Cruise 1 of the M.V. N.B. Scofield for 1955. Cruise Report 55-S-1

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Cruise 2 of the N.B. Scofield for 1955. Cruise Report 55-S-2

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Cruise 3 of the N.B. Scofield for 1955. Cruise Report 55-S-3

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Cruise 4 of the N.B. Scofield for 1955. Cruise Report 55-S-4

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Tagging and recovery of tropical tunas 1955-1959

ENGLISH: Yellowfin and skipjack tuna occur in commercial quantities in the Eastern Pacific Ocean from California to Chile. They are captured in the high seas at distances from the mainland up to several hundred miles (see Alverson, 1960). The Inter-American Tropical Tuna Commission has been engaged for several years in research on the biology, ecology, and population dynamics of the stocks of these species supporting the commercial fishery, in order to elucidate the effects of the fishery and of fishery independent factors on their abundance and behavior, to provide the scientific basis for rational management of the fishery. An important aspect of this research is the investigation of the migrations of these species in the Eastern Pacific, and the determination of whether each consists of but a single population or is composed of various sub-populations. One direct means of approaching these problems is the tagging, and subsequent recovery, of specimens in the region of the commercial fishery. This also provides direct information on growth rates, by comparison of sizes of specimens at tagging and upon later recovery, and can furnish the basis of estimating rates of mortality. These are two of the important elements of the vital statistics of the tuna populations. SPANISH: El at��n aleta amarilla y el barrilete se encuentran en cantidades comerciales en el Oc��ano Pac��fico Oriental, desde California hasta Chile. Estos peces son capturados en alta mar a varios cientos de millas de distancia de tierra firme (ver Alverson, 1960). La Comisi��n Interamericana del At��n Tropical ha estado dedicada durante varios a��os a la investigaci��n de la biolog��a, ecolog��a y din��mica de las poblaciones de los stocks de las indicadas especies que mantienen la pesquer��a comercial, a fin de elucidar los efectos de ��sta y de los factores independientes de la explotaci��n sobre la abundancia y h��bitos de estos peces, para obtener una base cient��fica que permita una administraci��n racional de la pesquer��a. Un aspecto importante de esta investigaci��n es el estudio de los movimientos migratorios de estas especies en el Pac��fico Oriental, y la determinaci��n de que si cada una constituye una sola poblaci��n o est�� compuesta de varias subpoblaciones. Un medio directo de abordar estos problemas es el de la marcaci��n, y subsecuente recuperaci��n, de espec��menes en la regi��n de la pesquer��a comercial. Esto tambi��n proporciona una informaci��n directa sobre la tasa de crecimiento, por la comparaci��n de los tama��os de los espec��menes al ser marcados y recuperados m��s tarde y puede proveer la base para estimar las tasas de mortalidad. Estos son dos de los elementos importantes de las estad��sticas vitales de las poblaciones de at��n.

Changes in the size structure of the yellowfin tuna population of the tropical eastern Pacific Ocean from 1947 to 1955

