• Life history and management of the grayling in interior Alaska

      Wojcik, Frank J. (1955-04)
      Field work on the Arctic grayling was conducted from September, 1951, to May, 1953; data on movements, spawning, food habits, sex ratios, and population dynamics were obtained. Returns on 1,222 tagged grayling varied from 0 to 20 per cent with areas. No returns were obtained from 165 fin-clipped fish. Fish entered the streams in the spring as soon as water started flowing, the dates varying from March 15 to May 9, 1952. Spawning in the Little Salcha River during 1952 is believed to have occurred between June 12 and June 16, Of 262 grayling checked for maturity, 18.7 per cent were mature in their fourth summer, 45 per cent in their fifth summer, and all by their sixth summer. Sex ratios obtained for adults varied with areas. The average sex ratio found for all areas was 79 males per 100 fem ales. The rate of growth was determined for grayling from six areas. The average increment for class V fish varied from 2.7 to 4.6 cm. per year. Aquatic insects were the main food organisms taken by grayling. Some terrestrial insects, fish, fish eggs and vegetable, matter were also taken. In view of the findings made in this study, overfishing appears to be the major cause of the decline in the sizes of grayling populations along the highways in the Fairbanks area. A twelve-inch minimum size limit is apparently the best management procedure, although an area closure is advisable for overfished spawning runs.
    • Range, movements, population, and food habits of the Steese-Fortymile caribou herd

      Skoog, Ronald O. (1956-05)
      The Steese-Fortymile caribou (Rangifer arcticus stonei Allen) form one of the most economically important herds in Alaska. This study of the herd took place from September, 1952, to December, 1955, under the auspices of the Alaska Cooperative Wildlife Research Unit at the University of Alaska and of the Federal Aid in Wildlife Restoration branch of the United States Fish and Wildlife Service, Project W3R. The Steese-Fortymile range occupies about 35,000 square miles of east-central Alaska and the Yukon Territory, lying mainly between the Tanana and Yukon Rivers. The terrain is mountainous, but not rugged; roads and towns are scarce, and a maximum of 60,000 people live on the fringes. Seven major plant communities comprise the range vegetation, three of them covering 60 to 70 per cent of the area and furnishing the bulk of the food for caribou. The carrying capacity is computed to be 70,000 to 90,000 caribou. The erratic and continual movements of caribou characterize this game species. Their movements vary from day to day and season to season. Most of the traveling takes place during the early morning and late afternoon; major seasonal movements take place in the spring and fall. Past and present data provide a general picture of the movement pattern of this herd throughout the year. The Steese-Fortymile herd dwindled from a peak of about 500,000 animals in the late 1920's to a low of 10,000 to 20,000 in the early 1940's. The decline is attributed to a population shift. The present population contains at least 50,000 animals and is increasing steadily. Reproduction was high during the years 1950 to 1955. The rut takes place during the first two weeks of October; most of the calves are born during the latter half of May, following a gestation period of about 33 weeks. Valuable information on caribou behavior during the calving period is presented. Counts taken in May show that at least 50 per cent of the calves survive the first year. Wolf and man are the most important mortality factors affecting this herd. The total annual mortality, excluding calves, is estimated at eight per cent. Sex and age data from composition counts and hunter-checking-station operations indicate that this herd is young and that the sex ratio approaches 100:100. The annual increment for the herd is computed to be 10 to 15 per cent. Caribou are cursory feeders and eat a wide variety of plants. The main periods for resting and feeding occur during the middle portions of the day and night. The caribou’s diet hinges upon the available food supply, and thus varies with the seasons. In winter, the diet consists mostly of lichens, grasses, and sedges, with browse plants of some importance; data from 23 stomach-samples are presented. In spring, the new shoots of willow, dwarf birch, grass, and sedge are most important; information is based only on field observations. In summer, a wide variety of plants are eaten; willow and dwarf-birch foliage are of greatest importance, followed closely by grasses and sedges; data from 27 stomach-samples are presented. In fall, the diet shifts from a predominance of woody plants and fungi in late August to one of lichens, grasses, and sedges in late September; data from 70 stomach-samples are presented. The problems of data-gathering are discussed, as related to management practices. The contributions made by this report are outlined, and the important information still needed for proper caribou management is listed.
    • A review of waterfowl investigations and a comparison of aerial and ground censusing of waterfowl at Minto Flats, Alaska

