Analysis of variance and standardization of longline hook rates of bigeye (Thunnus obesus) and yellowfin (Thunnus albacares) tunas in the Eastern Pacific Ocean during 1975-1987

ENGLISH: Longline hook rates of bigeye and yellowfin tunas in the eastern Pacific Ocean were standardized by maximum depth of fishing, area, and season, using generalized linear models (GLM's). The annual trends of the standardized hook rates differ from the unstandardized, and are more likely to represent the changes in abundance of tunas in the age groups most vulnerable to longliners in the fishing grounds. For both species all of the interactions in the GLM's involving years, depths of fishing, areas, and seasons were significant. This means that the annual trends in hook rates depend on which depths, areas, and seasons are being considered. The overall average hook rates for each were estimated by weighting each 5-degree quadrangle equally and each season by the number of months in it. Since the annual trends in hook rates for each fishing depth category are roughly the same for bigeye, total average annual hook rate estimates are possible with the GLM. For yellowfin, the situation is less clear because of a preponderance of empty cells in the model. The full models explained 55% of the variation in bigeye hook rate and 33% of that of yellowfin. SPANISH: Se estandardizaron las tasas de captura con palangre de atunes patudo y aleta amarilla en el Océano Pacífico oriental por la profunidad máxima de pesca, área, y temporada, usando modelos lineales generalizados (MLG). Las tendencias anuales de las tasas de captura estandardizadas son diferentes a las de las tasas no estandardizadas, y es más que representen los cambios en la abundancia de los atunes en los grupos de edad más vulnerables a los palangreros en las áreas de pesca. Para ambas especies fueron significativas todas las interacciones en los MLG con año, profundidad de pesca, área, y temporada. Esto significa que las tendencias anuales de las tasas de captura dependen de cuál profundidad, área, y temporado se está considerando. Para la estimación de la tasa de captura general media para cada especie se ponderó cada cuadrángulo de 5 grados igualmente y cada temporada por el número de meses que contiene. Ya que las tendencias anuales en las tasas de captura para cada categoría de profundidad de pesca son aproximadamente iguales para el patudo, son posibles estimaciones de la tasa de captura anual media total con el MLG. En el caso del aleta amarilla, la situación es más confusa, debido a una preponderancia de celdas vacías en el modelo. Los modelos completos explican el 55% de la variación de la tasa de captura de patudo y 33% de la del aleta amarilla. (PDF contains 19 pages.)

A review of the Japanese longline fishery for tunas and billfishes in the Eastern Pacific Ocean, 1981-1987

ENGLISH: This report reviews the activity of the Japanese longline fishery in the eastern Pacific Ocean during the 1981-1987 period, extending the studies for the 1956-1980 period made by other investigators. The spatial and temporal distributions of fishing effort, catch, apparent abundance, sexual maturity, and size composition are examined for the principal species of tunas and billfishes taken by that fishery. The interaction between the surface and longline fisheries is discussed. SPANISH: En este informe se presenta un repaso de la actividad pesquera de barcos palangreros japoneses en el Océano Pacifico oriental durante el periodo de 1981-1987, extendiendo los estudios del periodo de 1956-1980 realizados por otros investigadores. Se examinan las distribuciones especial y temporal de les fuerzo de pesca, la captura, la abundancia aparente, la madurez sexual, y la composición por talla de las principales especies de atunes y picudos capturadas por dicha pesquería. Se comenta la nteracción entre las pesquerías de superficie y palangrera. (PDF contains 171 pages.)

Validation of daily growth increments and estimation of growth rates of larval and early juvenile black skipjack, Euthynnus lineatus, using otoliths

