for large vessel (distant water + offshore water, >=20GRT), lower panel for small vessel (coastal water, 10-19 GRT). The period with higher CPUE represent blue shaded area. proportion of catch by species large vessel 0.8 ALB BET YFT 0.6 0.4 0.2 0.0 1970 1975 1980 1985 1990 1995 2000 2005 2010 1995 2000 2005 2010 proportion of catch by species small vessel 0.8 ALB BET YFT 0.6 0.4 0.2 0.0 1970 1975 1980 1985 1990 Fig. 4 Proportion of amount of catch by species of Japanese longline operated in the North Pacific Ocean. Upper panel for large vessel (distant water + offshore water; >=20GRT), lower panel for small vessel (coastal water, 10-19 GRT). The period with higher CPUE represent blue shaded area. 8 (A) large vessel, effort No. of hooks (x 1000) 60000 Q1 Q2 Q3 Q4 40000 20000 (B) 2009 2006 2003 2000 1997 1994 1991 1988 1985 1982 1979 1976 1973 1970 1967 1964 large vessel, albacore 800 No. of fish (x 1000) 1961 1958 1955 1952 0 Q1 Q2 Q3 Q4 600 400 200 (C) 2009 2006 2003 2000 1997 1994 1991 1988 1985 1982 1979 1976 1973 1970 1967 1964 large vessel, bigeye 400 No. of fish (x 1000) 1961 1958 1955 1952 0 Q1 Q2 Q3 Q4 200 1988 1991 1994 1997 2000 2003 2006 2009 1991 1994 1997 2000 2003 2006 2009 1985 1982 1979 1976 1973 1970 1967 1964 1961 large vessel, yellowfin 200 No. of fish (x 1000) 1988 (D) 1958 1955 1952 0 Q1 Q2 Q3 Q4 100 1985 1982 1979 1976 1973 1970 1967 1964 1961 1958 1955 1952 0 Fig. 5 Historical changes of effort (A; number of hooks (x1000)), (B) albacore, (C) bigeye and (D) yellowfin by quarter caught by Japanese large longline vessel in the North Pacific Ocean (10-40N). The period with higher CPUE represent blue shaded area. 9 (A) small vessel, effort Q1 Q2 Q3 Q4 No. of hooks (x 1000) 30000 20000 10000 (B) small vessel, albacore Q1 Q2 Q3 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 0 Q4 No. of fish (x 1000) 800 600 400 200 (C) small vessel, bigeye Q1 Q2 Q3 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 0 Q4 No. of fish (x 1000) 100 80 60 40 20 (D) small vessel, yellowfin Q1 Q2 Q3 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 0 Q4 No. of fish (x 1000) 80 60 40 20 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 0 Fig. 6 Historical changes of effort (A; number of hooks (x1000)), (B) albacore, (C) bigeye and (D) yellowfin by quarter caught by Japanese small longline vessel in the North Pacific Ocean (10-40N). The period with higher CPUE represent blue shaded area. 10 large vessel, albacore, zero per set (A) 1.0 Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 (B) large vessel, albacore, >=1 and < 20 fish per set 1.0 Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 (C) large vessel, albacore, >=20 and < 100 fish per set 0.6 proportion Qt1 Qt2 Qt3 Qt4 0.4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 (D) large vessel, albacore, >=100 fish per set 0.2 proportion Qt1 Qt2 Qt3 Qt4 0.1 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 Fig. 7 Proportion of catch number per set of albacore by quarter caught by Japanese large longline vessel in the North Pacific Ocean. (A) case for zero catch per set, (B) case for 1-19 fish per set, (C) case for 20-99 fish per set, (D) case for more than 100 fish per set. The period with higher CPUE represent blue shaded area. For each quarter the sum of proportion from four panels is 1. 11 large vessel, bigeye, zero per set (A) 0.8 Qt1 Qt2 Qt3 Qt4 proportion 0.6 0.4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 (B) large vessel, bigeye, >=1 and < 20 fish per set 1.0 Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 (C) large vessel, bigeye, >=20 fish per set 0.4 proportion Qt1 Qt2 Qt3 Qt4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 Fig. 8 Proportion of catch number per set of bigeye by quarter caught by Japanese large longline vessel in the North Pacific Ocean. (A) case for zero catch per set, (B) case for 1-19 fish per set, (C) case for more than 20 fish per set. The period with higher CPUE represent blue shaded area. For each quarter the sum of proportion from three panels is 1. 12 large vessel, yellowfin, zero per set (A) 1.0 Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 (B) large vessel, yellowfin, >=1 and < 20 fish per set 1.0 Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 (C) large vessel, yellowfin, >=20 fish per set 0.4 proportion Qt1 Qt2 Qt3 Qt4 0.2 1952 1954 1956 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 0.0 Fig. 9 Proportion of catch number per set of yellowfin by quarter caught by Japanese large longline vessel in the North Pacific Ocean. (A) case for zero catch per set, (B) case for 1-19 fish per set, (C) case for more than 20 fish per set. The period with higher CPUE represent blue shaded area. For each quarter the sum of proportion from three panels is 1. 