582 The Japanese Atlantic Longline Fishery, 1965, and the Status of the Yellowfin Tuna and Albacore Stocks Mad' 'n.v i SPECIAL SCIENTIFIC REPORT-FISHERIES Na 582 UNITED STATES DEPARTMENT OF THE INTERIOR U.S. FISH AND WILDLIFE SERVICE BUREAxTof^COMMERCiArFIS^^ SPECIAL SCIENTIFIC REPORT-FISHERIES Robert L. Hacker, Editor Jane S, Hallett, Associate Editor Mary Fukuyama, Assistant Editor Betty M. Hoffman, Assistant Editor PUBLICATION BOARD John A. Guinan James H, Johnson Robert L. Hacker John M, Patton, Jr, John I. Hodges Frank T. Piskur Harvey Hutchings Edward A. Schaefers Leslie W, Scattergood, Chairman Special Scientific Report — Fisheries are preliminary or progress reports and reports on scientific investigations of restricted scope. Established as Special Scientific Reports in 1940, nos. 1 to 67 were issued from that date to 1949, when the new series. Special Scientific Report — Fisheries, with new serial numbering, was started. Special Scientific Report — Fisheries are distributed free to libraries, research institutions. State agencies, and scientists. UNITED STATES DEPARTMENT OF THE INTERIOR U.S. Fish and Wildlife Service BUREAU OF commercial FISHERIES The Japanese Atlantic Longline Fishery, 1965, and the Status of the Yellowfin Tuna and Albacore Stocks By JOHN P. WISE and WILLIAM W. FOX, JR. Contribution No. 86, Bureau of Commercial Fisheries Tropical Atlantic Biological Laboratory, Miami, Fla. 33149 United States Fish and Wildlife Service Special Scientific Report-.Fisheries No. 582 Washington, D. C. April 1969 The Japanese Atlantic Longline Fishery, 1965, and the Status of the Yellowfin Tuna and Albacore Stocks By JOHN P. WISE and WILLIAM W. FOX, JR., Fishery Biologists Bureau of Commercial Fisheries Tropical Atlantic Biological Laboratory, Miami, Florida 33149 ABSTRACT Fishing effort reached nearly 100 million hooks in 1965, a level which is more than the yellowfin tuna stocks can support and remain commercially productive. As catch rates for yellowfin tuna decrease, more and more fishing will be directed toward albacore. Data on catches and fishing effort by the Japanese Atlantic longline fleet have been published by Shiohama, Myojin, and Sakamoto (1965), and by the Fisheries Agency of Japan (1966, 1967a, 1967b). Analyses of part or all of the data have been carried out by Paiva (196ia, 1961b, 1962), Moraes (1962), Nakagome and Suzuki (1963), Lima and Wise (1963), Griffiths and Nemoto (1967), Le GuenandWise (1967), Sakamoto (1967), Wise ( 1968), and Wise and Le Guen (in press). The principal species (in numbers) in the fishery for the 10 years 1956-65 have been yellowfin tuna""" (41 percent), albacore (39 percent), bigeye tuna (11 percent), and blue marlin (2 percent) --all other species make up only about 7 percent of the catch (table 1). These proportions have not been constant --the catch figures for the first 3 years of fishing on a commercial scale (1957-59) were: yellow- fin tuna 77 percent, albacore 18 percent, big- eye tuna and blue marlin 2 percent each, all other species only 1 percent. The major reason for the change in species composition has been the decrease in catch rate of yellowfin tuna from nearly eight fish per 100 hooks in the Note. — Estimates of catch, effort, and catch per unit effort in this paper are the best currently available. They supersede estimates in Le Guen and Wise (1967), Wise and Le Guen (in press), and Wise (1968). Corrections are minor, except for new estimates for 1961 