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

(PDF contains 33 pages)

A study of the dynamics of the fishery for yellowfin tuna in the Eastern Tropical Pacific Ocean

(PDF contains 43 pages.)

Spawning of yellowfin tuna and skipjack in the Eastern Tropical Pacific, as inferred from studies of gonad development

(PDF contains 70 pages.)

Fecundity of yellowfin tuna (Thunnus albacares) and skipjack (Katsuwonus pelamis) from the Eastern Pacific Ocean

(PDF contains 36 pages.)

Surface currents of the Eastern Tropical Pacific Ocean

(PDF contains 39 pages.)

A generalized stock production model

(PDF contains 83 pages.)

Reproductive biology of black skipjack, Euthynnus lineatus, an Eastern Pacific tuna

(PDF contains 94 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.)

Some observations on bigeye tuna (Thunnus obesus) caught by the surface and longline fisheries for tunas in the Eastern Pacific Ocean

(PDF contains 58 pages.)

Data collected on tuna spawning survey cruise July 1-20, 1957: data report

Studies of gonads of yellowfin and skipjack tunas (Neothunnus macropterus and Katsuwonus pelamis) carried out by the Inter-American Tropical Tuna Commission indicate that during summer months the offshore area in the region of the Revilla Gigedo Islands is a spawning location for these two species (Schaefer and Orange, 1956). In July of 1957 a cruise "Tuna Spawning Survey" was made aboard the vessel ORCA to make plankton hauls and to collect ancillary data for the primary purpose of surveying abundance of tuna larvae in this region. (PDF contains 17 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.)