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All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

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A Study Of Sedge-Dominated Areas In The Uinta Mountains, George Murchie Briggs May 1978

A Study Of Sedge-Dominated Areas In The Uinta Mountains, George Murchie Briggs

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Twenty-six sedge-dominated sites in the Uinta Mountains of northeastern Utah were studied. These sites could be placed into two categories, wetland sites (those with water-saturated soils) and alpine tundra sites.

The alpine sites had above-ground standing crops between 37 and 206 g/m2. The soils were sandy and low in nutrients. Indirect gradient analysis of the alpine sites showed a relationship between soil stability and vegetation. No other factors were found to be related to overall vegetation patterns.

The wetland sites were dominated by different Carex species than the alpine sites. These wetlands were often patches of monotypic stands. …


Analysis Of Ecosystem Models, Walter Dewey Valentine May 1978

Analysis Of Ecosystem Models, Walter Dewey Valentine

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Recent attempts to apply frequency response analysis to compartmental models of ecosystems are flawed by the failure to define terms in an unambiguous and ecologically meaningful way, and by the failure to distinguish between information feedback and closed material loops. Analysis of the sensitivity of linear models to changes in the A matrix has shortcomings too: elements of the A matrix are often derived from more fundamental parameters and thus do not have a direct relationship to the parent model; only sensitivities to the fundamental parameters will be unconfounded and readily interpretable. A more serious problem with these techniques is …


The Role Of Vegetation Architecture In Determining Spider Community Organization, Cynthia L. Hatley May 1978

The Role Of Vegetation Architecture In Determining Spider Community Organization, Cynthia L. Hatley

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The relationships between vegetation architecture and spider community attributes were examined in a big sage (Artemisia tridentata) community. Spiders were separated into guilds using similarities of species' hunting behavior. Shrub architecture was experimentally manipulated in the field by either clipping 50% of a shrub's foliage to decrease foliage density or tying together a shrub's branches to increase foliage density.

Temporal patterns of spider species density, diversity (H') and evenness (J') showed midsummer peaks in both 1974 and 1975. Seasonal spider guild trends reflected the temporal prominence of a member species or genus. These temporally abundant species appeared to …


Quantitation Of Formaldehyde Resulting From Oxidative Deterioration Of Unsaturated Fatty Acids, Stanley J. Andrews May 1978

Quantitation Of Formaldehyde Resulting From Oxidative Deterioration Of Unsaturated Fatty Acids, Stanley J. Andrews

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Derivatives of 3-methyl-1-2-benzothiazolinone hydrazone were formed from the oxidation products of three oxidized unsaturated fatty acids. Aeration with oxygen and heat (65C) was used as a means of accelerating deterioration of lipid samples. Formaldehyde was recovered from oxidized pure standards of oleic, linoleic and linolenic acid methyl esters, and identified using gas chromatography. Formaldehyde was also recovered from oxidized lipid extracts of mechanic ally deboned turkey meat and turkey cluster fat. Gas chromatography was used to measure concentrations of unsaturated fatty acids during the oxidation of extracted lipids. Linoleic and linolenic fatty acids significantly decreased (p < .005) in oxidized lipid extracts from turkey cluster fat stored frozen for six months.

Measurement of the amounts …


Biochemical Investigations Of Black Gram (Phaseolus Mungo L.) And Rice (Oryza Sativa L.) Proteins And Their Improved Nutritional Functionality In The Fermented Product—Idli, Vinodkumar W. Padhye May 1978

Biochemical Investigations Of Black Gram (Phaseolus Mungo L.) And Rice (Oryza Sativa L.) Proteins And Their Improved Nutritional Functionality In The Fermented Product—Idli, Vinodkumar W. Padhye

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The objectives of this investigation have been to characterize black gram (Phaseolus mungo L.) and rice (Oryza sativa L.) proteins and to study changes in their nutritional value due to fermentation. Black gram, the legume chosen for this work, is one of the most important legume crops throughout a large part of the tropics.