and 1962 based on information received from A. Suda of the Far Seas Fisheries Research Laboratory of the Fisheries Agency of Japan (personal communication). Suda pointed out cer- tain necessary corrections in the data for 1961 and 1962 as published by Shiohama, Myojin, and Sakamoto (1965). ■"^ Common names only are given in the orlginalJapanese reports. whole Atlantic in 1957-59 to just under one fish per 100 hooks in 1965. (We have assumed throughout this study that the part of the fleet included in the logs available for tabulation is representative of the effort, catch, and geographical distribution of the whole fleet.) Wise (1968) reviewed the development of the fishery from its beginning in 1956 through 1964, in the areas shown in figure l.He pointed out that major changes took place in the fishery in 1964, and showed these changes as com- parisons of percentages from 1963 to 1964. The same tendencies are apparent in the 1965 data compared with the 1963 data: 1964 vs. 1965 vs. 1963 1963 Fishing effort + 54% + 77% Yellowfin tuna catch - 1% + 5% Albacore catch + 88% + 59% Bigeye tuna catch + 21% +129% Blue marlin catch -13% - 52% The greatest percentage increases in fishing effort from 1963 to 1964 were in the Guianas, North Oceanic (West), Bahia, and Rio de Janeiro areas --all are western Atlantic areas and three of them are among the best regions for albacore. From 1963 to 1965 the largest percentage increases were in the areas of Benguela, North Oceanic (East), Gulf of Guinea, Guianas, and North Oceanic (West) (table 2). Fishing effort shifted from 1963 to 1964 to the western Atlantic and to good albacore areas, but the change from 1963 to 1965 was in the opposite direction, to the eastern Atlan- tic, slightly favoring better yellowfin tuna areas. Table 1 Summary of catch and effort in the Japanese Atlantic longllne fishery, 1956-65 [Estimates, adjusted for the whole fleet on the basis of sample in each year. Symbol p represents 500 fish or less.] Number of hooks Species Year Yellowfin tuna Albaoore Bigeye tuna Bluefin tuna Blue marlin White marlin Black marlin Other marlin Sword- fish Skipjack tuna Total fish Thousand hooks 131 3,376 8,001 15,312 20,727 26,660 54,921 55,004 84,998 97,580 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 12 259 746 1,098 1,159 980 991 886 876 929 1 32 100 357 452 430 1,102 1,134 2,134 1,804 0 9 15 45 71 243 367 285 344 651 0 0 0 3 7 4 54 67 63 58 0 9 10 23 27 43 112 96 84 44 0 1 1 7 11 38 113 1 87 1 163 ^ 130 0 0 0 0 0 1 3 1 0 0 0 3 4 6 12 28 68 2 51 2 118 2 117 0 1 1 2 3 11 20 24 31 43 0 0 0 0 0 0 0 1 2 3 13 314 877 1,541 1,742 1,778 2,829 2,632 3,815 3,779 Totals . 366,710 7,936 7,546 2,030 256 4^ 551 5 407 136 6 19,320 ^ Includes striped marlin 2 Includes spearflsh and sallfish Rank correlation between fishing effort and catch rates for 1965 shows that the fishermen directed their effort efficiently with respect to the total abundance of all species and to yellowfin tuna and albacore combined, but in- efficiently with respect either to yellowfin tuna or to albacore. This relation is consistent with the partial move in fishing effort back to yellowfin tuna areas in 1965 after the distinct shift in 1964 to albacore areas. Catches of yellowfin tuna and albacore by area are given in tables 3 and 4. Catch rates for yellowfin tuna, albacore, bigeye tuna, and blue marlin over the 10 years are shown in figure 2. Mean catch rates, 1956-65, for yellowfin tuna, albacore, and blue