The Determination of the Food Grade of Streams
作者:
C.McC. Mottley,
H.J. Rayner,
J.H. Rainwater,
期刊:
Transactions of the American Fisheries Society
(Taylor Available online 1939)
卷期:
Volume 68,
issue 1
页码: 336-343
ISSN:0002-8487
年代: 1939
DOI:10.1577/1548-8659(1938)68[336:TDOTFG]2.0.CO;2
出版商: Taylor & Francis Group
数据来源: Taylor
摘要:
The volume and number of organisms per unit area of bottom is now widely used in determining the relative richness of streams. The food grade determined by the volume of organisms in square-foot samples is an important factor in the calculations used to determine the number of fish to plant per mile of stream. In spite of the fact that thousands of dollars may be wasted by making an incorrect estimate no one seems to have investigated some of the fundamental problems involved in the determinations. Some of these problems are: (1) What is an adequate sample; how many square-foot samples are needed to afford a reliable estimate? (2) What is the seasonal fluctuation in food organisms; can samples taken at different seasons be used as reliable estimates? (3) Do all the organisms taken in the samples become available to the same extent to the particular species of fish a stream is to support.
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