The protein content of 60 mesh, dehydrated, defatted black gram meal was 28.5 percent. Sodium carbonate (0.5-1.0 percent), tetra-sodium pyrophosphate (0.5 percent), and sodium dodecyl sulfate (SDS) (0.5-5 percent) proved to be the potential protein solubilizers as they extracted more than 76 grams of …


Influence Of Spring Sheep Grazing On The Forage Intake And Quality Of Diets Consumed By Pen-Reared Mule Deer Under Winter-Range Conditions, Kenneth Owen Fulgham May 1978

Influence Of Spring Sheep Grazing On The Forage Intake And Quality Of Diets Consumed By Pen-Reared Mule Deer Under Winter-Range Conditions, Kenneth Owen Fulgham

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study examined the nutritional responses of mule deer during winter on range subjected to a system of spring livestock grazing. The specific purposes were 1) to determine the quality (crude protein, digestible energy, and digestibility) of diets consumed by mule deer in winter on ranges grazed and ungrazed by sheep in spring, 2) to determine the level of forage intake, as determined by the external indicator chromic oxide, for deer under the same grazing regimes, 3) to compare forage intake estimates determined by the external indicator (chromic oxide) with results obtained by ocular estimation, and 4) to determine the …


Mathematical Equations Describing Chick Performance And Carcass Composition As A Function Of Diet Protein And Energy Levels, Naiyana Nakhata Jan 1978

Mathematical Equations Describing Chick Performance And Carcass Composition As A Function Of Diet Protein And Energy Levels, Naiyana Nakhata

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Previous work at Utah State University determined minimum levels of different nutrients that would produce the maximum rate of gain or gain/feed ratio by feeding graded levels of the nutrients. Fitting broken lines to the data from work with one nutrient tended to underestimate the minimum requirement for that nutrient. It appeared that the response was not linear up to the level required to give maximum performance as the "broken line" approach to estimating the requirement assumes. It seemed worthwhile to try to describe the relation between ration level of a nutrient and chick performance by means of a mathematical …


The Influence Of Various Factors On Nitrogen Balance And Protein Quality Measured In Adult Human Beings, Arthur John Wittwer May 1977

The Influence Of Various Factors On Nitrogen Balance And Protein Quality Measured In Adult Human Beings, Arthur John Wittwer

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of nitrogen intake, nitrogen source, calorie intake, body weight, adaptation time, research group and sex on the nitrogen balance of human adults was investigated. Data from studies reported in the literature were combined and analyzed statistically by multiple regression techniques. Analyses were made separately for six sources of nitrogen: egg, beef, rice, corn, wheat and wheat gluten.

Nitrogen intake, caloric intake and body weight exerted significant effects on nitrogen balance (5% level of confidence) for six, three and two of the six nitrogen sources, respectively. Other variables were not significant at the 5% level. Although differences were not …


In Vitro Morphogenesis And Mutation Of Glycine Max L., Thomas Daniel Wilson May 1977

In Vitro Morphogenesis And Mutation Of Glycine Max L., Thomas Daniel Wilson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Soybean (Glycine max L. c.v. Consoy) tissue cultures were grown in synthetic media containing various concentrations and combinations of minerals, auxins, cytokinins, pH levels, and inorganic growth factors in a systematic procedure to establish optimum media for initiation and maintenance of callus. Further modification of the hormone level was employed to initiate callus morphogenesis. Normally toxic levels of atrazine were established in soybean calli media, and ethyl methanesulfonate (EMS) and X ray-induced mutant calli were selected for atrazine tolerance.

Optimal media for initiation and maintenance of soybean calli were developed and a defined medium was determined that consistently yields …


A Preliminary Investigation Of The Lipid Of Halophilic Bacteria As A Food Additive, Neil F. Collins May 1977

A Preliminary Investigation Of The Lipid Of Halophilic Bacteria As A Food Additive, Neil F. Collins

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was conducted to evaluate the feasibility of obtaining workable quantities of the unusual ether-linked phosphatidyl glycerophosphate of halophilic bacteria through batch culture of Halobacterium halobium. Once isolated and purified, physical, emulsification, and toxicological properties of the lipid were evaluated with respect to its use as a nonnutritive lipid substitute or an emulsifier by the food industry. These evaluations included physical descriptions, melting properties, hydrophile-lipophile balance (HLB) determination, and oral and intraperitoneal administration of the lipid to laboratory mice.


