The Effects of Salinity, Temperature, and Food on the Growth and Reproductive Output of Polydora nuchalis Woodick, 1953

Polydora nuchalis Woodwick, 1953 (Polychaeta: Spionidae) is a protandric hermaphrodite commonly inhabiting intertidal mud flats in southern California. The species exhibits lecithotrophic larval development and adelphophagia. Reproduction of P. nuchalis was monitored for a year at four sites: Catalina Harbor, San Gabriel River, Huntington Harbour, and Malibu Lagoon. Females deposited from 11 to 31 egg capsules in their tubes, with up to 230 eggs per capsule. An average of 3% of the eggs developed into larvae: the remaining were nurse eggs serving as food for the developing larvae. Reproductive output was quantified by determining the number and size of larvae and nurse eggs for individual capsules. Significant differences among the four populations were found for all the quantified variables. In addition, two size classes of nurse eggs were found to exist in capsules from all of the sites. Egg capsules were found throughout the year at San Gabriel River, but none were found during the winter months at the remaining three sites. Size/frequency data for juveniles and adults of the Catalina Harbor population indicate an annual cycle of recruitment. The laboratory experiment consisted of a 3 x 3 x 2 £actor1al design with replication testing the effects of temperature, salinity, and food supply on growth and reproduction of P. nuchalis. Increasing temperature resulted in significantly increased survivorship, growth rates, and percentage reproduction. It also produced a significant decrease in the size of the nurse eggs and the volume of food per larva. The number of egg capsules was maximum at the intermediate temperature. Increasing the salinity resulted in significant increases in survivorship and Class I nurse egg size. Increaaing food availability produced a significant increase in the percentage of worms reproducing. The interactive effect of salinity and £ood level produced significant changes in the number of larvae per capsule and the number of nurse eggs per capsule. However, the number of nurse eggs per larva did not differ significantly among the experimental treatment groups. (PDF contains 129 pages)

A.L.O.A. (Asociación Limnológica y Oceanográfica Argentina ) Resumen de las Comunicaciones Presentadas en la Reunión del 11 de setiembre de 1953

Prosiguiendo con la política de rescatar documentos que, por diferentes motivos, se han extraviado con el paso del tiempo, el Programa para el estudio y uso sustentable de la biota austral (ProBiota) reedita el primer y único boletín de la Asociación Limnológica y Oceanográfica Argentina (ALOA). Esta asociación pretendía convocar a los hidrobiólogos argentinos, pero interrumpió su camino a poco de iniciado en el año 1953. Los motivos de ese hecho los desconozco; aunque personalmente creo que, entre otras cosas, debe haber influido el quiebre institucional de 1955 cuando se profundizaron nuevamente las heridas en nuestra sociedad. No deja de ser paradójico que hoy, a casi cincuenta años de este suceso, la Asociación Argentina de Limnología (AAL) se encuentre en una situación similar luego de veinte años de trayectoria que se cumplirían en el mes de marzo del próximo año. Hasta 1998, fecha de su último congreso, tuvo un gran impulso generando importantes eventos nacionales e internacionales. Sin embargo, a partir de allí fue decayendo con rapidez y hoy se enfrenta a su inminente disolución. A mi entender, la reversión de este hecho sólo podría lograrse sobre la base del sacrificio personal y del conjunto, solidaridad y, sobre todo, respeto a la memoria de todos aquellos que construyeron las bases de la limnología nacional.

Motor vessel "N. B. Scofield" cruise one of 1953. Cruise Report 53-S-1

(PDF contains 7 pages.)