      Rowinski, Ludwig J. (1958)
      The Minto Flats is one of the important waterfowl concentration areas of interior Alaska. Aerial surveys and ground studies were initiated in this area in 1950 and have continued in succeeding years. This study began in September, 1955, as a research project of the Alaska Cooperative Wildlife Research Unit. The study was financed largely by Pitman-Robertson Project Alaska W-3-R. The Minto Flats is an area of about 450 square miles, located about 35 miles west of Fairbanks. The important nesting species are scaup, pintail and widgeon. The Minto Lakes area serves as an important molting and flocking area for these and other species. Climatically the Minto Flats resemble the rest of interior Alaska. Water levels in the area are highly variable and influence the vegetation and breeding. Minto Lakes, Big Lake, and the Tolovana Flats were selected for concentrated study in 1956. During the 1956 field studies, data were collected for comparison with data available from previous years. Waterfowl production in the Minto Flats area is affected principally by weather, changes in water level, and predation. Among the factors influencing censusing are the census methods, stratification, and sample size. Enumeration of waterfowl is affected by differences in the visibility of birds, population composition, environmental conditions, and the accuracy of observers in relation to the other variables and in regard to individual partiality and talent. The difference between observers, when analyzed statistically points out the need for continuity of observers with known levels of ability. Breeding bird census figures from aerial surveys from 1950 t o 1956 are not comparable due to differences in census methods. Aerial brood surveys are valuable for determining year to year production trends while ground surveys provide data on brood species composition. Together they are the best guide to waterfowl production. Nesting studies have provided some data on nesting terrain, clutch size, and nesting success. The effect of nest hunting on the breeding population and the time necessary for obtaining an adequate sample indicates that nest hunting is not an economical or accurate means of measuring yearly productive success. Aerial surveys are recognized as the most feasible way of measuring production if the accuracy of the information gathered from the air can be increased.
    • Snowshoe hares in Alaska, II. Home range and ecology during an early population increase

      Trapp, Gene Robert (1962-02)
      A segment of a continuing study of Snowshoe Hares was conducted from May 1960 to November 1961, near College, Alaska. Objectives regarding home range, reproduction, behavior, age-determination criteria, and census methods were achieved by Iive-trapping and snaring. The Schnabel (Krumholz) formula and Petersen ratio for estimating population size were invalidated by differential trap response. The calendar graph, Webb strip-census, Hartman toe-clip ratio, pellet count, and road survey all proved poor or useless as used during this study for estimating hare abundance in this area. An increase in hare sign in marginal habitat between 1958 and 1961 indicated an increase in population density. Some hares were caught many times in succession in the same trap. Many more avoided traps, some for periods of nearly two years. Inclement weather restricted movements of hares. Adult and juvenile sex ratios were 1:1. The season of births extended from mid-May to early August. There was a mean of 4.6 fetuses per female per pregnancy. Hare parasites noted were: Mosgovoyia pectinata, Taenia pisiformis, Dirofilaria scapiceps, Obeliscoides cuniculi, Protostrongylus bouqhtoni, Haemaphysalis leporispalustris, and Hoplopsyllus glacialis. Exclusive-boundary-strip home range decreased significantly at the .01 level from 14.5 acreas at a low population density to 13.1 acreas at a higher density. A juvenile female hare made the maximum despersal movement noted, 1.6 miles. Snow collected on vegetation formed winter cover for hares. Hares used burrows occasionally. A sound resembling a low click ("tch") was observed in hares. Possible displacement behavior was observed in hares. Two litters were found in simple depressions in the leaves, and one in a nest-like form. Leverets less than 24 hours old could move from their place of birth. A hare's foot color cannot be used as an age criterion in Alaska in summer, since adults may have brown, white, or mottled hind feet. The epiphyseal groove appears to close at approximately seven months. Juvenile males can be recognized until December by a short, stubby penis, and juvenile females by a short, blunt vulva and lack of palpable teats. A combination of body weight and hind-foot length is recommended for determining the ages of juvenile hares. A lens weight of 160 mg. can be used to separate hares less than a year old from older hares.
    • Bioassay and distribution of thiamine in the sea

