AN EVALUATION OF ASSUMPTIONS ASSOCIATED WITH BLUE MARLIN DEPTH DISTRIBUTION TOWARDS THE POSSIBLE INCORPORATION INTO THE STANDARDIZATION OF CATCH AND EFFORT STATISTICS FOR USE IN STOCK ASSESSMENT 1

SUMMARY Attempts to improve the accuracy of stock assessments of blue marlin (Makaira nigricans) and white marlin (Tetrapturus albidus) have included efforts to standardize CPUE data derived from by-catches of the longline fisheries in the Atlantic Ocean. It has been suggested that by failing to account for the temporal changes in the relative vertical distribution of marlins and longline gear, a bias will be present in the CPUE analysis. This paper examines the estimation of CPUE under the assumption that blue marlin are restricted to a narrow depth and temperature range. RESUMEN En un intento de mejorar la precision de las evaluaciones de stock de aguja azul (Makaira nigricans) y aguja blanca (Tetrapturus albidus) se han hecho esfuerzos para estandarizar los datos de CPUE obtenidos partiendo de las capturas fortuitas de las pesquerias palangreras en el Atlantico. Se ha sugerido que al no tener en cuenta los cambios temporales en la distribucion vertical relativa de los marlines y el palangre, los analisis de CPUE contendran un sesgo. El documento examina la estimacion de la CPUE con el supuesto que la aguja azul se circunscribe a una escala limitada en cuanto a profundidad y temperatura. RESUME

[1]  O. Abe,et al.  Depth Measurements of Tuna Longline by Using Time-Depth Recorder , 1998 .

[2]  R. Brill,et al.  The standard metabolic rate of dolphin fish , 1995 .

[3]  B. Block,et al.  Depth and temperature of the blue marlin, Makaira nigricans, observed by acoustic telemetry , 1992 .

[4]  Barbara A. Block,et al.  Direct measurement of swimming speeds and depth of blue marlin , 1992 .

[5]  B. Sidell,et al.  Activities of key metabolic enzymes in the heater organs of scombroid fishes. , 1991, The Journal of experimental biology.

[6]  C. Greene,et al.  Oceanography: A view of the earth , 1987, IEEE Journal of Oceanic Engineering.

[7]  R. Brock.  A Contribution to the Trophic Biology of the Blue Marlin (Makaira nigricans Lacepede, 1802) in Hawaii , 1984 .

[8]  A. Baker.  Food of Marlins from New Zealand Waters , 1966 .

[9]  Donald S. Erdman.  The Sport Fishery for Blue Marlin off Puerto Rico , 1962 .

[10]  Hiroshi Okamura,et al.  Estimating the underwater shape of tuna longlines with micro-bathythermographs , 1999 .

[11]  Richard W. Brill,et al.  Selective advantages conferred by the high performance physiology of tunas, billfishes, and dolphin fish , 1996 .

[12]  H. Dewar,et al.  The aerobic capacity of tunas: Adaptation for multiple metabolic demands , 1996 .

[13]  E. Iversen,et al.  Growth rates of captive dolphin, Coryphaena hippurus, in Hawaii , 1995 .

[14]  E. Iversen,et al.  The abundance of cetaceans in California waters. Part I: ship surveys in summer and fall of 1991 , 1995 .

[15]  E. Hanamoto.  Effect of oceanographic environment on bigeye tuna [Thunnus obesus] distribution , 1987 .

[16]  James Willard Nybakken,et al.  Marine Biology: An Ecological Approach , 1982 .