Migrations of yellowfin tuna tagged off the southern coast of Mexico in 1960 and 1969

ENGLISH: The map method, the Jones method, the variance-covariance method, and the Skellam method were used to study the migrations of tagged yellowfin tuna released off the southern coast of Mexico in 1960 and 1969. The first three methods are all useful, and each presents information which is complementary to that presented by the others. The Skellam method, as used in this report, is less useful. The movements of the tagged fish released in 1960 appeared to have been strongly directed, but this was probably caused principally by the distribution of the fishing effort. The effort was much more widely distributed in 1970, and the movements of the fish released in 1969 appeared to have been much less directed. The correlation coefficients derived from the variance-covariance method showed that it was not random, however. The small fish released in the Acapulco and 10°N-100°W areas in 1969 migrated to the Manzanillo area near the beginning of February 1970. The medium and large fish released in the same areas in the same year tended to migrate to the southeast throughout the first half of 1970, however. SPANISH: El método de mapas, el de Jones, el de la variancia-covariancia y el de Skellam fueron empleados para estudiar las migraciones del atún aleta amarilla marcado y liberado frente a la costa meridional de México en 1960 y 1969. Los tres primeros métodos son todos útiles, y cada uno presenta información que complementa la presentada por los otros. El método de Skellam, conforme se usa en este informe, es menos útil. Parece que los desplazamientos de los peces marcados y liberados en 1960 hubieran sido fuertemente orientados, pero ésto probablemente fue causado principalmente por la distribución del esfuerzo de pesca. El esfuerzo se distribuyó más extensamente en 1970, y parece que los desplazamientos de los peces liberados en 1969 fueran menos orientados. Los coeficientes de correlación derivados del método variancia-covariancia indicaron, sin embargo, que no eran aleatorios. Los peces pequeños liberados en las áreas de Acapulco y los 10°N-100°W en 1969 migraron al área de Manzanillo a principios de febrero 1970. Los peces medianos y grandes liberados en las mismas áreas en el mismo año tuvieron, sin embargo, la tendencia a desplazarse al sudeste durante el primer semestre de 1970. (PDF contains 64 pages.)

Migrations of yellowfin and skipjack tuna in the Eastern Pacific Ocean as determined by tagging experiments, 1952-1964