      Natarajan, Kottayam Viswanathan (1965-05)
    • Geomagnetic micropulsations with emphasis placed on the properties and interpretation of pearls

      Dawson, John Alexander (1965-05)
      The thesis can be divided into three somewhat divergent parts, historical, experimental, and theoretical. The first chapter is an attempt to survey the literature concerning all types of micropulsations. A classification scheme is presented which is in agreement with that adopted by the IAGA at Berkeley, California in 1963, though I have retained the older nomenclature. A summary of the known properties of the various types of micropulsations is presented along with a discussion of controversial points. The next four chapters describe the experimental work performed in cooperation with the Boulder laboratories of NBS, and some observations resulting therefrom. In contrast to the first chapter this section is confined exclusively to pearls. Pearls were found to show little correlation with ionospheric and magnetic data. Exception should be made for two riometer absorption events which can possibly be matched against pearl events. As about 60 to 70 per cent of the pearls observed at College and Macquarie can be matched against each other, pearls are considered to occur simultaneously at conjugate points. At College pearls are shown to be polarized in a plane perpendicular to the magnetic field line. The last chapter develops hydromagnetic wave theory as is pertinent to propagation through the upper magnetosphere. The various assumptions used are examined critically to justify their applicability to the upper magnetosphere. It is found that the magnetosphere below 10,000 km cannot be considered uniform for waves in the 1 cps range. Hence, harmonic solutions to the wave equation cannot be used and more elaborate techniques to treat this problem must be developed. It is suggested that pearls are Alfven waves which propagate along field lines to auroral latitudes. These waves then couple to other modes for propagation to lower latitudes.
    • On the nature and shape of noctilucent cloud particles

      Chao, Jih-Kwin (1965-05)
      The exact theory of the scattering of light from spheres, double-layer spheres, infinite long cylinders and coaxial cylinders is presented here in detail. The theory of scattering from spheres and infinite long cylinders is then applied to the noctilucent Cloud (NCL) problem. The intensity and polarization versus scattering angle, particle size, and wavelength for spherical particle scattering with index of refraction 1.33 (corresponding to ice and stone) were calculated with an IBM 1620 electronic computer and the results are compared with the available experimental data. The experimental data was also compared with the results of Deirmendjian, Clasen, etc., allowing conclusions with regard to the possibility of spherical pure metallic particles. The results indicate that the NLC particles are either stony dust or ice coated stony dust rather than pure metallic in nature. Consideration is given to the possibility of detecting through polarization and spectrographic studies the possible growth of NLC particles resulting from the formation of ice on them. If the NLC become visible only as a result of an increase of the number of particles, then the shape of the polarization versus scattering angle curve will not change, and the intensity versus wavelength curve will not change in shape but only in amplitude. However, if particle growth is responsible for the NLC becoming visible, then the shape of the polarization versus scattering angle curve will change. Careful experimental observations of these quantities should then answer this question about particle growth. A detailed analysis of the NLC particle sampling data obtained in Sweden during 1962 is made. A particle size distribution of the form Nα(diameter)⁻⁴ is required for the sampling data to be consistent with the polarization measurements that have been made.
    • Dynamo action in the ionosphere and motions of the magnetospheric plasma