ENGLISH: Increments in otoliths (sagittae) were examined, using light and scanning electron microscopy, to determine ages and estimate growth rates of larval and early-juvenile black skipjack, Euthynnus lineatus. Larvae and juveniles were collected between 1987 and 1989 from coastal waters of Panama in the eastern Pacific Ocean. Results from a laboratory experiment indicated that immersion for 6 and 12 hours in a 200 mg/L solution of tetracycline hydrochloride adequately marks otoliths and that increments are formed daily in the sagittae of postflexion larvae and early juveniles. Further, survival rates of tetracycline-treated fish were not significantly different from those of control fish. Growth rates were derived from length-age relationships of 218 field-collected specimens ranging in size from 5.7 to 20.3 mm SL. A growth rate of 0.70 mm/d was estimated from the weighted regression of standard length on age for all specimens. This rate lies within the range reported for larvae and early juveniles of other species of subtropical and tropical scombrids. Growth rates of postflexion larvae and early juveniles were not significantly different between the rainy season in July-August 1988 and the dry, upwelling season in January-February 1989. Growth was, however, significantly more variable for older individuals in July-August than in January-February, and may correspond, in part, to seasonal patchiness of prey. The growth rates of the otoliths relative to fish length were also not significantly different between seasons; however, the otoliths were larger relative to the lengths of fish collected in the rainy season, which may reflect slower growth during earlier larval stages. SPANISH: Se examinaron incrementos en otolitos (ságitas), usando microscopia de luz y de barrido electrónico, a fin de determinar la edad y estimar las tasas de crecimiento de barriletes negros, Euthynnus lineatus, larvales y juveniles tempranos. Entre 1987 y 1989 se capturaron larvas y juveniles en las aguas costeras de Panamá en el Océano Pacífico oriental. Los resultados de un experimento de laboratorio indicaron que una inmersión de 6 a 12 horas de duración en una solución de 200 mg/L de hidrocloro de tetraciclina marca los otolitos adecuadamente y que los incrementos se forman a diario en las ságitas de larvas en postflexión y juveniles tempranos. Además, las tasas de supervivencia de los peces tratados con tetraciclina no fueron significativamente diferentes a aquellas de los peces de control. Se calcularon las tasas de crecimiento a partir de las relaciones de talla-edad de 218 especímenes de TE entre 5.7 y 20.3 mm capturados en el mar. Se estimó.una tasa de crecimiento de 0.70 mm/día a partir de la regresión ponderada de talla estándar sobre edad para todos los especímenes. Esta tasa cae dentro del rango reportado para larvas y juveniles tempranos de otras especies de escómbridos subtropicales y tropicales. Las tasas de crecimiento de larvas en postflexión y juveniles tempranos no fueron significativamente diferentes entre la temporada de lluvias en julio-agosto de 1988 y la temporada de sequía y afloramiento en enero-febrero de 1989. Sin emoargo, el crecimiento fue significativamente más variable para los individuos de mayor edad en julio-agosto que en enero-febrero, y quizás corresponda parcialmente a la irregularidad temporal de la abundancia de presas. Las tasas de crecimiento de los otolitos en relación a la talla de los peces tampoco fueron significativamente diferentes entre temporadas; sin embargo, los otolitos eran más grandes en relación a la talla en peces capturados en la temporada de lluvias, lo cual podría reflejar crecimiento más lento durante las etapas larvales más tempranas. (PDF contains 42 pages.)

Some aspects of the dynamics of populations important to the management of the commercial marine fisheries

(PDF contains 33 pages)

Surface currents of the Eastern Tropical Pacific Ocean

(PDF contains 39 pages.)

A generalized stock production model

(PDF contains 83 pages.)

Biometric comparison of the anchoveta, Cetengraulis mysticetus (Gunther), from ten localities of the Eastern Tropical Pacific Ocean

ENGLISH: It is important to the Inter-American Tropical Tuna Commission to know whether the anchoveta (Cetengraulis mysticetus), the principal tuna bait species in the Eastern Tropical Pacific Ocean, is composed of one or several populations. Earlier research indicated that, on the basis of significant differences in certain meristic counts, populations of this species in six of the major baiting localities between Mexico and Peru, should provisionally be considered as separate stocks. Since that time, additional collections of anchovetas have been obtained from these and other intervening localities. Purpose of the present study was to confirm the results of the earlier work, and to determine whether the differences in the meristic counts persisted from year to year, as well as to examine certain morphometric characters of the fish from these areas, and to learn whether the populations from the other localities are also separate entities. SPANISH: La Comisión Interamericana del Atún Tropical está interesada en saber si la anchoveta (Ceteugrautís mvsticetus}, la principal especie usada como cebo para la pesca del atún en el Océano Pacífico Oriental Tropical, está compuesta de una o de varias poblaciones. Investigaciones previas indicaron que, a base de diferencias significativas encontradas en ciertos caracteres numéricos, las poblaciones de esta especie en seis de las principales localidades entre México y Perú, podían ser consideradas provisionalmente como pertenecientes a "stocks'' separados. Desde entonces se han venido haciendo recolecciones adicionales de anchovetas en éstas y otras localidades intermedias. El propósito del presente trabajo ha sido confirmar los resultados obtenidos previamente, y determinar si las diferencias en los caracteres numéricos han persistido de un año a otro, así como examinar ciertos caracteres morfométricos en los peces de estas áreas, y resolver si las poblaciones de las nuevas localidades muestreadas son también entidades diferentes. (PDF contains 76 pages.)