13 (A) 1.0 small vessel, albacore, zero per set Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 (B) 1.0 small vessel, albacore, >=1 and < 20 fish per set Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 (C) 1.0 small vessel, albacore, >=20 and < 100 fish per set Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 (D) proportion 0.4 small vessel, albacore, >=100 fish per set Qt1 Qt2 Qt3 Qt4 0.2 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Fig. 10 Proportion of catch number per set of albacore by quarter caught by Japanese small longline vessel in the North Pacific Ocean. (A) case for zero catch per set, (B) case for 1-19 fish per set, (C) case for 20-99 fish per set, C) case for more than 100 fish per set. The period with higher CPUE represent blue shaded area. For each quarter the sum of proportion from four panels is 1. 14 (A) small vessel, bigeye, zero per set Qt1 1.0 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 (B) small vessel, bigeye, >=1 and < 20 fish per set 1.0 Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 (C) small vessel, bigeye, >=20 fish per set 0.2 Qt2 Qt3 Qt4 proportion Qt1 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Fig. 11 Proportion of catch number per set of bigeye by quarter caught by Japanese small longline vessel in the North Pacific Ocean. (A) case for zero catch per set, (B) case for 1-19 fish per set, (C) case for more than 20 fish per set. The period with higher CPUE represent blue shaded area. For each quarter the sum of proportion from three panels is 1. 15 (A) small vessel, yellowfin, zero per set Qt1 1.0 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 (B) small vessel, yellowfin, >=1 and < 20 fish per set 1.0 Qt1 Qt2 Qt3 Qt4 proportion 0.8 0.6 0.4 0.2 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 (C) small vessel, yellowfin, >=20 fish per set 0.2 Qt2 Qt3 Qt4 proportion Qt1 0.0 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Fig. 12 Proportion of catch number per set of yellowfin by quarter caught by Japanese small longline vessel in the North Pacific Ocean. (A) case for zero catch per set, (B) case for 1-19 fish per set, (C) case for more than 20 fish per set. The period with higher CPUE represent blue shaded area. For each quarter the sum of proportion from three panels is 1. 16 0 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 0 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 price (yen / kg) price (yen / kg) market price albacore fresh fresh panel) in Japanese fishing ports (155 ports in 2011). 17 flozen 600 400 200 market price bigeye flozen 2000 1500 1000 500 Fig. 13 Historical changes of market price of frozen and fresh for albacore (upper panel) and bigeye (lower catch*price (frozen) 120000 catch (total) 2011 2009 2007 2005 2003 2001 1999 1997 1995 1993 1991 0 1989 30000 1987 10000 1985 60000 1983 20000 1981 90000 1979 30000 amount of catch (ton) 40000 1977 amount of catch*price (x 1000) albacore 0 catch (total) 200000 2011 2009 2007 2005 2003 2001 1999 1997 1995 1993 1991 0 1989 50000 1987 50000 1985 100000 1983 100000 1981 150000 1979 150000 amount of catch (ton) catch*price (frozen) 200000 1977 amount of catch*price (x 1000) bigeye 0 Fig. 14 Historical changes of products of market price of frozen and total catch for albacore (upper panel) and bigeye (lower panel). The amounts of catch are total yield caught by Japanese fishing vessel of any fisheries in the North Pacific Ocean (north of equatorial). 18 total catch ALB 150,000 amount of catch (ton) BET YFT 100,000 50,000 2004 2006 2008 2010 2012 2004 2006 2008 2010 2012 2002 2000 1998 1996 1994 1992 1990 1988 0 total amount of import amount of import (ton) 150,000 100,000 50,000 2002 2000 1998 1996 1994 1992 1990 1988 0 Fig. 15 Recent trends of total catch of Japanese fishery (upper panel), total amount of import by species of Japan (lower panel). 19 Appendix 1 Geographical distribution of effort (x 1000 number of hooks; upper panel) and number of albacore (x 1000 fish; lower panel) of large vessel (>20 GRT) four periods (before 1974, 1975 to 1992, 1993 to 2002 and after 2003). 20 Appendix 2 Geographical distribution of effort (x 1000 number of hooks; upper panel) and number of albacore (x 1000 fish; lower panel) of small vessel (10-20 GRT) four periods (1994 to 2002 and after 2003). 21 Appendix 3 Annual average biomass of bigeye by region of western central Pacific Ocean (from figure 36 of Davies et al (2011)). The region 1 is vicinity of Japan. The regions 3 and 4 are tropical area, main fishing ground for bigeye. 22 Appendix 4 Annual spawning biomass of bigeye of eastern Pacific Ocean (from figure 5 of Aires-da-Silva and Maunder (2012a)). The black solid line indicates spawning biomass with fishing. Appendix 5 Annual spawning biomass of bigeye of the Indian Ocean (from figure 11 of Nishida and Rafemeyear (2011)). Appendix 6 Annual changes of relative abundance of bigeye of the Atlantic Ocean (from BET-figure 5 of Anonymous ICCAT (2012b)). 23 Appendix 7 Annual average biomass of yellowfin by region of western central Pacific Ocean (from figure 46 of Langley et al (2011)). Appendix 8 Annual spawning biomass of yellowfin of eastern Pacific Ocean (from figure 5 of Aires-daSilva and Maunder (2012b)). The black solid line indicates spawning biomass with fishing. Appendix 9 Annual spawning biomass of yellowfin of the Indian Ocean (from figure 31 of Langley et al (2012)). 24 Appendix 10 Annual changes of relative abundance of yellowfin of the Atlantic Ocean (from figure 17 of Anonymous ICCAT (2011)). 25