摘要:

Brook, brown, and rainbow trout were fed diets containing various levels of niacin and biotin. After a period, trout were killed and their livers analyzed for the vitamin content. The diet level of the vitamin causing maximum storage in the liver was considered as the tentative requirement of the trout. The requirement for niacin was found to be between 3.0 and 4.1 milligrams per kilogram of trout daily. Maximum storage was between 34 and 38 micrograms per gram of liver. There was no difference in requirement between species or the two temperatures of the experiment. There was a difference between species in their requirement for biotin. Brook and rainbow trout needed between 6,700 and 26,880 milli-micrograms per kilogram of weight and brown trout between 43,360 and 76,980 milli-micrograms. Temperature of the experiment had no effect upon the requirement. Maximum storage was approximately 1,100 milli-micrograms per gram of liver in brown trout and about 1,200 milli-micrograms for brook and rainbow trout.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1947)77[152:TNABRO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

One of the important features of a research program on blackfly control in Alaska in 1947 was an investigation of the effects of several recently developed insecticides on fish inhabiting blackfly streams. Trough and stream experiments were conducted, with rainbow trout as the principal test species and utilizing also Dolly Varden trout, king salmon, silver salmon, and red salmon. DDT, benzene hexachloride, chlordan, and chlorinated camphene were the chief toxicants tested and were applied as xylene-Triton emulsions, acetone solutions, and, in some experiments, as fuel-oil solutions and Velsicol AR-50 solutions. Blackfly larvae and other stream-bottom organisms were tested with the fish in both trough tests and in stream treatments. The minimum lethal concentrations for most of the chemicals were determined in the troughs for the three groups of organisms, and margins of safety between blackfly larvae and fish and fish-food animals were tested in the stream.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1947)77[160:EOSIOT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

摘要:

Although the whitefish has by no means ranked first from the standpoint of production, it has always been an important commercial species in Lake Erie. Trends in the output of whitefish have differed in the United States and Canadian waters of the lake. The 1893–1946 average annual yield of 1,201,000 pounds in the United States was only 38.3 percent of the 1879–1890 mean of 3,133,000 pounds, whereas in Canada the more recent (1907–1946) average annual take of 1,397,000 pounds has been 5.48 times the 1871–1906 mean of 255,000 pounds. The United States fishery was centered in the western part of Lake Erie (61.5 percent of the production in Michigan and Ohio) before 1921 and in the eastern part (62.6 percent in Pennsylvania and New York) in 1921–1946. The eastern part of Lake Erie (east of Port Burwell) dominated the Canadian production in 1900–1909 (65.4 percent) and in 1922–1946 (57.2 percent) but the western end was the more productive in 1871–1899 (79.8 percent) and 1910–1921 (69.7 percent).

ISSN:0002-8487    

DOI:10.1577/1548-8659(1947)77[178:AAGOTL]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1949.10493262

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1949.10493263

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1949.10493264

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1949.10493265

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1949.10493266

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1949.10493268

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1949.10493269

出版商:Taylor & Francis Group    

年代:1949

数据来源: Taylor