ENGLISH: Morphometric studies by Godsil (1948), Godsil and Greenhood (1951), Royce (1953) and Schaefer (1952, 1955) have indicated that the yellowfin tuna of the Eastern Pacific are distinct from those of the Central Pacific. Tagging of yellowfin tuna by the California Department of Fish and Game, and by the Inter-American Tropical Tuna Commission in the Eastern Pacific, and by the Pacific Oceanic Fishery Investigations in the Central Pacific, have not yet revealed any migrations between these areas. Shimada and Schaefer (1956) have compared changes in population abundance and fishing intensity, considering the population in the Eastern Pacific as a separate entity. They conclude " ... the amount of fishing has had a real effect upon the stock of Eastern Pacific yellowfin tuna, taken in the aggregate, over the period studied. The evidence suggests also that for this species the intensity of fishing in some recent years has reached and might have even exceeded the level corresponding to the maximum equilibrium yield." Tagging experiments by the California Department of Fish and Game and by the Inter-American Tropical Tuna Commission have yielded returns in the order of one to five percent (Roedel 1954, and unpublished data of both agencies), a level much lower than that at which fishing intensity would be expected to noticeably affect the population size. These results are probably a reflection of the inadequacies of the present tagging methods, but they could lend doubt to the conclusions of Shimada and Schaefer. It is desirable, therefore, to examine other, independent, evidence as to the effects of fishing on the population. At the high levels of fishing intensity suggested by Shimada and Schaefer, in addition to changes in quantity, measurable changes would be expected to have occurred in the quality of the yellowfin tuna stocks, because the average age and size of the fish would have been reduced by the high mortality rates accompanying high fishing intensities. A continuing regular program of sampling catches and determining their length composition, to assess changes in the size composition of the stocks, was initiated by the Commission in 1954 but direct measurements are not available for the earlier, more dynamic period of growth of the fishery. Consequently, other, more general indications of possible changes in the size composition were sought. SPANISH: Los estudios morfom��tricos efectudos por Godsil (1948), Godsil y Greenhood (1951), Royce (1953) y Schaefer (1952, 1955), han demostrado que el at��n aleta amarilla del Pac��fico Oriental es distinto del que habita el Pac��fico Central. Los experimentos del Departamento de Pesca y Caza de California y de la Comisi��n Interamericana del At��n Tropical en el Pac��fico Oriental, as�� como los de las Investigaciones Pesqueras del Oc��ano Pac��fico en el Pac��fico Central,consistentes en la marcaci��n de atunes aleta amarilla, a��n no han puesto de manifiesto movimientos migratorios entre dichas ��reas. Shimada y Schaefer (1956) han hecho estudios comparativos sobre la abundancia de la poblaci��n y la intensidad de la pesca, considerando a la poblaci��n del Pac��fico Oriental como una entidad separada. Su conclusi��n es que " ... la intensidad de la pesca ha tenido un definido efecto sobre la poblaci��n del at��n aleta amarilla del Pac��fico Oriental, tomada en conjunto, a lo largo del per��odo estudiado. La evidencia de que se dispone sugiere as�� mismo que, por lo que hace a esta especie, la intensidad de la pesca en los ��ltimos a��os ha alcanzado y quiz��s a��n sobrepasado el nivel correspondiente a la m��xima pesca de equilibrio". Los experimentos de mar���caci��n del Departamento de Pesca y Caza de California y de la Comisi��n Interamericana del At��n Tropical han producido recuperaciones ,entre el uno y el cinco por ciento (Roedel 1954 y datos in��ditos de ambos organismos), lo que constituye un nivel mucho m��s bajo de aqu��l en que la intensidad de la pesca podr��a considerarse que afectar��a notablemente el tama��o de la poblaci��n. Estos resultados reflejan probablemente lo inadecuados que son a��n los m��todos de marcaci��n, pero ellos podr��an, quiz��, poner en tela de juicio las conclusiones de Shimada y Schaefer. Por lo tanto,es deseable examinar otras fuentes de evidencia independientes, relacionadas con el efecto que la pesca tiene sobre la poblaci��n. En efecto, si los altos ��ndices de pesca sugeridos por Shimada y Schaefer son correctos, es de esperar que, adem��s de los cambios en la magnitud de la poblaci��n, se hayan producido otros, concomitantes y sensibles, en la calidad de los stocks de at��n aleta amarilla, puesto que tanto el promedio de edad como el de tama��o de los individuos habr��an disminu��do debido a las elevadas tasas de mortalidad inherentes a las altas intensidades de pesca. En 1954 la Comisi��n inici�� un programa ininterrumpido para tomar muestras y determinar en ellas las frecuencias de tallas y evaluar de este modo los cambios correlativos que tuvieran lugar en los stocks pero, infortunadamente, este sistema de evaluaci��n directa no fu�� practicado en el per��odo anterior, que fu�� precisamente el de r��pida expansi��n de la pesquer��a. En tal virtud, hubo de ser necesario buscar indicios m��s generales referentes a los cambios posibles en la composici��n de tama��os. (PDF contains 20 pages.)