Contributions to the biology of the engraulid Anchoa naso (Gilbert and Pierson, 1898) from Ecuadorian waters

ENGLISH: One phase of the duties of the Inter-American Tropical Tuna Commission is the gathering and interpretation of data concerning the life history of the commercially important bait species throughout the Eastern Pacific Ocean. During 1958 the Commission established a laboratory in Manta, Ecuador to study tuna. It was subsequently found that this fishery was dependent upon one species of anchovy, Anchoa naso, which was locally referred to as "colorado." During the calendar year 1959 approximately 380,000 scoops of bait were taken by the Manta tuna fleet (Schaefer, 1960), which at that time numbered about 23 vessels. Since then the fleet has increased by about 25 per cent and it is probable that the bait catch has increased also. Virtually nothing has been reported concerning the life history of this species. Hildebrand (1943) reviewed its taxonomy and reported standard lengths ranging from 32 to 135 mm. Peterson (1956) examined specimens from Central America and found them to range from 27 to 66 mm. He also indicated that the species spawned over a long period of time. The present report describes some aspects of the life history of Anchoa naso in Ecuadorian waters. The findings are based on 121 collections taken during the period March 1959 through June 1961. SPANISH: Una fase de las obligaciones de La Comisión Interamericana del Atún Tropical es la obtensión e interpretación de los datos concernientes a la historia natural de las especies de carnada comercialmente importantes en todo el Océano Pacifico Oriental. En el año de 1958 la Comisión estableció un laboratorio en Manta, Ecuador, para estudiar el atún. Se encontró subsecuentemente que esta pesquería dependía de una especie de anchoa, Anchoa naso, conocida localmente con el nombre de colorado. Durante el año calendario de 1959, la flota atunera de Manta, que en ese tiempo alcanzaba a unos 23 barcos, obtuvo aproximadamente 380,000 copas (scoops) de carnada (Schaefer, 1960). Desde entonces la flota ha aumentado en un 25 por ciento, y es probable que la captura de peces-cebo haya aumentado también. Nada se ha informado virtualmente sobre la historia natural de esta especie. Hildebrand (1943) revisó su taxonomia e informó sobre su longitud estándar, que varia entre los 32 y 135 mm. Peterson (1956) examinó especímenes de la América Central, y encontró que variaban entre los 27 y 66 mm. También indicó que la especie desova durante un largo periodo de tiempo. El presente informe describe algunos aspectos de la historia natural de la Anchoa naso en aguas ecuatorianas. Los hallazgos están basados en 121 recolecciones hechas durante el periodo de marzo de 1959 a junio de 1961. (PDF contains 30 pages.)

A temperature atlas of the Gulf of Panama, 1955-1959

The interests of the Inter-American Tropical Tuna Commission in the hydrography and biology of the Gulf of Panama have been adequately stated in the Commission's Bulletin series (Forsbergh, 1963; Howard, 1954; Howard and Landa, 1958; Peterson, 1961; Schaefer, 1953; Schaefer and Bishop, 1958; Schaefer, Bishop and Howard, 1958). The present report deals with data collected on 10 surveys made by Tuna Commission personnel for the purpose of describing seasonal upwelling by means of a study of the temperature structure of the Gulf of Panama, and a comparison of the thermal pattern during the dry, upwelling season (January to April) with that of the rainy season (May to December). Considerations of upwelling in the Gulf have been shown to be of interest and of probable biological consequence by Schaefer (1951) and by Simpson (1959). (PDF contains 60 pages.)