Fine Structural Aspects Of The Developing Eye Of The Honey Bee, Judith Susan Eisen May 1977

Fine Structural Aspects Of The Developing Eye Of The Honey Bee, Judith Susan Eisen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The post-embryonic development of the compound eye of the worker honey bee was investigated with the light and electron microscopes. The cells of the optic primordium were reorganized into preommatidial cell clusters during the late third and early fourth larval instars. Each cluster contained nine prospective retinula cells, the ninth was centrally located and shorter than the other eight; four prospective cone cells; and an undetennined number of prospective pigment cells.

Rhabdomere development began in the eight peripherally located retinula cells just prior to pupation. Following pupation, each ommatidium elongated. During ommatidial elongation, the short ninth retinula cell moved from …


Nitrogen Fixation, Ammonification, Denitrification In Great Basin Arid Soils, Brian Paul Klubek May 1977

Nitrogen Fixation, Ammonification, Denitrification In Great Basin Arid Soils, Brian Paul Klubek

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The inputs and losses of nitrogen from Great Basin arid soils were studied using the acetylene reduction and 15N techniques. Filamentous blue-green algae were observed to be the predominant algal group in the soil crusts. The bacterial association with this group of algae suggest a phycosphere-like effect, thus allowing heterotrophic nitrogen fixation and denitrification to occur. Up to 17.5 mg N/100 g soil was found to have been fixed in surface soils (0 to 3 cm) during a three week incubation period, while 45.9 mg N/100 g soil was fixed in a five-week incubation period. Ammonium sulfate and ammonium …


Density And Diversity Responses Of Summer Bird Populations To The Structure Of Aspen And Spruce-Fir Communities On The Wasatch Plateau, Utah, Janet Lee Young May 1977

Density And Diversity Responses Of Summer Bird Populations To The Structure Of Aspen And Spruce-Fir Communities On The Wasatch Plateau, Utah, Janet Lee Young

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Sixteen stands representing a range of structural variation in aspen, mixed aspen-conifer, and spruce-fir communities of the Wasatch Plateau, Utah, were censused by the sample count method. The stands were classified as eleven community types based on the understory dominants or indicator species and the cover types. Fifty bird species were recorded during the two seasons; thirty-two occurred in aspen cover, forty-four in mixed aspen-conifer cover, and twenty-two in spruce-fir.

Comparisons of the composition and density of bird populations were made between uniform stands of a single life form and more structurally complex stands of either single or mixed life …


Chemical Quality Variation In A Small Mountain Watershed, David C. White May 1977

Chemical Quality Variation In A Small Mountain Watershed, David C. White

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to quantify the chemical nature of the Chicken Creek waters, and to investigate the variability and causes of that observed chemistry. The three objectives of the study were: 1) inventory the chemistry of the water produced by the subject watersheds, 2) determine chemical budgets for the watersheds, and 3) identify the sources of the primary chemical components.

Chemical surveys were made: 1) on the stream exiting from each gaged watershed, 2) at various points within the West Branch drainage network, 3) of the atmospheric inputs (rain, snow, and dust), 4) of the soil solution, …


Consumption, Digestion, And Utilization By Goats Of The Dry Matter And Nitrogen In Diets Containing Oak (Quercus Gambelii) Foliage, Anastasios Stefanos Nastis May 1977

Consumption, Digestion, And Utilization By Goats Of The Dry Matter And Nitrogen In Diets Containing Oak (Quercus Gambelii) Foliage, Anastasios Stefanos Nastis

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Part I
A study of animal performance was made with goats fed, ad libitum ground and pe11eted mixtures of Gambe1 oak and alfalfa. Intake, digestibility, metabolizable nitrogen, and metabolized energy of oak diets were generally lower than those for a control alfalfa diet. However, no significant differences in live weight gains of experimental animals were found. No apparent toxicity was detected in goats fed diets containing up to 80 percent oak for 72 days.