ENGLISH: Totals of 59,547 tagged yellowfin and 90,412 tagged skipjack were released during 1952-1964 throughout the range of the fishery in the eastern Pacific Ocean during that period. Most of the fish were released from commercial baitboats, either on regular fishing trips or on chartered trips to catch fish for tagging. There we re 8,397 yellowfin and 4,381 skipjack returned from these releases. There appear to be two main groups of yellowfin in the eastern Pacific Ocean. There is considerable intermingling among the fish of the two groups, however. The fish of the northern group (west coast of Baja California, Gulf of California, and Revillagigedo Islands) first appear in the Revillagigedo Islands in about April, and migrate north along the Baja California coast during the spring and summer and south along that coast during the fall. Recruits to the southern group (Tres Marias Islands to northern Chile) appear at many points or continuously along most of the coast. The fish which first appear in the northern Panama Bight in April migrate rapidly northwest to Central America and Mexico and south to the Gulf of Guayaquil. There also appear to be two main groups of skipjack in the eastern Pacific Ocean. The fish of the northern group (west coast of Baja California, Gulf of California, and Revillagigedo Islands ) perform about the same migration as do the yellowfin of the same area, but most of the skipjack apparently then migrate to the central Pacific Ocean during the fall and/or winter. Recruits to the southern group (Central America to northern Chile) appear mostly in or near the Panama Bight. The fish which first appear in the northern Panama Bight in April migrate rapidly northwest to Central America and south to the Gulf of Guayaquil. The proportions which migrate in these directions vary considerably from year to year, this perhaps being dependent on differences in the sea-surface temperatures. SPANISH: Durante el período de 1952-1964 se liberó a través de todos los límites de distribución de la pesquería en el Océano Pacífico oriental un total de 59,547 aleta amarilla y 90,412 barriletes marcados. La mayoria de los peces fueron liberados de barcos de carnada comerciales, o en viajes regulares de pesca o en viajes en los que se fletaron los barcos para capturar atunes y marcarlos. De estas líberaciones se recapturaron 8,397 aleta amarilla y 4,381 barriletes. Parece que haya dos grupos principales de aleta amarilla en el Océano Pacífico oriental. Sin embargo, existe una entremezcla considerable entre los peces de los dos grupos. Los peces del grupo septentrional (costa occidental de Baja California, Golfo de California y Islas Revillagigedo) aparecen primero en las Islas Revillagigedo alrededor de abril, y durante la primavera y el verano se desplazan al norte a lo largo de la costa de Baja California y durante el otoño al sur a lo largo de la costa. Los reclutas del grupo meridional (Islas Tres Marias hasta el norte de Chile) aparecen en muchas partes o continuamente a lo largo de la mayoría de la costa. Los peces que aparecen primero en la región septentrional del Panamá Bight en abril se desplazan rápidamente al noroeste a la América Central y México y al sur al Golfo de Guayaquil. Parece también que existen dos grupos principales de barrilete en el Océano Pacífico oriental. Los peces del gr upo septentrional (costa occidental de Baja California, Golfo de California e Islas Revillagigedo ) realizan casi la misma migración que el atún aleta amarilla de la misma área, pero aparentemente la mayor parte del barrilete se desplaza luego al Océano Pacífico central durante el otoño y/o en el invierno. Los reclutas al grupo meridional (América Central al norte de Chile) aparecen en su mayoría en el Panamá Bight o cerca a este lugar. Los peces que aparecen primero en la región septentrional del Panamá Bight en abril se desplazan rápidamente al noroeste a la América Central y al sur al Golfo de Guayaquil. Las proporciones que se desplazan en estas direcciones varían considerablemente de año a año; tal vez esto depende en las diferencias de temperatura de la superficie del mar. (PDF contains 227 pages.)

Migrations of yellowfin tuna in the Eastern Pacific Ocean as determined from tagging experiments initiated during 1968-1974

ENGLISH: Data from tagging experiments initiated during 1968-1974 in the eastern Pacific Ocean were used to study the migrations of yellowfin tuna in that area. The map method, the parallel-area method, and the Jones method were employed in the analyses. The map method gives a useful impression of the distances and directions traveled, but does not express these parameters in quantitative terms. The parallel-area method is particularly useful for determining whether or not there is net movement in particular directions, i.e. inshore-offshore, east-west, or north-south. The first of these is of particular interest, as the incidence of smaller fish is much higher in the catches made inshore than in those made offshore, and it is desirable to know whether this is due to relatively greater abundance or to relatively greater vulnerability of the smaller fish in the inshore areas. If the former were the case an offshore movement of the fish as they grew older would probably be detected. Such a movement was not detected, however, so it appears likely that the differences in the catches of smaller fish in the inshore and offshore areas are due mainly to differences in vulnerability. Few or no east-west or north-south tendencies in the movements of the fish were detected. The Jones method indicates that the movement is not random, but reveals no pronounced directional tendencies. SPANISH: Se emplearon los datos de los experimentos de marcado, iniciados en el Océano Pacífico oriental durante 1968-1974 para estudiar los desplazamientos del atún aleta amarilla en esa zona. En los análisis se emplearon los métodos cartográficos, de las zonas paralelas y de Jones. El método cartográfico ofrece una idea útil sobre la distancia y dirección de los desplazamientos, pero no expresa estos parámetros en términos cuantitativos. El método de las zonas paralelas es particularmente conveniente para determinar si existe o nó un desplazamiento neto en una dirección especial, es decir, hacia la costa-fuera de la costa, este-oeste o norte-sur. El primero de éstos tiene un interés especial, ya que la incidencia de peces más pequeños es muy superior en las capturas realizadas cerca de la costa que en las de mar afuera, y se desea conocer si ésto se debe a la abundancia relativamente superior o a las vulnerabilidad relativamente mayor de los pequeños peces en las zonas costeras. Si el caso fuera el primero, se podría descubrir probablemente un movimiento de los peces mar afuera a medida que crecen. Sin embargo, no se ha descubierto tal movimiento, así que es probable que las diferencias en las capturas de peces pequeños en las zonas costeras y mar afuera se deban principalmente a diferencias en la vulnerabilidad. Se descubrió poca o ninguna tendencia en los peces a desplazarse este-oeste o norte-sur. El método de Jones indica que el movimiento no es aleatorio, pero no revela una tendencia pronunciada a orientarse direccionalmente.

