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 hábitos gregarios de los atunes aleta amarilla y barrilete pueden ser investigados a base de los registros de bitácora 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 propósitos hay que suponer que las operaciones se efectúan, en cada caso, en un cardumen independiente. El estudio de los tamaños de los cardúmenes o manchas, a base de estos datos, requiere una suposición adicional: que el cardumen entero es capturado o, en su defecto, que en cada operación con la red se pesca una fracción constante de la mancha objeto de la pesca. En el presente artículo damos cuenta de los resultados de dichas investigaciones basadas en los registros de bitácora que lleva la flota de embarcaciones que utilizan redes de encierre. (PDF contains 47 pages.)

21. Sitzung des FAO/WHO Codex Alimentarius Komitees für Fische und Fischerzeugnisse in Bergen/Norwegen

Auf der 21. Sitzung des Fischkomitees wurden die in den letzten 4 Jahren mit dem Ziel der Vereinfachung überarbeiteten Standardentwürfe für Erzeugnisse abschließend beraten und an die Kommission zur Annahme überwiesen. Die verschiedenen Codes of Practice werden am Beispiel des von einer Arbeitsgruppe revidierten und um HACCP-Prinzipien erweiterten Codes für tiefgefrorene Fischfilets von 7 neu eingesetzten Arbeitsgruppen überarbeitet. Eine Regelung über Richtwerte für Quecksilber in Fischen ist in Aussicht.

Maryland commercial fisheries statistics, 1946-1950

This bulletin is the second of a series begun in 1948, designed to present detailed records of the commercial fish catch of the state. The statistics set forth were derived from records obtained only from licensed commercial fishermen and contain no data pertaining to small unlicensed units of fishing gear, or to the sports fishery.

The history and research results of the East African Freshwater Fisheries Research Organization from 1946 - 1966.

Continuous research on the freshwater fisheries industry in East Africa, in common with most other African countries, did not commence until the end of the Second World War in 1945. Before the war some work on the fishes and hydrobiology of the lakes of East Africa had been undertaken by a series of scientific expeditions, which were sent out from Europe, between the years 1896 and 1939. These expeditions usually lasted for only a few months, and the collected data were published by young graduates and undergraduates, including such people as Mr. L. C. Beadle, (lately Professor Beadle of Makerere), Mr. V. E. Fuchs (now Sir Vivian Fuchs) and Mr. E. B. Worthington of Gonville and Caius College,Cambridge. Later. Dr. Worthington became Scientific Secretary to the Scientific Council for Africa, Scientific Secretary to the East African High Commission, and played a very large part in the furtherance of fisheries research and management in East Africa.

Temas de Ciencias Naturales.

El 29 de abril del año próximo pasado se cumplieron veinte años del fallecimiento de Raúl Adolfo Ringuelet, quién fuera uno de los científicos más destacados que han dado las ciencias naturales de la Argentina. Salvo contadas excepciones, no hubo recordatorios sobre este acontecimiento, pero el Dr. Ringuelet es uno de los casos que no necesita de la magnanimidad y el tiempo de los mortales para tenerlo presente, ya que la vigencia y el peso de su obra, hacen cumplir con aquello de que “mientras el recuerdo permanece, la muerte no existe”. El Programa para el Estudio y Uso Sustentable de la Biota Austral (ProBiota) quiere recordarlo reproduciendo la publicación de una serie de conferencias dictadas en su juventud, durante 1943 y 1944, en LS 11 Radio Provincia de Buenos Aires y que fueron publicadas en 1946 bajo el título de “Temas de Ciencias Naturales”. En ese año, Raúl A. Ringuelet contaba con treinta dos años y el mundo se encontraba en su mayor parte lacerado y bajo ruinas por la conducta recurrente de la “especie hipócrita” que, en nombre de las ideologías y la paz universal, había concretado la matanza de varios millones de personas. En nuestro país se asistía al nacimiento de un nuevo movimiento histórico y el comienzo de profundos desencuentros en nuestra sociedad, los cuales, lamentablemente, aún no han terminado. En esta década la ciencia argentina sería destacada con el Premio Nóbel a través del Dr. Bernardo Houssay y en las ciencias naturales se habían publicado, entre otras obras, los rasgos principales de la Fitogeografía argentina de J. Frenguelli, la Zoogeografía de Cabrera y Yepes, la última entrega del catalógo sistemático de las aves de Argentina de Steullet y Deautier, y el estudio de la Selva Marginal de Punta Lara de A. L. Cabrera (hijo) y G. Dawson. La lectura de estas conferencias, un total de diez, nos muestra, ya entonces, el espíritu rico, inquieto y polifacético de Raúl A. Ringuelet, el cuál lo distinguiría pocos años después. En algunas de ellas realiza la reseña de la vida y obra de diferentes científicos y naturalistas de nuestro país; en las restantes, expresa ingeniosamente conceptos precursores sobre biodiversidad, conservación y manejo de los recursos naturales y su transferencia a los diferentes niveles de la sociedad. Finalmente, desde ProBiota consideramos que la trascripción de este tipo de documentos constituye un aporte para aquellos interesados en la historia de las ciencias naturales y, asimismo, una contribución para que nuestras jóvenes generaciones de biólogos y naturalistas posean una noción más clara de quienes marcaron rumbos e hicieron escuela en nuestra disciplina con un genuino sentido nacional.