Part II
Mixtures of oak (Quercus gambelii) and alfalfa (Medicago sativa) were used to evaluate three laboratory techniques, the Tilley and Terry …


Autoecology Of The Ruderal Weed Heterotheca Grandiflora With Emphasis On Germination Dimorphism, Stephan Dexter Flint May 1977

Autoecology Of The Ruderal Weed Heterotheca Grandiflora With Emphasis On Germination Dimorphism, Stephan Dexter Flint

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Weedy species, as they occupy diverse and unpredictable environments, are expected to possess considerable variability in numerous characteristics, including germination. The visually dimorphic achenes of Heterotheca grandiflora Nutt. (Asteraceae) were tested for potentially adaptive differences in their germination, the establishment of the resulting seedlings, and the relative production of the two achene types.

Achenes produced by the disc florets are adapted for dispersal and rapid germination while the ray florets produce smaller achenes lacking a dispersal mechanism, but possessing a more sophisticated physiological system capable of regulating germination. Ray achene germination rates were significantly influenced by different soil surfaces while …


Two Generational Study On The Effect Of Different Levels Of Fluoride On Rat Bone And Teeth, Madhav Prasad Upadhyay May 1977

Two Generational Study On The Effect Of Different Levels Of Fluoride On Rat Bone And Teeth, Madhav Prasad Upadhyay

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effects of different levels of fluoride in drinking water on different parameters of femurs and incisors of female rats were studied. Rats and their offspring, before and after weaning, were used for the study. Mother rats received 0, 1 and 5 ppm fluoride in drinking water. After weaning, the offspring were given the following treatments: 0-0, 0-1, 0-5, 1-0, 1-1, 1-5, 5-0, 5-1 and 5-5; the first number indicating fluoride level of mother's water during mating, pregnancy and lactation and the second number indicating the fluoride level of water given to the offspring. Femurs and top and bottom incisors …


A Process Incorporating Ultrafiltration Concentrated Whey Solids Into Cheese For Increased Cheese Yield, Rodney Jay Brown May 1977

A Process Incorporating Ultrafiltration Concentrated Whey Solids Into Cheese For Increased Cheese Yield, Rodney Jay Brown

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A process which incorporates whey sol ids, primarily protein, into cheese to increase cheese yield and eliminate whey handling problems was evaluated. Whey was concentrated by ultrafiltration to levels of 9.8 to 20.3 percent total solids (4.3 to 7.1 percent protein), heated at 70 C for 30 minutes and added to cheese milk with the coagulating enzyme.

Increase in cheese yield, on the basis of 39 percent moisture, for 10 pairs of samples was 4.0 ± 2.8 (S.D.) percent. This increase was significant at alpha less than 0.001. Moisture and protein content increased while fat content decreased. Setting time and …


The Impact Of Pesticides On The White-Faced Ibis, David E. Capen May 1977

The Impact Of Pesticides On The White-Faced Ibis, David E. Capen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The white-faced ibis (Plegadis chihi) which nested in northern Utah was assessed as a species with a relatively low reproductive potential. Ibises normally laid either three or four eggs in a clutch and did not renest persistently, nor with good success, if initial nesting attempts failed. Evidence indicated that the birds did not breed until at least 2 years old. Competition for food, exposure to severe weather, and predation were conspicuous sources of nestling mortality. White-faced ibises usually fed in irrigated agricultural areas, where they came into direct contact with insecticides, such as DDT which was used routinely …


Plant Material Information Needs Of Landscape Architects And Horticulturists In The Intermountain Region, Kenneth Raleigh Brooks May 1977

Plant Material Information Needs Of Landscape Architects And Horticulturists In The Intermountain Region, Kenneth Raleigh Brooks

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The landscape plant materials informational needs of planting designers were evaluated in a historical and contemporary context. It was found that plant designers need to know about the environmental and cultural adaptation, landscape value and use, and commercial availability of the plant materials that they use.