Schooling habits of yellowfin tuna (Neothunnus macropterus) and skipjack (Katsuwonus pelamis) in the Eastern Pacific Ocean, as indicated by purse seine catch records, 1946-1955

ENGLISH: These aspects of the schooling habits of the yellowfin and skipjack tuna may be investigated by means of the logbook records of the catches of individual sets of the nets of purse-seine vessels. For both purposes it must be assumed that a set is made, in each case, on a single school of fish. The study of school sizes based on these data requires the additional assumption either that the entire school is captured or that each set captures a constant fraction of the school upon which it is made. In this paper we report on the results of such investigations based on logbook records of the purse-seine fleet. SPANISH: Estos aspectos de los h��bitos gregarios de los atunes aleta amarilla y barrilete pueden ser investigados a base de los registros de bit��cora en que se anotan las pescas resultantes de cada una de las operaciones con la red de encierre que realizan los barcos rederos. Para ambos prop��sitos hay que suponer que las operaciones se efect��an, en cada caso, en un cardumen independiente. El estudio de los tama��os de los card��menes o manchas, a base de estos datos, requiere una suposici��n adicional: que el cardumen entero es capturado o, en su defecto, que en cada operaci��n con la red se pesca una fracci��n constante de la mancha objeto de la pesca. En el presente art��culo damos cuenta de los resultados de dichas investigaciones basadas en los registros de bit��cora que lleva la flota de embarcaciones que utilizan redes de encierre. (PDF contains 47 pages.)

Geographical distribution of the annual catches of yellowfin and skipjack tuna from the Eastern Tropical Pacific Ocean from vessel logbook records, 1952-1955

ENGLISH: The Inter-American Tropical Tuna Commission is engaged in scientific studies of the tuna resources of the Eastern Tropical Pacific Ocean. One of the most important aspects of these investigations is the evaluation of the effects of fishing upon the populations of yellowfin tuna (Neothunnus macropterus) and skipjack (Katsuwonus pelamis) of this region, based upon the analysis of quantitative records of fishing effort and catch. The systematic collection and compilation of statistical information on the operations and production of the tuna fishing Beet have, therefore, been essential parts of the research program since its inception in 1951. SPANISH: La Comisi��n Interamericana del At��n Tropical est�� dedicada al estudio cientifico de los recursos de at��n del Oc��ano Pacifico Oriental Tropical. Uno de los aspectos m��s importantes de las investigaciones es la evaluaci��n de los efectos de la pesca sobre las poblaciones de at��n aleta amarilla (Neothunnus macropterus) y barrilete (Katsuwonus pelamis) de esta regi��n, sobre la base del an��lisis de los registros cuantitativos del esfuerzo de pesca y captura respectiva. La recolecci��n sistem��tica y la compilaci��n de informaciones estadisticas sobre las operaciones y producci��n de la flota pesquera de at��n han sido, consecuentemente, de esencial importancia dentro de nuestro programa de trabajo desde su comienzo en 1951. (PDF contains 77 pages.)

Consideraciones sobre las percas (Percichthys colhuapiensis y P.trucha) de la Patagonia norte - A��os 1955 a 1957. Comparaciones con material de a��os recientes.

