ISSN:0002-8487    

DOI:10.1577/00028487.1953.10492346

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1953.10492354

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1953.10492355

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

ISSN:0002-8487    

DOI:10.1577/00028487.1953.10492356

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

An investigation of the food chains leading to the production of Florida spotted gar, Lepisosteus platyrhincus DeKay, was conducted in a 3-mile section of the Tamiami Canal approximately 20 miles west of Miami. In this area these fish are extremely abundant, and those collected ranged in length from 10.5 to 24.4 inches. Collections of gar, forage fish, plankton, periphyton, bottom fauna, and physicochemical data were obtained at frequent intervals from February 20 to June 28, 1952. A total of 448 gar stomachs was examined, of which only 106 (23.7 percent) contained food. Stomachs of 572 specimens of fish, representing 9 species known to serve as food for gar, were obtained and the contents analyzed. Stomachs of fresh-water shrimp, Palaemonetes paludosa, and other invertebrates which entered into the food chains were examined.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1952)82[13:FRBFSG]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

On Escanaba Lake, Vilas County, Wisconsin, no bag, size, or season limits have been in effect from 1946 to the present time. Large catches of walleyes from 1948 through 1950 prompted the Wisconsin Conservation Department to estimate the available stock in the lake by a tagging experiment. A total of 984 adult walleyes were tagged. In a subsequent creel census of fisbermen from May 12 to October 15, 1951, 202 tagged fish were recaptured in a total catch of 1,867 walleyes. By means of the Petersen formula the population of walleyes in the lake was calculated to be 9,102 as of May 11, 1951. Even with relaxed regulations, large catches by anglers, and no stocking of the species, continued recruitment through natural reproduction has prevented undue depletion of the walleye population.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1952)82[34:TWPIEL]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

Principal features of the technique are: attachment of the plastic tag by means of a nylon-thread loop prepared in advance of field work; use of a curved surgical needle with cutting edge and a split eye for application of the tag. The procedures for splitting the needle's eye and for applying the tag are described and illustrated by a series of photographs.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1952)82[42:TFTAOA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

The fishing, populations, and mortality rates of fishes in Gordy Lake, Indiana, were studied in 1950 by creel-census and mark-and-recapture techniques. Gordy Lake has an area of 28.5 acres and a maximum depth of 35 feet.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1952)82[48:VSOTFP]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

A total of 733 native lake trout was tagged at two widely separated localities in Lake Superior; subsequent recaptures numbered 155 fish (21.1 percent) during the year following marking. In October 1950, 116 large lake trout (average total length, 27.3 inches) were tagged near Keweenaw Point, Michigan. Fifteen (12.9 percent) were recovered during the first year at points as far west as the Gooseberry River, Minnesota (190 miles), north to the Slate Islands, Ontario (95 miles), and east to Grand Marais, Michigan (100 miles). Nine fish (7.8 percent) were recovered during the second year after marking. Returns from 617 tagged lake trout of smaller size (average length, 18.2 inches) released in the Apostle Island region of Wisconsin during the period June 12 to August 6, 1951, numbered 140 (22.7 percent) during the first year. Of these fish, 90 percent were recaptured within a radius of 50 miles of the points of release. Seventy-six percent were caught in Wisconsin, 14 percent in Minnesota, and 9 percent in Michigan waters. The fish retaken in Michigan had moved 120 to 255 miles between the time of release and recapture, traveling as far east as Grand Marais. Lake trout recaptured at distances of more than 50 miles from the tagging locality were of larger average size than marked fish caught within this radius.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1952)82[68:TMOTLT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor

摘要:

To determine the practicability of fertilizing trout lakes in Michigan, series of applications of inorganic, commercial fertilizers were made to four trout lakes which ranged in methyl-orange alkalinity from 138 to 192 p.p.m. Two additional lakes, left unfertilized, were used as controls. Increases in epilimnial phosphorus content, which occurred as a result of fertilization, were only temporary; there was no evident difference between total phosphorus concentrations in the fertilized lakes and the unfertilized lakes during the summer following 2 years of fertilizer applications. The rate of disappearance of added phosphorus from epilimnial waters was shown statistically to be related to alkalinity. Increases in total phosphorous concentrations occurred within the hypolimnia and, up to a certain point, were correlated with the alkalinity of the lakes. The theoretical lower limit of the alkalitrophic, or excess calcium, condition seemed to be between 120 and 160 p.p.m. methyl-orange alkalinity. The postulate that the ratio of marl to organic matter is important in the control of adsorption and regeneration of phosphorus in lakes was supported. It was assumed that this factor, as well as the descent of phosphorus from epilimnial to hypolimnial layers, accounted for the nearly complete disappearance of added phosphorus from epilimnial waters of the fertilized trout lakes.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1952)82[78:RBAAAA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1953

数据来源: Taylor