Tunas and tuna fisheries of the World: an annotated bibliography, 1930-1953

This bibliography attempts to list, with descriptive annotations and a subject index, important literature published between 1930 and 1953 dealing with the tunas and their fisheries in all parts of the world. It is thus a continuation of Corwin's (1930) work, which extended with similar scope through 1929, and an extension of Shimada's (1951), which was limited to the biology of Pacific tunas. The tunas with which it deals are those fishes customarily so-called in commercial parlance and usually classified in the genera Thunnus, Neothunnus, Parathunnus, Germo, Katsuwonus, Euthynnus and Auxis and their various synonyms. All aspects of the biology of the tunas are dealt with, as are descriptions and histories of all types of tuna fisheries, commercial and exploratory tuna fishing methods and results, fishing gear, catch statistics, and fishery management, but processing technology, economics and marketing, folklore, and purely literary references have been excluded.

Cruise 2 of the N. B. Scofield for 1953. Cruise Report 53-S-2

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Cruise 3 of the N. B. Scofield for 1953. Cruise Report 53-S-3

(PDF contains 3 pages.)

Cruise 4 of the N. B. Scofield for 1953. Cruise Report 53-S-4

(PDF contains 3 pages.)

Cruise 5 of the N. B. Scofield for 1953. Cruise Report 53-S-5

(PDF contains 3 pages.)

Cruise 6 of the N. B. Scofield for 1953. Cruise Report 53-S-6

(PDF contains 2 pages.)

Cruise 7 of the N. B. Scofield for 1953. Cruise Report 53-S-7

(PDF contains 2 pages.)

Report of the Inter-American Tropical Tuna Commission for the year 1953

ENGLISH: The Inter-American Tropical Tuna Commission was established in 1950 by a Convention between Costa Rica and the United States. The Convention provides for the subsequent adherence of other nations interested in the tuna fishery of the tropical Eastern Pacific Ocean. Panama adhered to the Convention in September 1953. The Commission has the duties of collecting and interpreting all necessary factual information respecting the tunas and tuna-bait fishes in order to facilitate maintaining the populations thereof at levels permitting maximum sustained yields, and of making recommendations to the member governments for joint action toward this objective. The Commission commenced its investigations in 1951. The year 1953 is the third year of scientific study. During the year investigations along several lines were continued and further developed. SPANISH: La Comisión Interamericano del Atún Tropical fué establecida en 1950 en virtud de una Convención entre Costa Rica y los Estados Unidos. La Convención abre la puerta para que otras naciones interesadas en las pesquerías de atún en aguas tropicales del Pacífico Oriental, puedan adherirse posteriormente. Panamá se adhirió al Tratado en Septiembre de 1953. La Comisión tiene como deberes recolectar e interpretar todos los informes necesarios respecto de las especies de atún y de los peces de carnada que sirven para pescarlas¡ a fin de facilitar el mantenimiento de las respectivas poblaciones a niveles que permitan un rendimiento máximo permanente; y hacer recomendaciones a los gobiernos miembros para que actúen conjuntamente en pro de los indicados objetivos. Nuestro organismo comenzó sus investigaciones en 1951. El año 1953 es el tercero de estudios científicos. Durante dicho año se continuaron investigaciones en diversas líneas y se prosiguió su desarrollo. (PDF contains 87 pages.)

The state of the benthos in the Rybinsk reservoir, 1953-55. [Translation of the abstract from: Trudy biol. Sta. Borok 3, 195-213, 1958]

This abstract summarises the 1953-1955 surveys of the distribution of benthos in the Rybinsk Reservoirs. It includes the mean biomass of benthos.

Concentrations of major ions in 182 tarns in the English Lake District (1953-1978) [Dataset]

This dataset provides raw data of chemical analyses made during studies on seasonal variations of 182 tarns in the English Lake District, Cumbria. Measurements of sodium, calcium, potassium, magnesium, pH, chloride ions, alkalinity, sulphite, strong acids and nitrate were taken between 1953 and 1978.

Le régime alimentaire de Dentex angolensis, Poll et Maul, 1953 (Sparidae)

The food of Dentex angolensis, studied from 386 stomachs, consists essentially of small epibenthic crustaceans and, with less importance, of fishes. A systematic list with abundance and occurrence is given here. It is noted that the composition of the stomach content can differ with depth and season.