Este trabajo se basa en los muestreos sobre las percas (Percichthys sp) realizado entre los a��os 1955 a 1957 por Mar��a Luisa Fuster de Plaza y Enrique E. Boschi, ambos investigadores se desempa��aban en el Departamento de Investigaciones Pesqueras de la Direcci��n Nacional de Pesca, dependiente del Ministerio de Agricultura y Ganader��a de la Naci��n de entonces. Las tareas se llevaron a cabo principalmente en varios cuerpos de agua l��ntica y l��ticas de la regi��n de la Patagonia Norte (Provincias de R��o Negro, Neuquen y Chubut), y en la provincia de Mendoza. Consisten en datos morfom��tricos, desarrollo gonadal, fecundidad, contenidos alimenticios, planillas, dibujos, etc. de 80 ejemplares de percas. La autora tuvo a su cargo el an��lisis de los datos de esos muestreos y las comparaciones con estudios de material m��s reciente, correspondiente al lago Pellegrini, a partir de 1981.

Geographical distribution of yellowfin tuna and skipjack catches from the Eastern Tropical Pacific Ocean, by quarters of the year, 1952-1955

ENGLISH: In a previous Commission Bulletin, Shimada (1957) has described the geographical distribution of the yearly catches of yellowfin tuna (Neothunnus macropterus) and skipjack (Katsuwonus pelamis) from the Eastern Pacific Ocean for the period 1952 to 1955 inclusive, based on information obtained from logbook records of baitboats and purse-seiners. In view of the seasonal nature of the fishery in different areas, a summary of the catches by smaller time units may be of additional value. Accordingly, statistical data employed earlier by Shimada have been retabulated by quarters of the year and form the basis of the present report. SPANISH: En un Bolet��n anterior de la Comisi��n, Shimada (1957) hizo un estudio sobre la distribuci��n geogr��fica de las pescas anuales de at��n aleta amarilla (Neothunnus macropterus) y barrilete (Katsuwonus pelamis) del Oc��ano Pacifico Oriental, en el perlado comprendido por los a��os 1952 a 1955 inclusive. Dicho estudio fu�� hecho sobre la base de la informaci��n obtenida en los registros de las bit��coras de los barcos carnaderos y rederos. Pero en vista de la naturaleza que imprimen las estaciones a la pesquer��a en las diferentes ��reas se ha considerado que podr��a tener valor complementario un resumen de las pescas en unidades de tiempo menores. De acuerdo con este criterio, los datos estad��sticos empleados antes por Shimada, se han tabulado de nuevo ahora, por trimestres, y constituyen siempre la base del presente informe. (PDF contains 49 pages.)

An oceanographic atlas of the Eastern Tropical Pacific Ocean, based on data from EASTROPIC Expedition, October-December 1955.

