ISSN:0002-8487    

DOI:10.1577/00028487.1942.10493093

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1942.10493100

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1942.10493101

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1942.10493102

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1942.10493091

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

摘要:

The yield of our American fisheries can be increased 46 per cent during a National emergency. The 1938 yield of the fisheries of the United States and Alaska was 4,254,000,000 pounds. Under conditions of a war-time emergency necessitating greater supplies of food and industrial by-products, this yield could be increased to 4,628,000,000 pounds in 3 or 4 years and eventually a sustained total of about 6,200,000,000 pounds could be produced each year. Minor modification of methods of utilization will permit an increase in food production from the fisheries of 86 per cent.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1941)71[61:CTFSMF]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

摘要:

No one has apparently made use of efficient statistical procedures for the “back-calculation” of the growth of fish from the measurements of the scales. If it can be shown that the scale provides an unbiased estimate of the length or “size” of the fish, then there is no real necessity for the conversion of scale size into body size for comparisons of the growth. A study of data obtained from the rainbow trout population of Paul Lake, British Columbia, showed that scale size could be regarded as an unbiased estimate of the length of immature 2-year-old male and female rainbow trout under the ordinary conditions of sampling by angling. An example is given to show how the growth of rainbow trout in 4 separate years could be compared by the direct use of the scales. It is known from previous studies that a significant reduction in size occurred during these years. A corresponding reduction in the size of the scales was also found. It is suggested that the method provides a direct index of the growth of the fish which can be used to compare growing conditions from year to year.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1941)71[74:TUOTSO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

摘要:

Several features of impoundments and reservoirs, either inherent or the result of operations at the dam, can reduce and limit the biological productivity of an impoundment and consequently the fish production of its waters. Among these characteristics are the stagnation of large masses of water, the removal of food materials in the waters drawn out of the reservoir, the limited lateral areas of shallow water around the margin of the impoundment, extensive fluctuation of water level, and continued and often heavy silting in of the bottom.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1941)71[80:FI]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

摘要:

Various submerged weeds form tangled masses of vegetation in shallow, clear-water ponds in the Southeast. It is difficult or impossible to fish in such weed-infested ponds, and the weeds protect the small fish from carnivorous species so well that overcrowding develops and stunted populations result. Hence, the control of submerged weeds is an important problem in pond management.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1941)71[94:TUOFFC]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor

摘要:

The principal causes of stunted populations in impounded waters in the Southeast are: Overstocking, absence of sufficient carnivorous fish, and heavy weed growth in ponds. Recommended management practices for the correction of these conditions are: (1) weed control, (2) stocking with largemouth black bass, (3) fertilization to increase the food supply, and (4) heavy fishing to reduce the number of fish.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1941)71[102:TMOPWS]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1942

数据来源: Taylor