marlin for the II areas are presented in tables 5 to 7, (Only these three species show clear declines in apparent abundance.) The mean rate was de- termined by adding the rates for all the months in which the area was fished and dividing by the number of months. The rate of decline in apparent abundance for each species in each area was calculated as the slope of a straight line fitted to logarithms of monthly catch rates, beginning with the first month of fish- ing in the best year. If the correlation coeffi- cient (r) was significant at P = 0.05 level or less, the decline was accepted as real--other- wise it was rejected. Declines are apparent for yellowfin tuna in all 11 areas, for albacore in 5 of the 11 areas, and for blue marlin in 7 of the 11 areas. The nunnber of areas showing declines increased over the 1956-64 period (Wise, 1968), which itself showed an increased number of declines over the 1956-63 period (Wise and Le Guen, in press). In addition to the increased number of areas which show declines, the rates of de- cline themselves appear to be increasing for yellowfin tuna and blue marlin. We compared the decline rates calculated over 10 years of the fishery with the decline rates calculated over the first 8 years. Of the 20 comparisons possible for yellowfin tuna and blue marlin (fishing was negligible in the Gulf of Mexico before 1963), 11 show increases in declines or declines where none previously existed, 3 show no decline or equal decline, and only 6 have a decrease in rate of decline. In other words, the decline rates appear to be accele- rating for these two species. Le Guen and Wise (1967) estimated that an annual equilibrium yield of about 550,000 yellowfin tuna could be taken from the Gulf of Guinea, Guianas, North Oceanic (East), Cape Verde, Caribbean, and North Oceanic (West) areas (the best yellowfin tuna areas), with a total annual fishing effort of about 12 million hooks. They also estimated an annual equi- librium yield of about 165,000 yellowfin tuna from the rest of the Atlantic with an effort of about 3 million hooks. The catch of yellowfin tuna in the best yellowfin tuna areas in 1965 was some 720,000 fish taken with almost 56 million hooks. These figures represent a yield only 31 percent over, despite a fishing effort more than 360 percent over, the estimated equilibrium figure. The catch of yellowfin tuna in the rest of the Atlantic was about 213,000 fish in 1965, 29 100° W. 60 W 30° W. 50° N 30° K 30° S 50° S. 50° S. 100° W 60° W 30° W. - 0° Figure 1. — Areas used In this study. 30° E. percent over the optimum, caught by about 42 million hooks, almost 1,300 percent above the equilibrium level. A large part of the effort in the Bahia, Rio de Janeiro, Florida, and Benguela areas nnust have been directed at albacore, since these are the best albacore fishing areas (table 4). The widespread declines in catch rates and the apparent acceleration of decline rates for some species are consistent with constantly- increasing fishing pressure. From a very modest beginning in 1956, the number of hooks fished in the Atlantic by the Japanese long- liners rose to nearly 3 1/2 million in 1957. By 1962 this nunnber had increased l6-fold, and in 1965 it was nearly 100 million hooks or more than 25 times the 1957 effort (table 1). These 100 million hooks were fished by ap- proxinnately 150 Japanese longliners. Since then the number of Japanese longliners fish- ing in the Atlantic has decreased--in the