Surveys of regional plant materials experts and nursery inventories were made to determine which plants should be included in a reference text. The climate of the region is also identified and compared to other parts of the country.

Plant materials reference books were reviewed to see if they provided this information for plants grown …


Effects Of Low-Level Chronic Radiation On Plant Nuclear Parameters As Related To Successional Patterns, Eric A. Rechel May 1977

Effects Of Low-Level Chronic Radiation On Plant Nuclear Parameters As Related To Successional Patterns, Eric A. Rechel

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

A major issue facing nuclear power stations is how to effectively deal with radioactive waste. This waste, as it comes from a reactor, is emitting large quantities of ionizing radiation which is usually confined. Another form of radioactive wastes is the mill tailings from uranium processing plants. These tailings are sites characterized by low-level chronic radiation.

The mill tailings of the Vitro Chemical Plant, in Salt Lake City, Utah, have been a point of radionuclide concentration and environmental contamination for 20 years. These tailings may adversely affect both surrounding ecosystems and any biological systems seeking to become established on the …


Maternal Reactions To Children With Visible And Non-Visible Handicaps, Doral R. Olsen May 1977

Maternal Reactions To Children With Visible And Non-Visible Handicaps, Doral R. Olsen

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The purpose of this study was to investigate the reactions of mothers to their handicapped child to determine if there is an association between visible and non-visible handicaps, and the mother's reaction to the handicapped child.

A null hypothesis was employed which asserted that the mother's reaction to the handicapped child would not be related to the visible nature of the handicap. It was further hypothesized that the variables of mother's age at the birth of the handicapped child, education, and rigidity, child's birth order and the husband's occupation would be unrelated to the mother's reaction to her child

The …


The Effects Of Campgrounds On Small Mammals In Canyonlands And Arches National Parks, Utah, Gregory A. Clevenger May 1977

The Effects Of Campgrounds On Small Mammals In Canyonlands And Arches National Parks, Utah, Gregory A. Clevenger

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Campground use in our national parks is increasing yearly, but little quantitative data are available concerning the impact this use is having on the ecology of the campground and surrounding area. This paper reports on some of the effects of campgrounds on small mammal populations in Canyonlands and Arches National Parks, Utah. Data collection consisted of live-trapping from April to November, 1975 (12,337 trap-nights). The populations of Ordls kangaroo rat (Dipodomys ordii), antelope ground squirrels (Ammospermophilus leucurus), deer mice (Peromyscus spp.), woodrats (Neotoma spp.), Colorado chipmunks (Eutamias guadrivittatus), and desert …


Relationships Of Vegetation To Environment In Canyonlands National Park, Walter Lee Loope May 1977

Relationships Of Vegetation To Environment In Canyonlands National Park, Walter Lee Loope

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The vegetation of Canyonlands National Park, Utah, has been described from 157 samples located throughout the Park. Species frequency, density and cover were recorded along with measurements of soil thickness, slope, aspect, elevation and geologic substrate at each site. Measurements of soil texture, pH, and electrical conductivity were taken for a representative subsample. A map of the vegetation of the Park was made by relating the sample points to their corresponding spectral signatures on vertical aerial photographs and locating boundaries between vegetation units by means of changes in photo signatures.

Vegetation in these arid to semi-arid environments appears to be …


Distribution And Habitat Characteristics Of The Kit Fox (Vulpes Macrotis) In Utah, John C. Mcgrew May 1977

Distribution And Habitat Characteristics Of The Kit Fox (Vulpes Macrotis) In Utah, John C. Mcgrew

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The distribution of the kit fox (Vulpes macrotis) in Utah was studied from 1974 to 1976. A variety of methods were used, but a questionnaire sent annually to state and federal agencies, combined with interviews of field personnel of these agencies, was found to be the most valuable. Kit foxes occur in western Utah and Washington County as previously reported. In addition, range extensions were noted in central Utah, and in Carbon, Emery, Grand, Wayne, and Garfield counties in east-central Utah. These range extensions total approximately 4,600-square miles (12,000-square kilometers). The kit fox probably also inhabits San Juan …