Growth and age composition of northern bluefin tuna, Thunnus thynnus, caught in the Eastern Pacific Ocean, as estimated from length-frequency data, with comments on trans-Pacific migrations

ENGLISH: The spawning of Pacific northern bluefin tuna, Thunnus thynnus, takes place only in the western Pacific Ocean (WPO), but substantial numbers of the juveniles migrate to the eastern Pacific Ocean (EPO), where they remain for several months, or longer, and the.n return to the WPO. Lengthfrequency and tagging data show that many bluefin arrive in the EPO as 1-and 2-year olds, and remain there for one or two fishing seasons before returning to the WPO. The proportion of the fish which make the west-to-east migration varies among years. The numbers of 1-, 2-, 3-, 4, and >4 –year olds in the catches of the EPO are estimated for most years of the 1952-1991 period. SPANISH: EI desove del atun aleta azul del norte del Pacifico, Thunnus thynnus, ocurre solamente en el Océano Pacifico occidental (WPO), pero números substanciales de los juveniles migran al Océano Pacifico oriental (OPO), donde permanecen unos meses, 0 mas, antes de regresar al WPO. Datos de marcado y frecuencia de talla indican que muchos aletas azules llegan al OPO a 1 o 2 anos de edad, y permanecen alIi una 0 dos temporadas de pesca antes de regresar al WPO. La proporcion de los peces que migra del oeste al este varia entre anos. Se estima el numero de peces de 1, 2, 3, 4, Y>4 anos de edad en las capturas del OPO para la mayoria de los anos del periodo de 1952-1991. (PDF contains 40 pages.)

Observations on the distribution, daytime migrations and daily food intake rates of Chaoborus flavicans (Meigen) in the Goggausee [Translation from: Carinthia II 165(85), 184-190, 1975]

The Goggausee, in spite of its modest depth (Zmax = 12 metres), shows meromictic properties: autumn and spring circulation extend only to a depth of 8 metres. The water layers below about 10 metres are constantly oxygen-free, the critical zone with at least intermittent oxygen loss lies at a depth of between 6 and 10 metres. A limnological excursion in May 1974 offered an opportunity to investigate the daily vertical migration of the species Chaoborus flavicans with reference to its food supply of zooplankton as well as the chance to carry out some preliminary experiments on its rate of food intake. Among the studied features were the planktonic depth distribution of Chaoborus flavicans and the food intake of Chaoborus larvae under experimental conditions.

Biologie de Ethmalosa Fimbriata (Bowdich) en Côte d'Ivoire. 3 - Étude des Migrations en Lagune Ebrié

Spawning of bonga (Ethmalosa fimbriata Bowdich) takes place in polyhalin waters (Sppt. > 5ppt.). Migrations of young fish were studied by the mean of length data observed in different points of the lagoon from the artisanal fishery. Bonga remain 4 months in the hatchery (6 cm), before they expand in the whole lagoon until the age of 9/10 months. After this expansion phase, the fishes come back to the spawning fields (spawning length: 14/15 cm). Postspawning fishes leave the lagoon. Between birth and spawning, bonga are not affected by salinity changes, but reproduction occurs only in waters where salinity is higher than 5ppt.

