摘要:

A system for recording measurements of fish scales is described. Symbols to denote various features of life history and, in the case of doubtful features, to express the “degree of doubt” in a definite manner, are listed. Two alternative procedures for gauging the validity of scale interpretations are suggested.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[59:ASFRMO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

摘要:

A joint experiment was conducted during the spring of 1942 by the Fly Tyers Club and the Laboratory of Limnology and Fisheries, Cornell University to determine the catch per unit effort from a known trout population and to test some angling theories. A 2,000-foot section of Cascadilla Creek, on the grounds of the University Experimental Fish Hatchery was closed off by weirs. Experience has shown that the natural trout population in this area is for practical purposes non existent. One hundred and fifty 8- to 13-inch rainbow trout (Salmo gairdnerii), mostly wild stock, were planted on April 16. Twenty trout were used as replacement for trout killed and in addition 30 marked trout were planted on May 11, increasing the theoretical population to 180 fish. Thus a total of 200 trout were involved in the experiment. Fishing pressure was supplied by seven members of the Fly Tyers Club and complete catch records were kept. The stream was fished on 54 days between April 17 and June 12 during which 307 hours were expended to catch 601 trout. Thus each trout was caught an average of 3 times and the seasonal catch per unit effort was about 2 trout per hour. When the fishing period is divided into nine 6-day periods no significant difference may be demonstrated in the catch per unit effort for the several periods. Although consistently good fishing was produced, all effort expended was not fruitful. About 20 per cent of the anglers caught no trout. A ratio of 1:5.5 was observed in the catch of marked and unmarked trout, which approximates the theoretical of 1:5. A marked downstream movement was noted among newly planted trout. Temperatures as high as 76° F. did not noticeably affect the interest of the trout in artificial lures. In a wet fly experiment five anglers fished five patterns on 5 days, the arrangement being distributed at random with the specification that each pattern be used once by each angler and once each day. Standardized terminal tackle was used and each lure was fished for 2 hours a day. A total of 112 trout was caught. When the data were analyzed by analysis of variance, no significant differences could be demonstrated for the various flies during the 5-day period; differences between anglers and between fishing days were highly significant. In a similar experiment involving the use of four dry flies (gray and black bi-visible type flies with clipped and unclipped hackles), a total of 91 trout were caught in the 4 days of fishing. No significant differences could be shown between flies, days or anglers. It appeared that the black flies were more effective than the light gray ones on dark overcast days.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[63:AEBTFT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[71:TCMFCA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

摘要:

Experiments were conducted to determine the riboflavin and pantothenic acid requirement of brook trout. Groups of trout were fed diets containing different levels of the vitamins and after a period the fish were killed and their livers analyzed micro-biologically to determine the amount of storage of the vitamins. It was found that up to a maximum, the amount of storage increased with the level of the vitamins in the diet. When a maximum level was reached in the liver additional amounts in the diet did not increase the liver content. It has been tentatively concluded that brook trout require between 0.36 and 0.53 milligrams of riboflavin per kilogram of body weight daily and between 1.11 and 1.45 milligrams of pantothenic acid.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[81:TRAPAR]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

摘要:

Ages were determined and individual growth histories were calculated from the examination and measurement of the scales of 1,649 kiyis captured at seven localities in Lake Michigan in 1931 and 1932. The numbers of individuals employed for the investigation of other phases of the life history (such as length-frequency distributions, length-weight relationship, and sex ratio) varied according to the amount of data available or required.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[88:AAGOTK]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

摘要:

From May to November, inclusive, the kiyis of southern Lake Michigan (north to and including localities off Kewaunee, Wisconsin, and Frankfort, Michigan) characteristically inhabit depths of more than 50 fathoms, although small numbers commonly are taken in shallower water (as shallow as 20 29 fathoms). There is evidence that the occasional penetration of relatively large numbers of kiyis into depths of less than 50 fathoms in this area is the result of exceptional hydrographic conditions involving the disturbance of considerable masses of water.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[143:DAASSA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

摘要:

A section of the Blackledge River, 1.7 miles long, was blocked off by weirs and fish traps and a total of 4,757 marked brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Salmo gairdnerii) were stocked in the experimental area in three plantings. Only a small number of the marked trout attempted to leave the area as indicated by the 46 fish taken in the traps. Subsequent recapture of these trout, which were tagged, indicated no inclination to move any great distance. The mortality of the marked trout after planting was slight during the period of observation, except in one planting where the brook and brown trout stocked showed advanced symptoms of furunculosis. The total catch of marked trout during the season of April 17 to August 31 was 3,446 trout taken by 3,152 anglers spending 9,746 hours on the stream. There was about an 80 per cent return of the available population from each planting and from each of the three species of trout planted. Of the 97 unmarked trout which were caught, only 23 were judged to be “wild” fish, the others being recently stocked trout which had moved into the area from adjoining waters before the weirs were in place. The distribution of the angling pressure was such that each planting was depleted within a few days. About three-fourths of the total catch of trout made from any one planting was taken within four days of the date of stocking. The population of brook trout was depleted most rapidly, that of brown trout most slowly, and rainbow trout were intermediate. Only 5 days of fishing were provided during the season where the catch per unit of effort approached 1 trout per hour or more. There was a high correlation between the population of trout in the stream and the catch per unit effort, except in the second planting of brown trout. The relationship between the available population and the catch per unit effort showed progressively higher yields for the same number of trout as the season advanced. Because of the rapid population depletion, in only one instance could possible differences in behavior between newly stocked trout and those from previous plantings be noted. The number of brown trout caught from the second planting showed no correlation with the fishing effort while brown trout caught from the first planting at the same time were closely related to the fishing effort. The distribution of each angler's catch indicated that under a limit of 15 fish about one-third of the total number of anglers accounted for three-fourths of the catch on the first few days of fishing following each planting.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[166:PDIBBA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

摘要:

Analysis of the effect of hatchery plants of Atlantic salmon over a 70-year period on the maintenance of the Penobscot River salmon run shows that artificial propagation was not significantly more effective than natural propagation, but was more effective in later than in earlier years. The numbers that can be raised to a sufficiently large size before stocking to gain a material advantage over natural propagation are too limited to employ hatcheries for the maintenance of large runs. The chief role of the hatchery is to provide young fish for reestablishing former runs, and to increase the survival of young during the early period of restoration when the hatcheries can handle a significant proportion of the total eggs in the spawning run.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[188:TEONAA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

摘要:

A need for a simple and effective direct treatment for fish in ponds and troughs has long been apparent among fish-culturists. A direct treatment not only would obviate all need for handling fish already weakened by disease but it could be used as a routine prophylaxis to eradicate diseases in their earliest stages long before their presence is suspected.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[209:ATFCID]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor

摘要:

The total alkalinity of unpolluted waters in Tennessee streams can be generally related to the nature of the geological formations comprising the stream beds and soil provinces. Data accumulated from 371 localities in streams which are isolated in distinct and separate geological formations show that sixteen geochemical provinces may be recognized as individually effective in determining the character of fishable streams.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1944)74[223:GIOWAF]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1947

数据来源: Taylor