Spawning Biology Of Channel Catfish Ictalurus Punctatus (Rafinesque) In Willard Bay Reservoir, Utah, Stuart Terry Shipman May 1977

Spawning Biology Of Channel Catfish Ictalurus Punctatus (Rafinesque) In Willard Bay Reservoir, Utah, Stuart Terry Shipman

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study was conducted on Willard Bay Reservoir, Utah, during the summers of 1972 and 1973, to study the spawning biology of the channel catfish (Ictalurus Punctatus), and to evaluate potential reproduction for this species in the reservoir. Potential reproduction was evaluated through examination of available natural habitat and use of artificial habitat provided for this study.

Channel catfish were found to mature by the end of their fourth year and spawn from mid-June through August. A total of 12 nesting channel catfish were observed along 15, 0.8 kilometer (0.5 mile) sections of dike. Ten of these 12 …


Rodent Density And Species Composition In The Snake River Birds Of Prey Natural Area, Idaho, Jon R. Montan Jr. May 1977

Rodent Density And Species Composition In The Snake River Birds Of Prey Natural Area, Idaho, Jon R. Montan Jr.

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Rodent densities were estimated in the major vegetation types of the Snake River Birds of Prey Natural Area in 1975 and 1976 by a combination of live-trapping and kill-trapping. Only deer mice (Peromyscus maniculatus) were numerous enough to permit reliable density estimates. Relative densities of other rodent species were indicated by kill-trap capture rates. Densities of deer mice correlated well (r = 0.99) with kill-trap capture rates. The use of kill-trapping in place of live-trapping in 1976 permitted extensive sampling throughout the 1930 km2 study area. Differences were found among the major vegetation and land-use types in …


Household Projections For Utah: 1970-2000, Stephen Hauwah Kan May 1977

Household Projections For Utah: 1970-2000, Stephen Hauwah Kan

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

This study deals with Utah household projections by age and sex for five-year intervals from 1970-2000. Projections are based on the method used by the bureau of the Census with certain modifications. Two sets of the population projects prepared by the Utah Agricultural Experiment Station, high and low medium, are chosen as the population base. By assuming the household formation pattern in two alternate ways, constant rates and exponential growth rates, two sets of household projections are prepared for each of the two sets of population projections. This study also makes some examinations on the social and economic implications of …


Subtle Teratogenic Effects Of Locoweed In Rats, Benjamin K. Nelson May 1977

Subtle Teratogenic Effects Of Locoweed In Rats, Benjamin K. Nelson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Locoweed, a well-known teratogenic plant affecting livestock, is prevalent in mountain regions of the Western United States. Two common species (Astragalus lentiginosus and A. wootoni), administered to pregnant rats, induced behavioral deviations in their offspring. Treated mothers consumed less feed and gained less wieght during gestation than controls when gavaged locoweed at the rate of 1 gram whole plant per day on days 7 through 17 of gestation. A. lentiginosus reduced pup weight at birth (13% less than controls) and this weight reduction (as much as 29% less than controls) continued at least four weeks. A. lentiginosus also …


Aspects Of The Life History Of Three Catostomids Native To The Upper Colorado River Basin, Charles W. Mcada May 1977

Aspects Of The Life History Of Three Catostomids Native To The Upper Colorado River Basin, Charles W. Mcada

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The distribution, abundance and life history were studied for three catostomids -- the razorback sucker (Xyrauchen texanus), the flannel-mouth sucker (Catostomus latipinnis), and the bluehead sucker (Catostomus discobolus) -- all native to the upper Colorado River basin. The razorback sucker has declined in abundance due to man's impact upon the system and it has been recommended that this species be listed as ''threatened" on the U. S. Department of the Interior's list of Threatened or Endangered species [Personal corrmunication, G. C. Kobetich, U. S. Fish and Wildlife Service, Las Vegas, Nevada]. During this investigation, …