Marquages de Penaeus duorarum notialis en Côte d'Ivoire. 2 - Migrations et mortalités

Petersen disc tag marking experiments confirm the influence of animal size and marking time on the recapture rate. Westward migrations occur, probably following the Ivorian undercurrent. Catchability coefficients have been evaluated for the Grand-Bassam fishing ground and tentatively extrapolated to the other fishing areas. The extrapolated non weighted coefficient for the entire fishing areas is q=0.00069/fishing day for an area of 390 miles. The instantaneous coefficient of residual mortality X taken as a first and possibly slightly overestimated value of M the natural mortality, has been estimated at 0.155/month, strongly corroborating Berry's results (1967). This value is however much smaller than that given by earlier authors. It is suggested that q could have a higher value during the very first weeks of exploitation at sea, when the juveniles are concentrated near the lagoon outlets.

Intermingling and seasonal migrations of Greenland halibut (Reinhardtius hippoglossoides) populations determined from tagging studies

A total of 7244 Greenland halibut (Reinhardtius hippoglossoides, Walbaum) were tagged in Greenland waters between 1986 and 1998 to increase information on stock delineations, to clarify migration routes, and to describe the seasonal movements of fjord populations. At present 517 recaptured Greenland halibut have been recorded. For Greenland halibut released in Davis Strait, Baffin Bay, and the fjords of southwestern and eastern Greenland, a substantial portion of recovered fish demonstrated migratory behavior, up to 2500 km, primarily to Denmark Strait between Greenland and Iceland. The recaptured fish provided evidence of intermingling between the population in Denmark Strait and the populations in Davis Strait and the southwest Greenland fjords. These observations support those of other studies that indicate that Greenland halibut inhabiting Davis Strait and the fjords of southwestern and eastern Greenland originate in the spawning grounds west of Iceland. The high mobility of offshore Greenland halibut within Baffin Bay and Davis Strait suggests that Greenland halibut migrate extensively between feeding and spawning areas. Greenland halibut in the fjords of northwestern Greenland appear to be resident in behavior and do not intermingle with offshore or more southerly inshore populations. A seasonal pattern in the recovery of these fish indicates that Greenland halibut aggregate in the inner part of fjords during the second half of the year (when inshore waters are not covered with ice).

PICES-GLOBEC International Program on Climate Change and Carrying Capacity: Report of the 1999 MONITOR and REX Workshops, and the 2000 MODEL Workshop on Lower Trophic Level Modelling

Table of Contents [pdf, 0.11 Mb] Executive Summary [pdf, 0.07 Mb] MODEL Task Team Workshop Report Final Report of the International Workshop to Develop a Prototype Lower Trophic Level Ecosystem Model for Comparison of Different Marine Ecosystems in the North Pacific [pdf, 11.64 Mb] Report of the 1999 MONITOR Task Team Workshop [pdf, 0.32 Mb] Report of the 1999 REX Task Team Workshop Herring and Euphausiid population dynamics Douglas E. Hay and Bruce McCarter Spatial, temporal and life-stage variation in herring diets in British Columbia [pdf, 0.10 Mb] Augustus J. Paul and J. M. Paul Over winter changes in herring from Prince William Sound, Alaska [pdf, 0.08 Mb] N. G. Chupisheva Qualitative texture characteristic of herring (Clupea pallasi pallasi) pre-larvae developed from the natural and artificial spawning-grounds in Severnaya Bay (Peter the Great Bay) [pdf, 0.07 Mb] Gordon A. McFarlane, Richard J. Beamish and Jake SchweigertPacific herring: Common factors have opposite impacts in adjacent ecosystems [pdf, 0.15 Mb] Tokimasa Kobayashi, Keizou Yabuki, Masayoshi Sasaki and Jun-Ichi Kodama Long-term fluctuation of the catch of Pacific herring in Northern Japan [pdf, 0.39 Mb] Jacqueline M. O’Connell Holocene fish remains from Saanich Inlet, British Columbia, Canada [pdf, 0.40 Mb] Elsa R. Ivshina and Irina Y. Bragina On relationship between crustacean zooplankton (Euphausiidae and Copepods) and Sakhalin-Hokkaido herring (Tatar Strait, Sea of Japan) [pdf, 0.14 Mb] Stein Kaartvbeedt Fish predation on krill and krill antipredator behaviour [pdf, 0.08 Mb] Nikolai I. Naumenko Euphausiids and western Bering Sea herring feeding [pdf, 0.07 Mb] David M. Checkley, Jr. Interactions Between Fish and Euphausiids and Potential Relations to Climate and Recruitment [pdf, 0.08 Mb] Vladimir I. Radchenko and Elena P. Dulepova Shall we expect the Korf-Karaginsky herring migrations into the offshore western Bering Sea? [pdf, 0.75 Mb] Young Shil Kang Euphausiids in the Korean waters and its relationship with major fish resources [pdf, 0.29 Mb] William T. Peterson, Leah Feinberg and Julie Keister Ecological Zonation of euphausiids off central Oregon [pdf, 0.11 Mb] Scott M. Rumsey Environmentally forced variability in larval development and stage-structure: Implications for the recruitment of Euphausia pacifica (Hansen) in the Southern California Bight [pdf, 3.26 Mb] Scott M. Rumsey Inverse modelling of developmental parameters in Euphausia pacifica: The relative importance of spawning history and environmental forcing to larval stage-frequency distributions [pdf, 98.79 Mb] Michio J. Kishi, Hitoshi Motono & Kohji Asahi An ecosystem model with zooplankton vertical migration focused on Oyashio region [pdf, 33.32 Mb] PICES-GLOBEC Implementation Panel on Climate Change and Carrying Capacity Program Executive Committee and Task Team List [pdf, 0.05 Mb] (Document pdf contains 142 pages)

