摘要:

Under experimental conditions legal-sized brook trout, brown trout, and rainbow trout exposed to 110-volt alternating- and 230-volt direct-current electricity suffered an average mortality of 6.4 percent. Immediate mortality amounted to 4.3 percent and the delayed type accounted for 2.1 percent of the deaths. Of the trout exposed to alternating current 11.1 percent died whereas only 2.0 percent of those treated with direct current were killed. There appeared to be no relationship between mortality and either fish size or trout species. Both types of units are considered to be acceptable for stream population studies.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[93:FMCBES]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

Studies of the median toxicity thresholds for 10 species of fish in brine wastes from a single oil well showed a range of the thresholds from 4.3 to 11.2 percent of the original brine by volume. A similar study on 10 kinds of invertebrates revealed a range of thresholds from 1.8 to 8.7 percent. Thresholds were expressed as percentage volume of the original waste since the brine contained large amounts of calcium, magnesium, potassium, and sodium as well as chloride ions. However, computations of hypothetical combinations of chlorides in the brine indicated sodium chloride to be present in such proportions as to be most toxic.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[97:TOBWFO]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

As a means of evaluating the effects of harvesting minnows in a small stream, a study was made of the minnow population in a section of Jordan Creek in east-central Illinois. Nine collections of minnows were made with an electric fish shocker from August 1950 through October 1953. These collections represented a large proportion of the existing population. The yields for the corresponding months of each of the succeeding years increased progressively. The minnow population as a whole exhibited annual cycles of abundance and of average weights of individual fish. Each species responded differently to various environmental factors and to the continuous cropping. Shocking, which is a more effective method of harvesting minnows than is seining, did not reduce the minnow population in the study section of Jordan Creek longer than a few months. The natural fluctuations of the minnow population made it difficult to measure the effects of cropping with the electric shocker.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[110:MPIASI]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

The physico-chemical characteristics of ponds of three strip-mine areas in Southern Illinois were observed under both winter and summer conditions. In addition to a general discussion of the areas, a detailed report is made on dissolved oxygen as associated with thermal stratification, and on pH and specific conductance. Observations were also made on the plant life and fishes of the ponds. The more important findings included high concentrations of dissolved oxygen in the thermocline, pH values ranging from 3 to 8, and extremely high specific conductance. Chemical conditions were not associated with the age of the ponds. The ponds have many characteristics of oligotrophic lakes and the possibilities for fish production are limited. The most common fishes of the ponds were the green sunfish (Lepomis cyanellus), bluegill (Lepomis macrochirus), and largemouth bass (Micropterus salmoides). Some ponds were devoid of fish life.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[117:PCOPIT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

During March and April of 1953 and 1954 walleyes were tagged and released in Muskegon Lake before they ascended the Muskegon River on a spawning migration. Recoveries of the tagged walleyes were made by dip nets below Newaygo Dam 39 miles upstream. Estimates of the numerical abundance of the spawning runs computed from these recaptures (ratio of tagged to untagged walleyes in the dip-net catch) were about 114,000 individuals in 1953 and about 139,000 fish in 1954.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[125:NAAUOA]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

The spawning efficiency of chinook salmon (Oncorhynchus tshawytscha) in Fall Creek, a tributary of the Klamath River in northern California, was measured during four runs, 1950–1954, inclusive. In these years the following numbers of pairs of spawners were allowed to enter the stream: 750, 500, 300, and 300, respectively. Estimates of the total egg production of these fish were based on sampling. The numbers of downstream migrant fingerlings resulting from each of these spawning runs were computed by trapping the migrants in a known fraction of the stream flow. The percentages of potential eggs resulting in migrants leaving Fall Creek in the years sampled were 7, 10, 9, and 32, respectively. There appears to be an inverse correlation between the size of floods during incubation and the efficiency of spawning.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[137:EOCSSI]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

The northern pike, Esox lucius, is a ready source of food in many arctic and subarctic areas of North America. Because little information is available concerning lipids in fresh-water fish a study was made of these substances in the northern pike. Specimens were caught on hooks in Lake Minchumina, Alaska. Blood and liver were analyzed for fatty acids, sterols, and phospholipids. The pike is distinctive in having a rather high liver cholesterol–0.89 percent of fresh tissue. The other lipids are not unique but fall into the pattern for animals previously studied. However, marine fish in general have consistently more fat in the liver than does the northern pike.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[150:LITNP]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

Sterility was observed in female brook trout that were treated with sulfamerazine at frequent intervals for 2 years to control endemic furunculosis. Feeding sulfamerazine for a period of 8 months caused massive kidney damage similar to that observed in humans who develop allergies to “sulfa” drugs. Kidney damage of the type observed would probably cause renal insufficiency which would handicap any physiological function including reproduction. Feeding sulfonamides for periods up to 13 weeks did not produce kidney damage.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[155:STIBT]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

Bottom trawling by the U. S. Fish and Wildlife Service motor vessel Cisco in Lake Superior in 1952–1953 revealed a large population of a tiny whitefish, Coregonus (Prosopium) coulteri, which has been reported previously only from northwestern North America. The hiatus in range, from Lake Superior to the Columbia River basin, is the greatest known for a North American freshwater fish. Although minor structural differences characterize the disjunct populations of the pygmy whitefish, these are not deemed worthy of nomenclatorial recognition. Comparisons with related species indicate that the pygmy whitefish is distinctive in the small size, large scales, few vertebrae, few pyloric caeca, and in other characters.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[161:TPWCCI]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor

摘要:

The use of stratified periods, random sampling days and voluntary information provided by the participating anglers provided a method of creel census which required a minimum of working days and still allowed constant highway travel in the working area to flow uninterrupted. A maximum of two men on 24 days was used to census a season total of nearly 7,000 anglers on 24 miles of the stream.

ISSN:0002-8487    

DOI:10.1577/1548-8659(1954)84[200:TCCOTL]2.0.CO;2

出版商:Taylor & Francis Group    

年代:1955

数据来源: Taylor