A simple approach for the estimation of food consumption from growth rates at different environmental conditions and its application to juvenile cod (Gadus morhua L.) of a fjordic sea loch on the west coast of Scotland

Abstract Growth and condition of fish are functions of available food and environmental conditions. This led to the idea of using fish as a “consumption sensor” for the measurement of food intake over a defined period of time. A bio-physical model for the estimation of food consumption was developed based on the von Bertalanffy model. Whereas some of the input variables of the model, the initial and final lengths and masses of a fish and the temperature within the time period considered can easily be measured, internal characteristics of the species have to be determined indirectly. Three internal parameters are used in the model: the maintenance consumption at 0°C, the temperature dependence of this consumption and the food efficiency, the percentage of the ingested food utilized. Estimates of the parameters for a given species can be determined by feeding experiments. Here, data from published feeding experiments on juvenile cod, Gadus morhua L., were used to validate the model. The average of the relative error for the food intake predicted by the model for individual fish was about 24 %, indicating that fish used the food with different efficiencies. However, grouping the fish according to size classes and temperature lowered the relative error of the predicted food intake for the group to typically 5 %. For a group containing all fish of the feeding experiment the relative prediction error was about 2 %. Zusammenfassung Wachstum und Kondition der Fische sind von der verfügbaren Nahrung und von Umweltbedingungen abhängig. Dies führte zur Idee, Fisch als „Konsum-Sensor“ für die Messung der Nahrungsaufnahme über einen definierten Zeitraum zu verwenden. Auf Grundlage des von Bertalanffy-Modells wurde ein bio-physikalisches Modell zur Schätzung der Futteraufnahme entwickelt. Während einige der Eingangsgrößen des Modells leicht gemessen werden können (Anfangs- und Endlänge und -körpermasse der Fische und die Temperatur innerhalb des betrachteten Zeitraum), können interne Parameter der betrachteten Art nur indirekt bestimmt werden. Drei interne Parameter werden in dem Modell verwendet: Die Erhaltungskonsumtion bei 0° C, die Temperaturabhängigkeit dieser Rate und der Wirkungsgrad der Nahrung (der Anteil der Nahrung ,der aufgenommen und verwendet und nicht ungenutzt wieder ausgeschieden wird). Die Modellparameter für eine bestimmte Art können durch Fütterungsversuche bestimmt werden. Um das Modell zu validieren wurden Daten aus veröffentlichten Fütterungsversuchen mit juvenilen Kabeljau (Gadus morhua L.) verwendet. Modell und Wirklichkeit weichen in der Regel voneinander ab. Der durchschnittliche relative Fehler der durch das Modell vorhergesagten Nahrungsaufnahme betrug für Einzelfische etwa 24%, was darauf hinweist, dass einzelne Fisch die Nahrung mit unterschiedlichen Wirkungsgraden verwerten. Allerdings senkte die Gruppierung der Fische nach Größenklassen und Temperatur den relativen Vorhersagefehler für die Nahrungsaufnahme der Gruppe auf etwa 5%. Für alle Fische im Fütterungsversuch ist der relative Vorhersagefehler etwa 2%.

Observations on the behaviour of Polyphemus pediculus and functions of its extremities in the process of feeding. [Translation of: Materialy po biologii i gidrologii Volzhskikh vodokhranilishch, pp. 13-16. Moscow, 1965]

The author summarises observations on the behaviour of Polyphemus pediculus and functions of its extremities in the process of feeding. The crustacean Polyphemus pediculus seizes its prey, kills it and pulverises its food with the help of its extremities. Therefore for a study of its feeding method was necessary not only to have been acquainted in detail with the structure of its extremities, but also to have observed their interaction for the accomplishment of the stated functions.

Organization, functions, and achievements of the Inter-American Tropical Tuna Commission

ENGLISH: The Inter-American Tropical Tuna Commission (IATTC) operates under the authority and direction of a Convention originally entered into by the governments of Costa Rica and the United states. The Convention, which came into force in 1950, is open to the adherence by other governments whose nationals participate in the fisheries for tropical tunas in the eastern Pacific Ocean. The member nations of the Commission now are France. Japan, Nicaragua. Panama, and the United States. This report is a description of the organization, functions. and achievements of the Commission. It has been prepared to provide in a convenient format answers to requests for information concerning the Commission. It replaces similar, earlier reports (Carroz, 1965; Spec. Rep., 1), which are now largely outdated. SPANISH: La Comisión Interamericana del Atún Tropical (CIAT) funciona bajo la autoridad y dirección de un Convenio firmado originalmente por los gobiernos de Costa Rica y los Estados Unidos de America. El Convenio, Que entre en vigencia en 1950, se encuentra libre para Que otros gobiernos cuyos ciudadanos participan en la pesca de los atunes tropicales en el Océano Pacifico oriental se afilien a 61. Las naciones actuales que son miembros de la Comisión son: Francia, Japón, Nicaragua, Panamá y los Estados Unidos. Este informe es una descripci6n de la organización, funciones y resultados de la Comisión. Se ha preparado para suministrar en forma conveniente, informaci6n sobre la Comisión. Este informe renueva otros anteriores similares (Carroz, 1965; CIAT, Inf. Esp., 1) que en su mayor parte determinados.

Rapport sur le fonctionnement du Service Océanographique des Pêches de L'Indochine pendant l'année 1926-1927

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1926-1927.

Rapport sur le fonctionnement du Service Océanographique des Pêches de l'Indochine pendant l'année 1927-1928

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1927-1928.

Rapport sur le fonctionnement du Service Océanographique des Pêches de l'Indochine pendant l'année 1928-1929

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1928-1929.

Rapport sur le fonctionnement du l'Institut Océanographique de l'Indochine pendant l'année 1929-1930

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1929-1930.

Rapport sur le fonctionnement du l'Institut Océanographique de l'Indochine pendant l'année 1930-1931

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1930-1931.

Rapport sur le fonctionnement du l'Institut Océanographique de l'Indochine pendant l'année 1931-1932

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1931-1932.

Rapport sur le fonctionnement de l'Institut Océanographique de l'Indochine pendant l'année 1932-1933

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1932-1933.

Rapport sur le fonctionnement du l'Institut Océanographique de l'Indochine pendant l'année 1933-1934

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1933-1934.

Rapport sur le fonctionnement de l'Institut Océanographique de l'Indochine pendant l'année 1934-1935

The present note deals with the functions and activities done by the Institute of oceanography of Indochina during 1934-1935.

Rapport sur le fonctionnement de l'Institut Océanographique de l'Indochine pendant l'année 1935-1936

The present note deals with the functions and activities carried out by the Institute of oceanography of Indochina during 1935-1936

Rapport sur le fonctionnement de l'Institut Océanographique de l'Indochine pendant l'année 1936-1937

The present note deals with the functions and activities carried out by the Institute of oceanography of Indochina during 1936-1937

Rapport sur le fonctionnement de l'Institut Océanographique de l'Indochine pendant l'année 1937-1938

The present note deals with the functions and activities carried out by the Institute of oceanography of Indochina during 1937-1938