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106H. BLUE MARLINThe best knowledge currently available indicates that blue marlin constitutes a single world-wide species, and that there is a singlestock of blue marlin in the Pacific Ocean. For this reason, statistics on catches are compiled, and analyses of stock status are made,for the entire Pacific Ocean.Blue marlin are taken mostly by longline vessels of many nations that fish for tunas and billfishes between about 50°N and 50°S.Lesser amounts are taken by recreational fisheries and by various other commercial fisheries.Small numbers of blue marlin have been tagged, mostly by recreational fishermen, with conventional tags. A few of these fish havebeen recaptured long distances from the locations of release. In addition, blue marlin have been tagged with electronic tags and theiractivities monitored for short periods of time.Blue marlin usually inhabit regions where the sea-surface temperatures (SSTs) are greater than 24°C, and they spend about 90% oftheir time at depths in which the temperatures are within 1° to 2° of the SSTs.The Deriso-Schnute delay-difference population dynamics model, a form of production model, was used to assess the status ofthe blue marlin stock in the Pacific Ocean. Data for the estimated annual total retained catches for 1951-1997 and standardizedcatches per unit of effort developed from catch and nominal fishing effort data for the Japanese longline fishery for 1955-1997were used. It was concluded that the levels of biomass and fishing effort were near those corresponding to the maximumsustainable yield (MSY).A more recent analysis of data from the same years, but using MULTIFAN-CL, was conducted to assess the status of blue marlin inthe Pacific Ocean and to evaluate the efficacy of habitat-based standardization of longline effort. There is considerable uncertaintyregarding the levels of fishing effort that would produce the MSY. However, it was determined that blue marlin in the Pacific Oceanare close to fully exploited, i.e. that the population is near the top of the yield curve. It was also found that standardization of effort,using a habitat-based model, allowed estimation of parameters within reasonable bounds and with reduced confidence intervalsabout the estimates.Even though blue marlin are a single stock in the Pacific Ocean, it is important to know how the catches in the eastern Pacific Ocean(Figure H-1) have varied over time. The fisheries in the eastern Pacific Ocean (EPO) have historically captured about 10 to 18% ofthe total harvest of blue marlin from the Pacific Ocean, with average annual catch since 2002 of about 3,600 t.A Pacific-wide assessment of blue marlin in collaboration with the Billfish Working Group of the International Scientific Committeefor Tuna and Tuna-like Species in the North Pacific Ocean (ISC) is planned for completion in 2010.
FIGURE H-1. Retained catches of blue marlin in the eastern Pacific Ocean, 1979-2007, by gear type.FIGURA H-1. Capturas retenidas de marlín azul en el Océano Pacífico oriental, 1979-2007, por arte de pesca.107
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COVER PHOTOGRAPH BY WAYNE PERRYMANF
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3FISHERY STATUS REPORT 7TUNAS AND B
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5INFORME DE LA SITUACIÓN DE LA PES
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7A. THE FISHERY FOR TUNAS AND BILLF
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10fisheries, and have been reported
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12line vessels.The estimated size c
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14Figure 2. Carrying capacity, in c
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16FIGURE A-2a. Average annual distr
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18.FIGURE A-4. Distributions of the
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20FIGURE A-6a. Estimated size compo
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Page 28 and 29:
26FIGURE A-9. Estimated catches of
Page 30 and 31:
28FIGURE A-11. Estimated size compo
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30TABLE A-2a. Estimated retained ca
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32TABLE A-2a. (continued)TABLA A-2a
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34TABLE A-2b. (continued)TABLA A-2b
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36TABLE A-3a. Catches of yellowfin
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381TABLE A-3c. Catches of skipjack
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40TABLE A-3e. Annual catches of big
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42TABLE A-4b. Preliminary estimates
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44TABLE A-6a. Annual retained catch
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46TABLE A-7. Estimated numbers of s
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48TABLE A-8. Types of floating obje
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50TABLE A-10. Numbers and well volu
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52TABLE A-11b. Estimates of the num
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54A. LA PESQUERÍA DE ATUNES Y PECE
Page 58 and 59: 56En la Tabla A-2a se presentan las
Page 60 and 61: 581.3. Composición por tamaño de
Page 62 and 63: 601.5. Descargas de atunes y bonito
Page 64 and 65: 62bodega en el mar (VEM), en miles
Page 66 and 67: 64when the true dynamics includes a
Page 68 and 69: 66FIGURE B-2. Estimated recruitment
Page 70 and 71: 68FIGURE B-4. Spawning biomass traj
Page 72 and 73: 70FIGURE B-6. Catches of yellowfin
Page 74 and 75: 72FIGURE B-8. Phase plot of the tim
Page 76 and 77: 74TABLE B-1. Estimates of the MSY o
Page 78 and 79: 76Es importante señalar que la cur
Page 80 and 81: 78FIGURE C-1. Total catches (retain
Page 82 and 83: 80C. ATÚN BARRILETESe ha usado un
Page 84 and 85: 82fishing mortality are expected to
Page 86 and 87: 84FIGURE D-3. Average annual fishin
Page 88 and 89: 86FIGURE D-5. Trajectory of the spa
Page 90 and 91: 88FIGURE D-7. Catches for 1975-2008
Page 92 and 93: 90FIGURE D-9. Phase plot of the tim
Page 94 and 95: 92D. ATÚN PATUDOEn la presente eva
Page 96 and 97: 946. Los resultados son más pesimi
Page 98 and 99: 96FIGURE E-1. Retained catches of P
Page 100 and 101: 98F. ALBACORE TUNAThere are two sto
Page 102 and 103: 100300 000250 000200 000t150 000100
Page 104 and 105: 102fue aproximadamente 0.75, nivel
Page 106 and 107: 104FIGURE G-1. Retained catches of
Page 110 and 111: 108H. MARLÍN AZULLa mejor informac
Page 112 and 113: 110FIGURE I-1. Retained catches of
Page 114 and 115: 112J. ECOSYSTEM CONSIDERATIONS1. In
Page 116 and 117: 114have been identified (by presenc
Page 118 and 119: 116Some marine mammals are adversel
Page 120 and 121: 118tors of stress, and removing liv
Page 122 and 123: 120Knowledge of the trophic ecology
Page 124 and 125: 1226. AGGREGATE INDICATORSRecogniti
Page 126 and 127: 124b. The incidental mortalities of
Page 128 and 129: 126FIGURE J-1. Simplified food-web
Page 130 and 131: 128FIGURE J-4. Trophic level estima
Page 132 and 133: 130cual no es incluida en los anál
Page 134 and 135: 132Especie y poblaciónMortalidad i
Page 136 and 137: 1342.7. Tiburones y otros peces gra
Page 138 and 139: 136condición de la población del
Page 140 and 141: 1387‰ con respecto a la línea de
Page 142 and 143: 140entre índices de asociación de
Page 144 and 145: 142b. En junio de 2003, la CIAT ado
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