Oceanographic observations in the Gulf of Guayaquil, 1962-1964. Part I. Physical and Chemical

ENGLISH: During 1961 the government of Ecuador, with the financial assistance of the Special Fund of the United Nations and the technical assistance of FAO experts, initiated an extensive program of fisheries research centered in a fisheries institute established in Guayaquil. In cooperation with this program, and in connection with Ecuador's adherence in 196l to the Convention for the Establishment of an Inter-American Tropical Tuna Commission, a two-and-a-half year investigation of the ecology of the Gulf of Guayaquil and adjacent waters was started by the Inter-American Tropical Tuna Commission. SPANISH: En 1961 el gobierno del Ecuador con el apoyo financiro del Fondo Especial de las Naciones Unidas y la asistencia tenica de los expertos de la FAO, inicio un programa extensivo de investigacion pesquera centralizado en el instituto de pesquerias establecido en Guayaquil. En cooperacion con este programa y en conexion con la adhesion del Ecuador en 1961 a la Convencion para el establecimiento de una Comision Interamericana del Atun Tropical, se comenzo por esta misma Comision una investigacion de dos anos y medio sobre la ecologia del Golfo de Guayaquil y las aguas adyacentes. (PDF contains 1532 pages.)

Oceanographic observations for the Mazatlan Project: October 1966 - August 1967

ENGLISH: To learn more about the early life of yellowfin tuna in their immediate environment, the Inter-American Tropical Tuna Commission initiated a 2-year cooperative investigation with the Direccion General de Pesca e Industrias Conexas (DGP) of Mexico in August 1966. The project called for monthly cruises of about 5 days duration to be made in a triangular track between Mazatlan, Cape San Lucas and the Tres Marias Islands. Laboratory space for the field work was provided by the DGP in their biological station in Mazatlan and the research vessel Yolanda, property of the DGP, was made available for the monthly cruises. SPANISH: Con el fin de obtener un conocimiento mas avanzado sobre la vida temprana de estos atunes aleta amarilla, y del ambiente que los rodea, 1a Comision Interamericana del Atun Tropical inicio una investigacion colaborativa de 2 anos con la Direccion General de Pesca e Industrias Conexas (DGP) de Mexico, en agosto de 1966. El proyecto requirio cruceros mensuales de unos 5 dias de duracion para que fueran realizados en un rumbo triangular entre Mazatlan, Cabo San Lucas y las Islas Tres Marias. La Direccion General de Pesca ofrecio amab1emente las facilidades del laboratorio para el trabajo experimental en la estacion biologica de Mazatlan, y e1 barco de investigacion Yolanda para los cruceros mensuales. (PDF contains 256 pages.)

Report on estimating the size of dolphin schools, based on data obtained during a charter cruise of the M/V Gina Anne, October 11 -November 25, 1979

Estimates of dolphin school sizes made by observers and crew members aboard tuna seiners or by observers on ship or aerial surveys are important components of population estimates of dolphins which are involved in the yellowfin tuna fishery in the eastern Pacific. Differences in past estimates made from tuna seiners and research ships and aircraft have been noted by Brazier (1978). To compare various methods of estimating dolphin school sizes a research cruise was undertaken with the following major objectives: 1) compare estimates made by observers aboard a tuna seiner and in the ship's helicopter, from aerial photographs, and from counts made at the backdown channel, 2) compare estimates of observers who are told the count of the school size after making their estimate to the observer who is not aware of the count to determine if observers can learn to estimate more accurately, and 3) obtain movie and still photographs of dolphin schools of known size at various stages of chase, capture and release to be used for observer training. The secondary objectives of the cruise were to: 1) obtain life history specimens and data from any dolphins that were killed incidental to purse seining. These specimens and data were to be analyzed by the U.S. National Marine Fisheries Service ( NMFS ) , 2) record evasion tactics of dolphin schools by observing them from the helicopter while the seiner approached the school, 3) examine alternative methods for estimating the distance and bearing of schools where they were first sighted, 4) collect the Commission's standard cetacean sighting, set log and daily activity data and expendable bathythermograph data. (PDF contains 31 pages.)

Oceanographic observations in the Gulf of Guayaquil, 1962-1964. Part II. Biological, chemical and physical.

ENGLISH: During 1961 the government of Ecuador, with the financial assistance of the Special Fund of the United Nations and the technical assistance of FAO experts, initiated an extensive program of fisheries research centered in a fisheries institute established in Guayaquil. In cooperation with this program, and in connection with Ecuador's adherence in 1961 to the Convention for the Establishment of an Inter-American Tropical Tuna Commission, a two-and-a-half year investigation of the ecology of the Gulf of Guayaquil and adjacent waters was started by the Inter-American Tropical Tuna Commission. SPANISH: Durante 1961 el gobierno ecuatoriano con el apoyo financiero del Fondo Especial de las Naciones Unidas y la ayuda técnica de los expertos de la FAO, inició un programa extensivo de investigación pesquera, centralizado en el instituto pesquero establecido en Guayaquil. En cooperación con este programa y en conexión a la afiliaci6n del Ecuador a la Convención, en 1961, para el establecimiento de una Comisión Interamericana del Atún Tropical, Cue iniciada por la Comisión una investigación de dos aftos y medio sobre la ecología del Golfo de Guayaquil y de las aguas adyacentes. (PDF contains 501 pages.)

