ISSN:0002-8487    

DOI:10.1577/00028487.1950.10493288

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1950.10493289

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1950.10493290

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1950.10493291

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1950.10493292

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

摘要:

An attempt was made to reduce the numbers of longnose or northern suckers and mountain whitefish in Pyramid Lake, Alberta, in the hope of improving the survival of introduced rainbow trout. The lake has an area of 320 acres and a maximum depth of 64 feet. Examination of its physical and biological characteristics show it to be oligotrophic and somewhat more productive than most of the other alpine lakes studied in the area. The results of a marking-and-recovery program suggested a population in the order of 27,000 fish of nettable size of which 75 percent were suckers, 22 percent mountain whitefish, and 3 percent game trout of three species. The removal of 27,600 longnose suckers in 7 years has eliminated the older age groups and has reduced the average weight of suckers caught from 5.5 to 1.6 ounces. However, the survival rate of young suckers, less than nettable size, increased. The removal of suckers has not been accompanied by any noticeable improvement in the survival of rainbow trout either during the 5 years of removal or in the 3 years which followed. The present game-fish harvest is less than that expected from a lake of this size. It is suggested that further fish-cultural efforts in this lake be concentrated on the lake trout.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1948)78[13:RITLSP]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

摘要:

Two types of hydraulic press have been designed and constructed for making impressions of fish scales on cellulose acetate. One of these presses is hand-operated; the other is powered by an electric motor. Each has a heated die to soften the plastic material. In growth studies the use of acetate impressions in place of the scales themselves results in a marked saving of time, materials, and storage space. Operation of the scale press is relatively simple, and the technical difficulties are relatively few and are corrected easily. Certain modifications and improvements are suggested.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1948)78[32:HPFMIO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

摘要:

Recreational fishing contributes a substantial amount to Florida's economy. A variety of game and rough fishes of which the more important are listed, make up the catch.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1948)78[38:MOFFF]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

摘要:

The gradual decline of the Columbia River salmon fishery has been brought about through deforestation, pollution, over-fishing, unscreened water diversions, and construction of dams within the watershed. The latter is believed to be the major contributing factor.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1948)78[42:TFDPIT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor

摘要:

During the fall of 1947 and the late summer of 1948, outbreaks of ulcer disease occurred among brook trout fingerlings at the Leetown station and other hatcheries. From the ulcers, blood, and kidneys of the diseased trout were isolated bacteria which could be successfully cultivated only on media to which blood or fish-tissue extract had been added. Some characteristics of these bacteria are described.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1948)78[56:ACTTEO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1950

数据来源: Taylor