Blood lactate in yellowfin tuna, Neothunnus macropterus, and skipjack, Katsuwonus pelamis, following capture and tagging

ENGLISH: The staff of the Inter-American Tropical Tuna Commission for several years has been investigating the life history, population structure, behavior and ecology of the yellowfin tuna, Neothunnus macropterus, and the skipjack, Katsuwonus pelamis, in the Eastern Tropical Pacific Ocean. The tagging and subsequent recovery of these tropical tunas, to provide information on population structure, migrations, mortality rates and growth rates, are important aspects of these investigations. Broadhead (1959) and Schaefer, Chatwin and Broadhead (1961) emphasize the many difficulties involved in tagging these extremely active yet delicate fish and give considerable evidence to suggest that tagging mortality is high, perhaps as great as 60 to 80 per cent. The latter authors suggest that the rather high mortality at tagging is related to the effects of hyperactivity brought about by the tagging operation. SPANISH: El personal de la Comisión Interamericana del Atún Tropical ha estado investigando durante varios años la historia natural, la estructura de la población, los hábitos y la ecología del atún aleta amarilla, Neothunnus macropterus, y del barrilete, Katsuwonus pelamis, en el Océano Pacífico Oriental Tropical. La marcación y el subsiguiente recobro de estos atunes tropicales, lo que da información sobre la estructura de la población, los movimientos migratorios y las tasas de crecimiento y de mortalidad, son importantes aspectos de estas investigaciones. Broadhead (1959) y Schaefer, Chatwin y Broadhead (1961) destacan las muchas dificultades que hay para marcar estos peces activos en extremo pero delicados, y proporcionan considerable evidencia que sugiere que la mortalidad por la marcación es bastante alta, siendo quizás de 60 a 80 por ciento. Los autores citados sugieren que esta elevada mortalidad por la marcación está relacionada con los efectos de la hiperactividad producida por la operación de marcación.

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 atún aleta amarilla y el barrilete se encuentran en cantidades comerciales en el Océano Pacífico 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 Comisión Interamericana del Atún Tropical ha estado dedicada durante varios años a la investigación de la biología, ecología y dinámica de las poblaciones de los stocks de las indicadas especies que mantienen la pesquería comercial, a fin de elucidar los efectos de ésta y de los factores independientes de la explotación sobre la abundancia y hábitos de estos peces, para obtener una base científica que permita una administración racional de la pesquería. Un aspecto importante de esta investigación es el estudio de los movimientos migratorios de estas especies en el Pacífico Oriental, y la determinación de que si cada una constituye una sola población o está compuesta de varias subpoblaciones. Un medio directo de abordar estos problemas es el de la marcación, y subsecuente recuperación, de especímenes en la región de la pesquería comercial. Esto también proporciona una información directa sobre la tasa de crecimiento, por la comparación de los tamaños de los especímenes al ser marcados y recuperados más tarde y puede proveer la base para estimar las tasas de mortalidad. Estos son dos de los elementos importantes de las estadísticas vitales de las poblaciones de atún.