first 3 months of 1968 about 75 Japanese longliners were fishing at any given time in the Atlantic. In recent years, however, substantial num- bers of longliners from other countries have entered the Atlantic tuna fisheries. The de- crease in numbers of Japanese longliners has been made up by about 50 South Korean long- liners, plus perhaps 20 or 30 longliners fronn other countries, including Cuba, Venezuela, and China (Taiwan). Reports are persistent that new vessels in addition to the longliners now fishing are being built or planned for Atlantic operations. Thus it seems likely that in 1968 the total level of fishing effort in the Atlantic by longline is comparable to the ap- proximately 100 million hooks fished by the Japanese in 1965. If decline rates for yellowfin tuna continue at the 1965 level (or accelerate), by mid-1970 the catch of yellowfin tuna per 100 hooks will be 0.5 fish or less in all areas, reducing what was a species of major importance to little more than an incidental catch. The result will be to focus nearly all of the fishing effort on albacore, the only other species sufficiently Table 2. — Distribution of fishing effort in the Japanese Atlantic longline fishery by year and area [Estimates, adjusted for the whole fleet on the basis of sample in each year.] Year GG GUI NOE OV BEN CAR NOW BAH RIO FLA CH Total 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 0 1,328 1,806 2,999 4,967 7,603 6,072 6,475 4,613 13,809 81 515 2,645 2,836 2,446 478 3,287 3,304 7,654 6,588 31 1,218 1,633 3,380 2,893 2,136 9,169 8,059 11,923 18,433 0 234 1,233 3,311 4,410 4,305 5,939 5,729 9,253 9,004 0 0 0 15 1,022 6,685 9,824 7,756 9,489 21,239 0 5 290 258 330 92 1,324 2,560 2,627 1,909 0 0 26 92 140 91 1,864 3,135 8,899 6,231 19 74 368 2,404 4,512 5,186 13,335 8,195 14,441 8,311 0 0 0 17 7 84 997 2,803 5,268 5,258 0 0 0 0 0 0 3,109 6,555 8,274 6,279 0 2 0 0 0 0 0 433 2,556 519 131 3,376 8,001 15,312 20,727 26,660 54,921 55,004 84,998 97,580 Totals. 49,672 29,834 58,875 43,418 56,030 9,395 20,478 56,845 14,434 24,217 3,510 366,710 Table 3. — Catch of yellowfin tuna by the Japanese Atlantic longline fishery by year and area [Estimates, adjusted for the whole fleet on the basis of sanqjle in each year. Symbol 0 represents 500 fish or less.] Year GG GUI NOE CV BEN CAR NOW BAH RIO FLA cn Total 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 0 114 217 366 491 486 232 214 144 279 8 33 242 167 116 16 133 64 119 109 3 89 143 209 137 61 170 131 159 197 0 19 101 313 271 116 123 132 181 101 0 0 0 1 78 264 172 92 38 137 0 0 37 19 6 2 35 99 25 20 0 0 1 5 8 1 35 14 28 15 1 3 5 17 51 34 79 60 55 53 0 0 0 0 0 0 3 3 10 4 0 0 0 0 0 0 10 50 30 6 0 0 0 0 0 0 0 25 88 8 12 259 746 1,098 1,159 980 991 886 876 929 Totals . 2,543 1,007 1,299 1,357 782 243 107 358 20 96 121 7,936 Table 4. --Catch of albacore by the Japanese Atlantic longline fishery by year and area [Estimates, adjusted for the whole fleet on the basis of sample in each year. Symbol 0 represents 500 fish or less.] Year GG GUI NOE CV BEN CAR NOW BAH RIO FLA GM Total 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 0 6 9 27 31 50 26 21 7 19 1 7 38 41 29 7 37 30 61 42 0 15 19 31 20 8 42 34 154 240 0 2 3 4 2 3 4 9 11 19 0 0 0 0 29 73 210 194 602 799 0 0 2 6 14 2 24 32 26 10 0 0 1 2 1 3 56 136 309 156 0 2 28 245 325 281 509 219 414 172 0 0 0 1 0 4 58 134 239 209 0 0 0 0 0 0 136 324 310 138 0 0 0 0 0 0 0 1 1 0 1 32 100 357 452 430 1,102 1,134 2,134 1,804 Totals . 