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Page 5691, results 142251 - 142275

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Publication Extents

Not all publications have extents, not all extents are completely accurate
Palaeomagnetism and potassium-argon ages of volcanic rocks of Ngorongoro caldera, Tanzania
C. S. Grommé, T. A. Reilly, A. E. Mussett, R. L. Hay
1971, Geophysical Journal International (22) 101-115
Natural remanent magnetization (NRM) has been measured in 21 lava flows and 1 tuff in the south-west wall of Ngorongoro caldera, Tanzania. The lowest three lavas are normally magnetized, the next two have intermediate directions, and the remainder are reversed; potassium-argon dating places the reversal at 2.45 My, corresponding...
Wells and springs in California and Nevada within 100 miles of point 37°15' N, 116°25' W, on Nevada test site
William Thordarson, B.P. Robinson
1971, Report
Studies of published and unpublished geologic and ground-water data, for an inventory of 6,032 wells and 754 springs in parts of Inyo and Mono Counties, California, and Clark, Esmeralda, Lincoln, and Nye Counties, Nevada, reveal the following information:A complex sequence of granitic, metamorphic, volcanic, and sedimentary rocks of Precambrian to...
Water resources of the Coamo area, Puerto Rico
Ennio V. Giusti
1971, Report
This study, like other similar studies, was made possible by a cooperative water-resources program between the U.S. Geological Survey and the Puerto Rico Water Resources Authority (at the time), representing also the Puerto Rico Aqueduct & Sewer Authority and the Puerto Rico Industrial Development Company.This report covers the hydrologic investigation...
Open-channel integrating-type flow meter
K.C. Koopman
1971, Report
A relatively inexpensive meter for measuring cumulative flow in open channels with a rated control,. called a "totalizer", was developed. It translates the nonlinear function of gage height to flow by use of a cam and a float. A variable resistance element in an electronic circuit is controlled by the...
Application of remote sensing techniques for appraising changes in wildlife habitat
Harvey K. Nelson, Albert T. Klett, John E. Johnston
1971, Conference Paper, International Workshop in Earth Resources Survey Systems
An attempt was made to investigate the potential of airborne, multispectral, line scanner data acquisition and computer-implemented automatic recognition techniques for providing useful information about waterfowl breeding habitat in North Dakota. The spectral characteristics of the components of a landscape containing waterfowl habitat can be detected with airborne scanners. By...
Biology of larval sea lampreys (Petromyzon marinus) of the 1960 year class, isolated in the Big Garlic River, Michigan, 1960-65
Patrick J. Manion, Alberton L. McLain
1971, Technical Report 16
The early life history of the sea lamprey, from hatching to the first capture of metamorphosed individuals, is described from observations on a known-age population isolated in a tributary of southern Lake Superior. The population had its origin in the spring of 1960, when 722 sea lampreys nearing spawning condition...
The white-crowned pigeon: A fruit-eating pigeon as a host for Trichomonas gallinae
R. M. Kocan, A. Sprunt IV
1971, Journal of Wildlife Diseases (7) 217-218
Trichomoniasis resulting from infection by Trichomonas gallinae was observed in 12 laboratory reared white-crowned pigeons (Columba leucocephala). A field survey of nestlings in the Florida Keys revealed a prevalence of 88% T. gallinae carriers but no evidence of trichomoniasis could be found among the wild birds....
Fishery science
R. E. Lennon
M.J. Walker, editor(s)
1971, Book chapter, Sport Fishing USA
Abstract not submitted to date...
Ship canals and aquatic ecosystems
William I. Aron, Stanford H. Smith
1971, Science (174) 13-20
Through a combination of ecosystem homeostasis and the perversity of man and nature, oftentimes the significant biological changes effected by environmental modifications are not detected until long after the initial change has taken place. The immediate impact, which may range from the spectacular to the undetectable, is a deceptive measure...
Effects of temperature on electrolyte balance and osmoregulation of the alewife (Alosa pseudoharengus) in fresh and sea water
Jon G. Stanley, Peter J. Colby
1971, Transactions of the American Fisheries Society (100) 624-638
A study of the effects of temperature and salinity on ionoregulation in the alewife, Alosa pseudoharengus, revealed that concentrations of sodium, potassium, and calcium in plasma and muscle were similar in fish adapted to fresh water and those adapted to sea water. The non-stressed alewife is apparently an excellent...
Alewife dieoffs: Why do they occur?
Peter J. Colby
1971, Limnos (4) 18-27
Periodid midwinter, early spring, and summer mortalities of alewives (Alosa pseudoharengus) have been common in the Great Lakes since the first appearance of the silvery marine invader in Lake Ontario in the mid-1870's. In 1967 a nationally publicized dieoff of tremendous magnitude (estimated at several hundred million pounds of...
Giant American brook lampreys, Lampetra lamottei, in the upper Great Lakes
Patrick J. Manion, Harold A. Purvis
1971, Journal of the Fisheries Research Board of Canada (28) 616-620
Five female American brook lampreys, Lampetra lamottei, collected in lakes Michigan and Huron averaged nearly twice as long and about six times as heavy as American brook lampreys of normal size. Three factors suggested that the giant lampreys may have fed parasitically after metamorphosis: morphological adaptations of the species for parasitic...
A basket for washing benthological samples
James H. Selgeby
1971, Transactions of the American Fisheries Society (100) 590-591
Since benthological samples collected with dredges are usually too large to be preserved in toto, a washing method must be employed to reduce the sample volume without losing or damaging the organisms. Traditionally, the sample is washed in a sieve until the volume is small enough for convenient handling...
Population biology of lake trout (Salvelinus namaycush) of Lake Superior before 1950
Gary T. Sakagawa, Richard L. Pycha
1971, Journal of the Fisheries Research Board of Canada (28) 65-71
Scale samples collected in 1948 were used to estimate the instantaneous total mortality rate (0.70) and growth for lake trout (Salvelinus namaycush) in Lake Superior before the population had been significantly reduced by the sea lamprey (Petromyzon marinus). Indirect evidence indicates that the instantaneous natural mortality rate was probably 0.10–0.25....
Albinism in lampreys in the upper Great Lakes
Robert A. Braem, Everett L. King
1971, Copeia (1971) 176-179
Albinism in fishes is relatively rare except in some stocks of hatchery-reared salmonids. In the Petromyzonidae, only four albino lampreys have been reported....
Selective food preferences of walleyes of the 1959 year class in Lake Erie
John W. Parsons
1971, Transactions of the American Fisheries Society (100) 474-485
Stomachs were examined from 1,473 walleyes (Stizostedion vitreum vitreum) of the 1959 year class collected in western Lake Erie from June 1959 to October 1960. In the same period, the relative abundance and lengths of potential forage species were determined from trawl catches. The walleye fed almost entirely on fish....