Report of the Inter-American Tropical Tuna Commission for the years 1950 and 1951

ENGLISH: The Convention between the United States of America and the Republic of Costa Rica for the establishment of an Inter-American Tropical Tuna Commission was signed May 31, 1949. Ratifications were exchanged on March 3, 1950, after arrival at understandings respecting the interpretation of certain provisions. The text of the Convention is appended to this report. Also appended are the enabling legislation passed by the United States Congress, giving effect to the Convention, and the Decree ratifying the Convention adopted by the Republic of Costa Rica. The most important provisions of the Convention may be summarized here, as the basis for the policy and actions of the Commission. SPANISH: La Convención entre los Estados Unidos de América y la República de Costa Rica para el establecimiento de la, Comisión Interamericana del Atún Tropical fué suscrita el 31 de Mayo de 1949. El cambio de ratificaciones, después de haber llegado a un entendimiento respecto de la interpretación de ciertas cláusulas, se efectuó el 3 de Marzo de 1950. El texto de la Convención se agrega a este informe. También se agrega la legislación correspondiente, emitida por el Congreso de los Estados Unidos para dar efectividad a la Convención, y el Decreto de Ratificación del Convenio promulgado por la República de Costa Rica. Los aspectos más importantes de la Convención se sintetizan aquí por constituir las bases que regulan la política y los actos de la Comisión, creada en virtud de aquélla. (PDF contains 58 pages.)

Algae from the inland ice of Greenland. [Translation from: Kongl.Vetenskaps-Akademiens Forhandlingar 1871(2) 293-296, 1871.]

On the large inland ice cover of Greenland, where the temperature even during the short summer, falls below freezing some time during the daily 24 hours, it is still possible to find organic life. The author found in melted ice water several species of algae on his ”walk” in the latter part of July 1870. The article describes the finds and tries to identify the algae to family level.

Quantitative data on the feeding of Cyclops strenuus Fischer and Cyclops viridis Jurine. [Translation from: Trudy saratov.Otd.vses.nauchno-issled.Inst.ozer.rech.ryb.Khoz. 1, 163-176, 1951.]

Cyclopids, exactly in the same way as daphnids, significant component in the nutrition of plankton-f and the young of the majority of fishes. It is established that the food spectrum of cyclopids is extremely broad: daphnids, planarians, Copepodite stages of copepods (cannibalism), rotifers, protists, bacteria, phytoplankton and so on. It is clear that the problem of studying these or other components of feeding in the general food spectrum can be definitely resolved only after obtaining exact quantitative data on the feeding of cyclopids. This article attempts to fill the gap in the study of the quantitative side of the feeding of cyclopias; in it is investigated the size of the 24-hour ration of cyclopids feeding on protists, the dependence of the ration on some factors of the external medium, and the difference of 24-hour consumption per unit weight of tody with two species of cyclopids (Cyclops strenuus and Cyclops viridis).

The periodicity in the consumption of oxygen in Asellus aquaticus [Translation from: Vestnik ceskoslovenske zoologicke Spolecnosti, 15, 1, 89-97, 1951]

The consumption of oxygen in Asellus aquaticus was measured to find if there existed a periodicity in the consumption of oxygen and how this showed itself during the course of the day, year and in various experimental conditions. From the figures obtained comparative values were calculated and from these curves were plotted of the changes in the consumption of oxygen during the day and year.

Extent and biomass of the aquatic chariphytes and mosses in Lake Sevan [Translation from: Rasprostranenie i biomassa kharovykh vodoroslei i mkha v os. Sevan, 1951]

This study focusses on the plants in the open parts of the lake - mostly aquatic charophytes and mosses, in what are called in Lake Sevan (Armenia), the ”zones of chara and moss”. Distribution and other ecological conditions are reviewed. Quantity of chara in the littoral zone of lake Sevan is provided

Factors influencing the start of development in Daphnia pulex winter eggs [Translation from: Biological Reviews Vol. 13, 24-26, 1951]

The winter eggs of Daphnia pulex, after passing safely through the winter , develop and hatch in the spring, multiplying by themselves, while some males emerging among them with the changes in environment produce fertile eggs, which are universally known as winter eggs . This study researches the factors governing the development of winter eggs through experiments.

New Weir and Fish Pass Whitendale in August 1951

Two men working in a weir and fish pass at Whitendale, North West England, UK. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

New Weir and Fish Pass Whitendale in August 1951

Two men working in a weir and fish pass at Whitendale, North West England, UK. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Fish Trap at Gastang weir in the River Wyre in August 1951

Fish trap at Garstang weir in the River Wyre, North West of England, UK. This photo shows pollution in River Lune in July 1949. This photo is part of a Photo Album that includes pictures from 1935 to 1954.

Maryland commercial fisheries statistics, 1951-1952

This bulletin is the third of a series begun in 1948, presenting detailed data on the commercial fin-fishery of Maryland. A full description of the techniques of collection and tabulation were included in the first bulletin [Publication 69], and inasmuch as identical procedures have been employed throughout the program, further mention of methods is not made. As in past years, records were received on a voluntary basis from approximately 94% of all licensed fishermen. Most of the records were submitted in the form of weekly or monthly summaries. 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 sport fishery.

Reconstructed drought history, north-central Great Basin, 1600-1982 [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Tree-ring chronologies, developed from cores from Pinyon pines growing on climatically sensitive sites in the north-central Great Basin, have been used to reconstruct precipitation and drought histories of the area from A.D. 1600 to 1982. Analysis of these hydrologic time series helps to place current climatic conditions into the perspective of the past 383 years (since 1600). ... The years 1934 and 1959 were the first and fourth driest while 1934 had the lowest July Palmer Drought Severity Index (PDSI) of the reconstructed records. Nevertheless, the decade of the 1930's is only the seventh driest since 1600; the decade 1953-1962 ranks as the second driest. The driest non-overlapping decade since 1600 was 1856-1865. Interestingly, the second wettest decade was 1932-1941. An examination of 30-year mean precipitation data shows that the driest 30-year period was 1871-1900; 1931-1960 ranks as the fourth driest. The current 30-year period (1951-1980) ranks twelfth.

East African Fisheries Research Organization Annual Report 1951

The examination of a considerable amount of data has led to the conclusion that Lake Victoria should be considered as many lakes within a lake. This is not a vague and seemingly obvious remark based on the superficial observation that it is a very large lake containing numerous islands and with a highly indented coastline, and therefore providing variable local conditions. Such local conditions would exist in any lake whose basin departed from a simple geometric form. But evidence has now been collected to show that really significant differences occur between different regions within the lake. These differences are apparent from a variety of data, including the nature of the bottom deposits, the chemical and hydrological condition of the water, the amount and kind of plankton and the distribution and abundance of the fauna. Our findings are as yet somewhat sketchy, and it will be a long time before it will be possible to draw an adequate picture of the various regions of the lake; it is however, of great value to have reached a position enabling us to form this general concept. The most striking and definite evidence is derived, as might be expected, from hydrological data. Details of this work are contained in the hydrological section of this report. Any data recorded below should be considered as applying only to the particular areas mentioned. In other words it would, to draw an obvious example be wrong to suppose that because fish grow at a particular rate in one part of the lake they will grow at the same rate or to the same size in other regions of the lake.