196 293 563 57 1,907 116 664 2,195 645 908 2 7,546 2 i.ol- O O X o O 0.6 S 0.2 - • Bige/e tuna • • ^^ y^ "^ • - • ^ • • • 1 1 • 1 1 1 j_ 1 1 1 1/5 O o X 0.4 - Blue Marlin o o - • a: I ■"^ ■*^ 10 u. n 1 • ..J_ • — 1_ I 1 i 1 t - 1956 57 58 59 60 b\ 62 63 64 65 Year 1956 57 58 59 60 61 62 63 64 65 Year Figure 2.~Catch per 100 hooks, 4 principal species, whole Atlantic Ocean, Japanese Atlantic longUne fishery, 1956-65. Table 5. — Catch rates and rates of decline for yellowfin tuna, Japanese Atlantic longline fishery, 1956-65 Area Mean catch rate Catch rate, best year Rate of decline ■■■ Coeff. of correlation Degrees of ■ freedom GG GUI NOE CV CAR CM BEN NOW BAH FLA RIO Fish per 5.5 4.5 3.8 3.3 2.9 2.8 2.7 1.5 1.4 0.9 0.2 100 hooks 11.5 (1958) 9.5 (1956) 8.2 (1958) 7.9 (1958) 9.3 (1958) 3.8 (1963) 8.0 (1960) 4.8 (1959) 6.0 (1957) 2.6 (1963) 1.0 (1962) 0.011 .009 .014 .011 .010 .030 .018 .017 .008 .033 .024 -0.703** -. 840** -.751** -.608** -.627** -.662** -.569** -.761** -.452** -.600** -.566** 73 98 80 73 57 12 62 48 80 20 19 •"• Rate of decline calculated as slope of a straight line (shown here as absolute value) fitted to logarithms of monthly catch rates, beginning with the first month of fishing in the best year. **Highly significant (P = 0.01, or less). Table 6.--Catch rates and rates of decline for albaoore, Japanese Atlantic longline fishery, 1956-65 Area Mean catch rate Catch rate best year Rate of decline ■"■ Coeff. of correlation Degrees of freedom Fish per 100 hooks RIO. BAH. FLA. BEN. NOW. CAR. GUI. NOE. CV,. GG.. GM. . 7 5 8 7 A 2 1.0 0.6 0.5 0 A.2 (1963) -- 7.1 (1958) 0.010 3.2 (1964) — 5.0 (1964) — 2.9 (1965) -- 2.2 (1960, 62) —(from '60) 1.6 (1957) .003 1.8 (1964, 65) — 1.7 (1960) .012 0.6 (1961) .015 0.1 (1963) .034 Positive slope -0.519** I 77 -.455 I 15 Positive slope -.238 -.399** -.283* -.374** -.563** 45 92 59 50 12 Rate of decline calculated as slope of a straight line (shown here as absolute value) fitted to logarithms of monthly catch rates, beginning with the first month of fishing in the best year. *Significant (P= 0.05, or less). **Highly significant (P = 0.01, or less). Table 7. --Catch rates and rates of decline for blue marlin, Japanese Atlantic longline fishery, 1956-65 Area Mean catch rate Catch rate, best year Rate of decline-"- Coeff. of correlation Degrees of freedom Fish per 100 hooks BAH. GM. . RIO. GUI. CAR. FLA. NOW. NOE. GG.. CV.. BEN. ).4 .4 .2 .2 .2 .2 .2 .1 .1 ,1 0.9 .5 1.1 .5 .4 .3 .3 .3 .2 .2 .1 (1958) (1965) (1959) (1956) (1964-) (1963) (1961) (1957) (1957, '58) (1957, '62, '63) (1960, '63) 0.011 .006 .025 .009 .007 (from '57) .007 (from '57) .009 (from '60) -0.521** 77 .356 28 -.343** 98 Positive slope -.332 20 -.626** 38 -.492** 89 -.376** 84 -.342** 79 -.328** 62 •"■ Rate of decline calculated as slope of a straight line (shown here as absolute value) fitted to logarithms of monthly catch rates, beginning with the first month of fishing in the best year. **Highly significant (P = 0.01, or less). abundant to support a longline fishery. The question is whether the albacore stocks can bear such intense fishing. Of the major alba- core areas, only Bahia sho-ws a decline in alba- core catch rate--Rio de Janeiro, Florida, Benguela, and North Oceanic (West) do not (although there is a hint in the data that the Florida area may begin to show a decline rate in 1966). It is hard to iinagine, however, that a marked increase in fishing in these areas will not be reflected in declines in catch rates for albacore. A substantial lowering of the albacore catch rate combined with an already extremely low catch rate for yellowfin tuna will make a continuing viable Atlantic long- line fishery extremely doubtful. LITERATURE CITED FISHERIES AGENCY OF JAPAN. 