ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[118:CFHPOI]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

摘要:

Experiments using commercial fertilizer in distilled water indicated that an N–P–K–CaCO3ratio of 4:1:1:8 gave most economical plankton production. Pond waters in Central Alabama were found to require the addition of nitrogen, phosphorus, potash, and lime for maximum fish and plankton production. For use in pond waters, the above ratio was used with the amount of phosphorus doubled, giving a 4:2:1:8 ratio of N–P–K–CaCO3. The application of this mixture of commercial fertilizers gave a fish production of 578 pounds per acre, compared to 134 pounds per acre in the unfertilized control.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[126:FFITNF]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

摘要:

The various symptoms and effects of ulcer disease are described and discussed. Data on the relative susceptibility of various species and age groups of trout are presented, as well as data concerning the methods of infection, rate of progress, and incubation period of the disease. Experimental evidence is given on the problem of healthy appearing fish which act as carriers of the disease. The effect of a number of drug treatments has been studied. An experiment was performed to determine the effect of diet and vitamins on the resistance of trout to the disease.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[136:OOUDOT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

摘要:

This study is based on 120 whitefish collected in northern Lake Champlain (Missisquoi Bay) in 1930 and on 175 whitefish taken in southern Lake Champlain in 1931. Since the whitefish population had not been exploited commercially after 1912 in United States waters and after 1915 in Canadian waters, its study should be of interest in showing the characteristics of a population practically untouched by man. Data have been presented on length frequencies, age composition, growth, coefficient of condition, sex ratio, standard length-total length relationship, and feeding habits. The data indicated that the Missisquoi Bay population was disturbed (probably by the early fall seining of 1930) before our samples were taken so that the original length distributions no longer existed. The southern Lake Champlain material, however, showed a consistency which indicated that the population had not been exploited to any extensive degree, if at all. When the northern population was compared with the southern the former was found to differ from the latter in the following respects, which differences pointed to some disturbance of the northern stock in the lake

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[152:TAGAFH]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[163:ASOTMO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[170:NAOFG]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[173:NOMINS]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[178:SMFTPT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

摘要:

Owing to the probable extinction of the native Michigan grayling, especial interest attaches to progress of experimental plantings of the Montana grayling in various Michigan waters. This report concerns the feeding habits of a population of the latter species established in a small landlocked lake in northern Michigan.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[188:FHOTMG]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor

摘要:

An intensive creel census in conjunction with monthly releases, during the fishing season, of legal-sized trout, approximately one-half of which were jaw-tagged or fin-clipped, furnished data for the evaluation of such plantings in the Pine River, Michigan. Nearly 8,500 hours of fishing yielded 3,171 brook trout and 3,333 rainbow trout for an average catch of 0.77 fish per hour. Forty-six per cent of the brook trout reported and 21 per cent of the rainbows were from these plantings. Incomplete records of the marked fish showed recovery of 19.8 per cent of 7,513 brook trout and 17.5 per cent of 4,007 rainbows planted. The catch per hour by weekly periods ranged from 0.32 to 1.35. The average catch per hour for the Pine was considerably higher than for the other streams that were covered by a similar census but not planted with large fish. The plantings influenced the catch for a period of from two to three weeks. Apparently few of these fish survive to the next season. Movement of planted fish was mainly upstream regardless of the method of planting. Within two weeks the fish which remained were uniformly distributed over the stream. “Spot” planting resulted in a larger percentage caught than did scattering by boat, but increased “meat fishing.” Every planting during the open season caused a decided rise in the catch of wild fish of the same species. It is concluded that although planting legal fish during the season temporarily and artificially increases the catch, it may deplete a stream of wild adults. This depletion will affect natural production and may result in poorer fishing in succeeding years. A program for planting legal-sized trout appears justified only in heavily fished waters incapable of supporting a permanent trout population during the summer or where no results from natural reproduction are possible, or where an overpopulation of stunted trout exists.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1938)68[196:RFEPOL]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1939

数据来源: Taylor