Nota acerca de los nombres vernáculos de peces en el Paraná medio.

Lista complementaria del trabajo de Pozzi sobre Sistemática y distribución de los peces de agua dulce de la República Argentina, donde se incluyen sólo los nombres faltantes o los extensivos a otras especies o los que tengan distinta significación.

A history of the Connecticut River and its fisheries

(PDF contains 15 pages)

Population characteristics of gulf menhaden, Brevoortia patronus

The status of the Gulf menhaden, Brevoortia patronus, fishery was assessed with purse-seine landings data from 1946 to 1997 and port sampling data from 1964 to 1997. These data were analyzed to determine growth rates, biological reference points for fi shing mortality from yield per recruit and maximum spawning potential analyses, spawner-recruit relationships, and maximum sustainable yield (MSY). The separable virtual population approach was used for the period 1976–97 (augmented by earlier analyses for 1964–75) to obtain point estimates of stock size, recruits to age 1, spawning stock size, and fishing mortality rates. Exploitation rates for age-1 fi sh ranged between 11% and 45%, for age-2 fi sh between 32% and 72%, and for age-3 fi sh between 32% and 76%. Biological reference points from yield per recruit (F0.1: 1.5–2.5/yr) and spawning potential ratio (F20: 1.3–1.9/yr and F30: 0.8–1.2/yr) were obtained for comparison with recent estimates of F (0.6–0.8/yr). Recent spawning stock estimates (as biomass or eggs) are above the long-term average, while recent recruits to age 1 are comparable to the long-term average. Parameters from Ricker-type spawner-recruit relations were estimated, although considerable unexplained variability remained. Recent survival to age-1 recruitment has generally been below that expected based on the Ricker spawner-recruit relation. Estimates of long-term MSY from PRODFIT and ASPIC estimation of production model ranged between 717,000 t and 753,000 t, respectively. Declines in landings between 1988 and 1992 raised concerns about the status of the Gulf menhaden stock. Landings have fl uctuated without trend since 1992, averaging about 571,000 t. However, Gulf menhaden are short lived and highly fecund. Thus, variation in recruitment to age 1, largely mediated by environmental conditions, infl uences fi shing success over the next two years (as age-1 and age-2 fi sh). Comparisons of recent estimates of fi shing mortality to biological reference points do not suggest overfishing. (PDF file contains 22 pages.)

Population Characteristics of Gulf Menhaden, Brevoortia patronus

The status of the gulf menhaden, Brevoortia patronus, fishery was assessed with purseseine landing data from 1946 to 1992 and port sampling data from 1964 to 1992. These data were analyzed to determine growth rates, biological reference points for fishing mortality from yield per recruit and maximum spawning potential analyses, spawner-recruit relationships, and maximum sustainable yield (MSY). Virtual population approaches were used to obtain point estimates of stock size, recruits to age I, spawning stock size, and fishing mortality rates. Exploitation rates ranged between 14% and 45% for age-1 fish, between 30% and 72% for age-2 fish, and between 36% and 71% for age-3 fish. Biological reference points from yield per recruit (FO. I: 0.7-0.9 yr-1) and maximum spawning potential (F20: 1.62.9 yr-l and F30: 1.0-2.1 yr-1) were obtained for comparison with recent estimates of F (0.4-0.8 yr-l). Parameters from Ricker-type spawner-recruit relations were estimated, although considerable unexplained variability remained. Estimates of long-term MSY from fits of the generalized production model ranged between 664,000 metric tons (t) and 897,000 t. Declines in landings since 1988 have raised concerns about the status of the gulf menhaden stock. However, gulf menhaden are short lived and highly fecund. Thus, variation in recruitment to age 1 largely mediated by environmental conditions influences fishing success over the next two years (as age-1 and age-2 fish). Comparisons of recent estimates of fishing mortality to biological reference points do not suggest overfishing. (PDF file contains 26 pages.)