      DeWitt, Ronald N. (1965-05)
      This thesis presents a study of the dynamic interaction which takes place between the magnetospheric plasma and the underlying neutral atmosphere; it is hoped thus to g a m a better understanding of the effects of this interaction upon the steady state configuration of the magnetosphere. The neutral portion of the atmosphere (the neutrosphere) and the overlying ionized regions (the upper atmosphere and magnetosphere) may be regarded as two distinct dynamic domains that interact in a region of transition occurring between 100 and 150 km over the earth. The neutrosphere because of its greater mass will dominate the motion, and the magnetospheric plasma can be expected to undergo motions related to those of the upper neutrosphere and transition region. However, the geomagnetic field restricts the motion of the magnetospheric plasma to a particular class, allowing one to consider the magnetospheric motion to be constrained. Motions in the transition region of the class not permitted the magnetospheric plasma will give rise to forces against the constraint. The reaction of the constraint on the atmosphere of the transition region takes the form of a Lorentz force x B where J is the current responsible for the well known solar quiet day daily magnetic variation (Sq). The explanation for the production of this current in the transition region has traditionally been presented in terms of a dynamo-like electromotive force generated by motions of the conducting atmosphere through the magnetic field, whence the transition region is aptly named the dynamo region. The Lorentz force represented by this current constitutes a significant term in the equation of motion for the dynamo region. Another important term arises from eddy viscous stresses immediately below the dynamo region. The equation of motion for the dynamo region must thus include such forces as well as the pressure gradient and Coriolis terms. However, our almost total ignorance of the eddy viscous stress field at the lower surface of the dynamo layer at present precludes our deducing the entire dynamo layer winds from the observed Sq magnetic variation. The kinematics of the dynamo layer are discussed and the motion or the dynamo layer is divided into a symmetric and an antisymmetric part. The term symmetric is here used to describe winds in the northern and southern hemisphere that are the mirror images of each other with respect to the equatorial plane. It is demonstrated that the symmetric component gives rise to electrostatic fields transverse to the field lines, but to no currents along the field lines, while the antisymmetric case produces the converse effects. The symmetric and antisymmetric winds ape further divided into components according to the horizontal electromotive force they produce. (a) Symmetric Wind In the case of the symmetric wind, only the portion of the wind producing the solenoidal component of the horizontal dynamo electromotive force is effective in producing ionospheric currents. It is demonstrated that only this current producing wind system acts against the constraints imposed by the geomagnetic field on magnetospheric motions. The motion of the magnetospheric plasma driven by each such wind system is discussed. The earlier treatments of the dynamo theory consider the dynamo region to be a single layer in which the wind system and the electric conductivity are assumed to be uniform in height. A new, more general derivation of the layer's dynamo action is given in which no restrictions are placed upon the vertical distributions. An effective wind is defined which permits the use of the earlier equations relating the current function, the electrostatic field, and the scalar field describing the current producing part of the effective wind. The equation relating the electrostatic field and the current function is essentially that employed by Maeda (1956), allowing his solution for the portion of the electrostatic field associated with the current producing wind to remain unaffected by the stratification of the wind system. Mathematical techniques for solving the dynamo equations for the elecrostatic field are developed. These allow for a quite general conductivity distribution over the globe, only requiring that it be expressible in surface harmonics. The effect of undetected zonal currents upon the solution for the electrostatic field is discussed. It is suggested that a considerable diurnal component of electrostatic field and other components as well may be hidden from us by our inability to detect the prevailing magnetic perturbations produced by zonal currents. The electrostatic field associated with the non-current producing components of the symmetric wind is likewise hidden from us. (b) Antisymmetric Wind The equations for the current driven by the antisymmetric component of wind are derived, and some of the effects of such currents are discussed. It is found that the conduction of current along the field lines from one hemisphere to the other is associated with an interhemispheric stress between geomagneticaliy conjugate points of order 3 x 10⁻⁷ newtons/meter². In addition it is found that an antisymmetric layer current density of 5 amperes/km into the polar cap region (across the 75° latitude circle) might give rise to a displacement of about 150 km in the relative position of the conjugate points defined by field lines of the magnetospheric tail. It is suggested that the dynamo action in the 100 to 150 km height plays a role in determining the manner in which the magnetosphere divides itself into the corotating region and the magnetospheric tail.
    • Radiowave Scattering Structure In The Disturbed Auroral Ionosphere: Some Measured Properties

      Fremouw, Edward Joseph; Philip, K.; Parthasarathy, R.; Tryon, J.; Owren, L. (1966)
    • Noctilucent Clouds

      Fogle, Benson Tarrant; Chapman, Sydney; Rai, Dharmbir; Romick, Gerald; Haurwitz, Bernhard (1966)