Estimation of year class abundance and mortality of yellowfin tuna in the Eastern Tropical Pacific

ENGLISH: Age composition of catch, and growth rate, of yellowfin tuna have been estimated by Hennemuth (1961a) and Davidoff (1963). The relative abundance and instantaneous total mortality rate of yellowfin tuna during 1954-1959 have been estimated by Hennenmuth (1961b). It is now possible to extend this work, because more data are available; these include data for 1951-1954, which were previously not available, and data for 1960-1962, which were collected subsequent to Hennemuth's (1961b) publication. In that publication, Hennemuth estimated the total instantaneous mortality rate (Z) during the entire time period a year class is present in the fishery following full recruitment. However, this method may lead to biased estimates of abundance, and hence mortality rates, because of both seasonal migrations into or out of specific fishing areas and possible seasonal differences in availability or vulnerability of the fish to the fishing gear. Schaefer, Chatwin and Broadhead (1961) and Joseph etl al. (1964) have indicated that seasonal migrations of yellowfin occur. A method of estimating mortality rates which is not biased by seasonal movements would be of value in computations of population dynamics. The method of analysis outlined and used in the present paper may obviate this bias by comparing the abundance of an individual yellowfin year class, following its period of maximum abundance, in an individual area during a specific quarter of the year with its abundance in the same area one year later. The method was suggested by Gulland (1955) and used by Chapman, Holt and Allen (1963) in assessing Antarctic whale stocks. This method, and the results of its use with data for yellowfin caught in the eastern tropical Pacific from 1951-1962 are described in this paper. SPANISH: La composición de edad de la captura, y la tasa de crecimiento del atún aleta amarilla, han sido estimadas por Hennemuth (1961a) y Davidoff (1963). Hennemuth (1961b), estimó la abundancia relativa y la tasa de mortalidad total instantánea del atún aleta amarilla durante 1954-1959. Se puede ampliar ahora, este trabajo, porque se dispone de más datos; éstos incluyen datos de 1951 1954, de los cuales no se disponía antes, y datos de 1960-1962 que fueron recolectados después de la publicación de Hennemuth (1961b). En esa obra, Hennemuth estimó la tasa de mortalidad total instantánea (Z) durante todo el período de tiempo en el cual una clase anual está presente en la pesquería, consecutiva al reclutamiento total. Sin embargo, este método puede conducir a estimaciones con bias (inclinación viciada) de abundancia, y de aquí las tasas de mortalidad, debidas tanto a migraciones estacionales dentro o fuera de las áreas determinadas de pesca, como a posibles diferencias estacionales en la disponibilidad y vulnerabilidad de los peces al equipo de pesca. Schaefer, Chatwin y Broadhead (1961) y Joseph et al. (1964) han indicado que ocurren migraciones estacionales de atún aleta amarilla. Un método para estimar las tasas de mortalidad el cual no tuviera bias debido a los movimientos estacionales, sería de valor en los cómputos de la dinámica de las poblaciones. El método de análisis delineado y usado en el presente estudio puede evitar este bias al comparar la abundancia de una clase anual individual de atún aleta amarilla, subsecuente a su período de abundancia máxima en un área individual, durante un trimestre específico del año, con su abundancia en la misma área un año más tarde. Este método fue sugerido por Gulland (1955) y empleado por Chapman, Holt y Allen (1963) en la declaración de los stocks de la ballena antártica. Este método y los resultados de su uso, en combinación con los datos del atún aleta amarilla capturado en el Pacífico oriental tropical desde 1951-1962, son descritos en este estudio.