ENGLISH: EASTROPIC Expedition was a cooperative oceanographic study of the eastern tropical Pacific Ocean conducted during the period 2 October through 16 December 1955. The five participating agencies and the ships they operated were: Scripps Institution of Oceanography (SIO), Spencer F. Baird and Horizon; Pacific Oceanic Fisheries Investigations (POFI) of the U. S. Fish and Wildlife Service, now Honolulu Biological Laboratory (HBL) of the U. S. Bureau of Commercial Fisheries, Hugh M. Smith; California Department of Fish and Game, N. B. Scofield; the Peruvian Navy, Bondu; and the Inter-American Tropical Tuna Commission which operated no vessels but supplied equipment and personnel. In addition to these planned participations in EASTROPIC Expedition, valuable information was provided by CCOFI Cruise 5512 of the California Cooperative Oceanic Fisheries Investigations, conducted during the period 29 November -16 December 1955 with the two vessels Stranger and Black Douglas. While the observational programs of most of the agencies involved, in part, special hydrographic-biological studies of known features and processes in the region (see reports listed under Data Sources) the deployment of ships and therefore of observations was sufficient that EASTROPIC Expedition could be considered a survey of the eastern tropical Pacific. This report is concerned with that aspect of the Expedition and is a presentation in atlas form of most of the hydrographic data collected. For reasons given below, emphasis has been placed on the upper 300 m of the water column. SPANISH: La Expedici��n EASTROPIC es un estudio oceanogr��fico cooperativo del Oc��ano Pac��fico Oriental Tropical llevado a cabo durante el per��odo del 2 de octubre al 16 de d��c��embre de 1955. Las cinco agencias participantes y los barcos operados por ellas son los siguientes: Scr��pps Inst��tut��on of Oceanography (SIO) , Spencer F. Baird y Horizon; Pacific Oceanic Fisheries Investigat��ons (PO'FI) del U. S. Fish and Wildlife Service, ahora Honolulu Biological Laboratory (BHL) del U. S. Bureau of Commercial Fisheries, Hugh M. Smith; California Department of Fish and Game, N. B. Scofield; la Marina Peruana, Bondu; y la Comisi��n Interamericana del At��n Tropical que no dirigi�� ning��n barco pero proporcion�� equipo y personal. Adem��s de estas participaciones planeadas en la Expedici��n EASTROPIC, fu�� suministrada informaci��n de valor por el Crucero CCOFI 5512 del California Cooperative Fisheries Investigat��ons, llevado a cabo durante el per��odo del 29 de noviembre al 16 de diciembre de 1955 con los barcos Stranger y Black Douglas. Aunque los programas de observaci��n de la mayor��a de las agencias, comprendieron en parte estudios especiales hidrogr��ficos y biol��gicos de las caracter��sticas y de los procesos conocidos de la regi��n (v��ase los informes indicados bajo Fuente de Datos), el despliegue de los barcos, y por lo tanto, de las observaciones, fu�� suficiente para que la Expedici��n EASTROPIC pudiera ser considerada como una encuesta del Pac��fico Oriental Tropical. Este informe se refiere a este aspecto de la Expedici��n y es una presentaci��n, en forma de un atlas, de la mayor��a de los datos hidrogr��ficos recolectados. Por las razones que se dan a continuaci��n, se le di�� ��nfasis a los 300 m., superiores de la columna de agua. (PDF contains 136 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.)

Report of the Inter-American Tropical Tuna Commission for the year 1955

ENGLISH: This is the fifth year of investigations, by the Inter-American Tropical Tuna Commission, of the fisheries for tunas and tuna-bait fishes in the Eastern Pacific Ocean adjacent to the shores of the Americas. These investigations are being conducted by an international scientific staff, under the provisions of a Convention to which Costa Rica, Panama, and the United States are signatories. Other nations having an interest in these fisheries may adhere through exchange of correspondence with the present member governments. SPANISH: Este es el quinto a��o de investigaciones efectuadas por la Comisi��n Interamericana del At��n Tropical sobre las pesquer��as de at��n y de peces de carnada usados para la captura de ��ste, en la zona del Pac��fico Oriental adyacente a las costas de las Am��ricas. Estas investigaciones est��n a cargo de un grupo internacional de cient��ficos, de acuerdo 'con la Convenci��n de la que son signatarias Costa Rica, Panam�� y los Estados Unidos. Cualquier naci��n que tenga inter��s en estas pesquer��as, puede adherirse a la Convenci��n mediante un cambio de correspondencia con los Gobiernos Miembros. (PDF contains 95 pages.)

The diatoms of Longans lake-vegetation. Fossil diatom flora. [Translation from: Acta Phytogeographica Suecica 36 73-86, 1955. ]

Sediment samples were taken from Lake Langans in Sweden and fossilised diatoms analysed. Sample methods and environmental factors are discussed. Species with a characteristic occurrence are described. The article discusses diatom-thanatocoenoses as indicators of environment.

Some abundant Tendipedid species (Diptera, Tendipedidae) of the Amu-Darya drainage basin. Acalcarella shilova, gen.n. only [Translation from: Ent.Obozr. 34 313-322, 1955]

This document is a partial translation of taxonomic notes on two Diptera species (Acalcarella Shilova, Acalcarrella nucus) which were abundant in a survey of Tendipedid species (Diptera, Tendipedidae) of the Amu Darya drainage basin. These taxonomic notes of the larva, pupa and adults include drawings of the Acalcarella nucus larva.