1966. Annual report of effort and catch statistics by area on Japanese tuna long line fishery, 1963. Its Res. Div., 322 pp. 1967a. Annual report of effort and catch statistics by area on Japanese tuna long line fishery, 1964. Its Res. Div.. 379 PP. 1967b. Annual report of effort and catch statistics by area on Japanese tuna long line fishery, 1965. Its Res. Div., 375 pp. GRIFFITHS, RAYMOND C,, and TAKESHI NEMOTO. 1967, A preliminary study of the fishery for yellowfin and albacore tuna in the Carib- bean Sea and western Atlantic Ocean by longliners from Venezuela. (Spanish: Un estudio preliminar de la pesqueria para atun aleta amarilla y albacora en el Mar Caribe y el Oceano Atlantico occidental por palangreros de Vene- zuela.) Ser. Rec. Exp. Pesq. Repub. Venez. Min. Agr. Cria Invest. Pesq. 1(6): 208-274. LE GUEN, J. C, and J. P. WISE. 1967. M^thode nouvelle d'application du modele de Schaefer aux popula- tions exploitees d'albacores dans I'Atlantique. Cah. ORSTOM (Office Rech. Sci. Tech. Outre-Mer), Ser. Oceanogr. 5(2): 79-93. LIMA, FLAVIO RODRIGUES, and JOHN P. WISE. 1963. A first examination of the abundance and distribution of yellowfin and alba- core tuna in the western tropical At- lantic, 1957 to 1961. FAO (Food Agr. Organ. U.N.) Fish. Rep. 6(3): 1515- 1521. MORAES, MANOEL NINO DE. 1962. Development of the tuna fishery of Brazil and preliminary analysis of the first three years' data. Arq. Estac. Biol. Mar. Univ. Fed. Ceara 2(2): 35- 57. NAKAGOME, J., and S. SUZUKI. 1963. Seasonal and annual variation of the hooking -rate and annual variation of the catch-quantity of tuna and marlin in the tropical Atlantic Ocean. FAO (Food Agr. Organ. U.N.) Fish. Rep. 6 (3): 1279-1297. PAIVA, MELQuiADES PINTO. 196 la. Sobre a pesca dos atuns e afins nas dreas em exploracao no Atlantico tropical. Arq. Estac. Biol. Mar. Univ. Fed. Ceara' 1(1): 1-20. 196lb. Cartas de pesca para os atuns e afins do Atlantico tropical. Arq. Estac. Biol. Mar. Univ. Fed. Ceara 1(2): 1- 110. 1962. Actual status of the knowledge on the biology of tunas in offshore waters of the Brazilian coast. Bol. Estac. Biol. Mar. Univ. Fed. Ceara' 5, 10 pp. SAKAMOTO, HISAO. 1967. Distribution of bigeye tuna in the Atlantic Ocean. Rep. Nankai Reg. Fish. Res. Lab. 25, pp. 67-73. SHIOHAMA, TASHIO, MASAKO MYOJIN, and HISAO SAKAMOTO. 1965. The catch statistic data for the Japanese tuna long -line fishery in the Atlantic Ocean and some simple con- siderations on it. Rep. Nankai Reg. Fish. Res. Lab. 21, 131 pp. WISE, JOHN P. 1968. The Japanese Atlantic longline fishery, 1964, and the status of the yellowfin tuna stocks. U.S. Fish Wildl. Serv., Spec. Sci. Rep. --Fish. 568, 5 pp. WISE, JOHN P., and JEAN- CLAUDE LE GUEN. (in press) The Japanese Atlantic long-line fishery, 1956-1963. Proc. Symp. Oceanogr. Fish. Resour. Trop. Atl. - UNESCO/FAO. MS. #1858 MBL WHOl Ubran, - Sona.s As the Nation's principal conservation agency, the Depart- ment of the Interior has basic responsibilities for water, fish, wildlife, mineral, land, park, and recreational re- sources. Indian and Territorial affairs are other major concerns of America's "Department of Natural Resources." 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