京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第18185号 / 医科博第50号 / 新制||医科||4(附属図書館) / 31043 / 京都大学大学院医学研究科医科学専攻 / (主査)教授 朝長 啓造, 教授 松岡 雅雄, 教授 小柳 義夫 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

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Recently, examination of deoxyribonucleic acids in water samples (environmental DNA or eDNA) has shown promise for identifying fish species present in water bodies. In water, eDNA arises from bodily secretions such as mucus, gametes, and feces. I investigated whether eDNA can be effective for characterizing fish presence, relative abundance, biomass, and species composition in a large Arizona reservoir (Theodore Roosevelt Lake) and 12 small Arizona (<24 ha) waterbodies. Specifically, I compared fish presence, relative abundance (catch per unit effort [CPUE]), biomass (biomass per unit effort [BPUE]), and species composition measured through eDNA methods and established American Fisheries Society (AFS) standard sampling methods in Theodore Roosevelt Lake and 12 small waterbodies. Environmental DNA sampling resulted in detection of Gizzard Shad Dorosoma cepedianum at a higher percentage of sites than boat electrofishing, both in spring and fall. Contrarily, gill nets detected Gizzard Shad at more sites than eDNA for both spring and fall sampling in Lake Roosevelt. Boat electrofishing and gill netting detected Largemouth Bass Micropterus salmoides at more sites than eDNA, with the exception of fall gill net sites which equally detected Largemouth Bass at sites within Lake Roosevelt. Environmental DNA detected Largemouth Bass and Bluegill Lepomis macrochirus at more Arizona small lakes than detection with established gear methods. I observed no relationship between relative abundance and biomass of Largemouth Bass and Gizzard Shad measured by established methods and their DNA copies at individual sites or by lake section in Lake Roosevelt. Likewise, I found no relationship between relative abundance and biomass of Largemouth Bass and Bluegill measured by established methods and their DNA copies across 12 small waterbodies. Plot analysis conceivably illustrated that reservoir-wide catch composition (numbers and total weight of fish [g]) achieved through a combination of gear types (boat electrofishing + gill netting) for Largemouth Bass and Gizzard Shad was slightly similar to the proportion of total eDNA copies of each species for both spring and fall field sampling. Likewise, spring and fall gill net surveys somewhat portrayed total catch composition (numbers and total weight of fish [g]) of Largemouth Bass and Gizzard Shad similar to the proportion of total eDNA copies of each species. The exception was the total lack of similarity illustrated between proportions of fish caught in spring and fall boat electrofishing and total eDNA copies of each species in Lake Roosevelt. However, the deceptive similarity of all the plots were not present in the chi-square analysis with the exception of fall gill net surveys in Lake Roosevelt. In addition, eDNA did reflect the relative proportions of Largemouth Bass and Bluegill in total catch composition in some, but not all of 12 small Arizona waterbodies. The ease of eDNA sampling over established fish sampling makes it appealing to natural resource managers. Compared to current established fish sampling methods, eDNA sampling can be less laborious, less time consuming, and more cost effective. Environmental DNA sampling may be useful in sites that have difficult access such as remote sites. However, evaluation of eDNA is necessary to identify limitations and benefits in fish monitoring programs. Furthermore, field sampling protocols, filtration, DNA extraction, primer design, and DNA sequencing methods need further refinement and testing before incorporation into standard fish sampling surveys.

The topic of this thesis is the value of a selected natural resource and its influence on the region{\crq}s development. This thesis has been divided in two parts. The first part is theoretical and it defines natural resources and their evaluation. The theoretical part is concluded by information about regional politics and development. The practical part of this thesis consists of two areas. In the first one, I characterize South Bohemian region as well as Lipno reservoir. In the second one, I deal with the land prices in Lipno area and compare them to the land prices in the area around Orlik reservoir. The amount of the prices indicates differences in holiday resort values of these reservoirs and their contribution to the region{\crq}s development. The main goal of this work is to analyze, on the basis of natural resources{\crq} evaluation, the relationship between the natural resource value and economic development of the selected area of the South Bohemian region. Another significant goal is an elaboration of a survey of methods used in natural resources{\crq} evaluation, from the perspective of nonmarketable resources{\crq} evaluation as well as evaluation of any inmovable object that satisfies people{\crq}s needs. An important aim of the practical part of this thesis is a land price analysis of Lipno reservoir area. The last goal I have proposed to me is to compare the land prices around Lipno reservoir to those of Orlik reservoir. The value of an natural resource can be expressed in different ways, for example, in how much people, who use that holiday resort, esteem it. Considering the topic of my thesis, I have chosen an evaluation according to land prices. If a natural resource is valuable, then its value will be reflected in people{\crq}s willingness to pay for the possibility of living in its nearness. This is also obvious with Lipno reservoir, as the land prices there are much higher than the land prices in any other holiday resort situated near a water reservoir. Nevertheless, even here we can still find places, that have not been fully developped yet and which offer possibities of exploitation. Considering the above-mentioned findings and examples, it is obvious that Lipno water reservoir not only provides the South Bohemian region with incomes from tourisms but it also has a movable value of an ascending tendency. Despite its invaried long-time exploitation potential, its holiday resort function has caused recently, that Lipno area is being valued more and more. This tendency is reflected in the increasing prices of building estates near the reservoir, which indicates people{\crq}s willingness to pay more and more for a valuable holiday resource.

This study was designed to determine if impingement and entrainment by cooling water intake at the Comanche Peak Steam Electric Station have an adverse impact upon the Squaw Creek Reservoir fish population. The yearly impingement of fish was estimated to be 262,994 of 14 species. The threadfin shad (Dorosoma petenense) accounted for 96% of this total. Entrainment of eggs and larvae for a five month period was estimated to be 15,989,987 and 42,448,794 respectively. Two fish population studies were performed on Squaw Creek Reservoir to help assess impact. It was determined that the losses due to impingement and entrainment have no adverse impact upon the fish population of Squaw Creek Reservoir.