Oceanographic and meteorological observations for project Little Window: March 1970

ENGLISH: Project Little Window was planned to provide some answers to the important scientific question of whether or not the HRIR (high resolution infrared radiometer) sensors aboard NASA and NOAA satellites can provide useful data for much of the oceanographic community. The sensors aboard these satellites were designed in response to the initial needs of meteorologists for temperature measurements integrated over a distance of 5-10 nautical miles and extending over a range from 30°C to about -75°C (i2-4°C). To this end the sensors have been a very powerful tool to the meteorologist in preparing daily weather advisories and in carrying out research. SPANISH: El proyecto Little Window fue planeado para suministrar algunas respuestas al importante tema científico sobre si los captadores (ltsensors") infrarrojos de alta resoluci6n (IRAR) a bordo de los satélites NASA y NOAA, pueden o no proveer datos útiles para la mayor1a de los oceanógrafos. Los captadores a bordo de estos satélites fueron concebidos en respuesta a las necesidades iniciales de los meteor6logos para obtener mediciones de temperatura integradas sobre una distancia de 5-10 millas náuticas, y entre 30°c y aproximadamente -75°C (~2-4°C). Con este fin los captadores han sido un instrumento poderoso para el meteor6logo en la preparaci6n de las informaciones diarias de tiempo y en la realizaci6n de las investigaciones. (PDF contains 171 pages.)

Oceanographic, meteorological, satellite and aircraft observations for project Little Window 2: May 1971

ENGLISH: In May 1971, a joint united states - Mexican experiment, Project Little Window 2, (LW-2) involving data collected by satellite, aircraft and ship sensors was made in the southern part of the Gulf of California. LW-2 was planned as an improved and enlarged version of LW-l (conducted the previous year; Stevenson and Miller, 1971) with field work scheduled to be made within a 200 by 200 km square region in the Gulf of California. The purposes of the new field study were to determine through coordinated measurements from ships, aircraft and satellites, the utility of weather satellites to measure surface temperature features of the ocean from space and specifically to evaluate the high resolution infrared sensors aboard N~ 1, ITOS 1 and NIMBUS 4 and to estimate the magnitude of the atmospheric correction factors needed to bring the data from the spacecraft sensors into agreement with surface measurements. Due to technical problems during LW-2, however, useful data could not be obtained from ITOS 1 and NIMBUS 4 so satellite information from only NOAA-1 was available for comparison. In addition, a new purpose was added, i.e., to determine the feasibility of using an Automatic picture Transmission (APT) receiver on shore and at sea to obtain good quality infrared data for the local region. SPANISH: En mayo 1971, los Estados Unidos y México realizaron un experimento en conjunto, Proyecto Little Window 2 (LW-2), en el que se incluyen datos obtenidos mediante captadores de satélites, aviones y barcos en la parte meridional del Golfo de California. Se planeó LW-2 para mejorar y ampliar el proyecto de LW-l (conducido el año anterior; Stevenson y Miller, 1971), realizándose el trabajo experimental en una región de 200 por 200 km cuadrados, en el Golfo de California. El objeto de este nuevo estudio experimental fue determinar mediante reconocimientos coordinados de barcos, aviones y satélites la conveniencia de los satélites meteorológicos para averiguar las características de la temperatura superficial del océano desde el espacio, y especialmente, evaluar los captadores infrarrojos de alta resolución a bordo de NOAA 1, ITOS 1 Y NIMBUS 4, y estimar la magnitud de los factores de corrección atmosféricos necesarios para corregir los datos de los captadores espaciales para que concuerden con los registros de la superficie. Sin embargo, debido a problemas técnicos durante LW-2, no fue posible obtener datos adecuados de ITOS 1 y NIMBUS 4, as1 que solo se pudo disponer de la información de NOAA 1 para hacer las comparaciones. Además se quiso determinar la posibilidad de usar un receptor de Trasmisión Automático de Fotografias (APT) en el mar para obtener datos infarojos de buena calidad en la región local. (PDF contains 525 pages.)