Thesis (M.S.)--North Carolina State University, 2003. / Title from PDF t.p. (viewed on Dec. 8, 2005). Vita. Includes bibliographical references (p. 97-103).

In 1961 the Green River was poisoned and its native fishes killed so that the new Flaming Gorge Reservoir could be stocked with non-native game fishes for sportsmen. This incident was representative of water management in the West, where dams and other projects have been built to serve human needs without consideration for the effects of water diversion or depletion on the ecosystem. Indeed, it took a Supreme Court decision in 1976 to save Devils Hole pupfish from habitat destruction at the hands of developers. Nearly a third of the native fish fauna of North America lives in the arid West; this book traces their decline toward extinction as a result of human interference and the threat to their genetic diversity posed by decreases in their populations. What can be done to slow or end this tragedy? As the most comprehensive treatment ever attempted on the subject, Battle Against Extinction shows how conservation efforts have been or can be used to reverse these trends. In covering fishes in arid lands west of the Mississippi Valley, the contributors provide a species by species appraisal of their status and potential for recovery, bringing together in one volume nearly all the scattered literature on western fishes to produce a monumental work in conservation biology. They also ponder ethical considerations related to the issue, ask why conservation efforts have not proceeded at a proper pace, and suggest how native fish protection relates to other aspects of biodiversity planetwide. Their insights will allow scientific and public agencies to evaluate future management of these animal population and will offer additional guidance for those active in water rights and conservation biology.

D.Phil.

The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Title from PDF of title page (University of Missouri--Columbia, viewed on October 6, 2009). Thesis advisor: Dr. Douglas B. Noltie. Includes bibliographical references.

The goal of this research was to develop captive propagation methods for the Federally threatened spotfin chub, Cyprinella monacha, and yellowfin madtom, Noturus flavipinnis, by using closely related, but unthreatened species, to evaluate potential techniques. The surrogate species used were the whitetail shiner, Cyprinella galactura, and the margined madtom, Noturus insignis. I investigated methods to promote gonadal maturation, induce spawning, and rear larvae of these fishes. Captive whitetail shiners developed mature gonads under a variety of temperature and photoperiod conditions. Spawning condition was maintained for over two years when they were held at constant warm temperature (≈ 24 C) and long photoperiod (16 h light). Whitetail shiners did not readily spawn in aquaria, but were induced to spawn by hormonal injection with human chorionic gonadotropin (hCG) and carp pituitary extract (CPE) at mean dosages of 1688 I.U./kg and 20 mg/kg, respectively, or with luteinizing hormone releasing hormone analogue (LHRHa) and domperidone at mean dosages of 363 µg/kg and 36 mg/kg, respectively. Most females spawned within 30 h of the first injection. Stripped ova were effectively wet-spawned, and larvae hatched in 8 d at 25 C. I obtained a mean hatch rate of 55 %, but lack of swimbladder inflation resulted in very poor survival of several batches of eggs. Larvae began feeding within 2 d of hatching, and survival rates of 50 to 90 % after 16 d were obtained when larvae were fed twice daily on a diet of brine shrimp nauplii at a rate of ≈ 10/L/d, and a commercially prepared larval fish diet at a rate of ≈ 14 mg/L/d. Changing photoperiod, but not temperature, was required to induce oocyte maturation in most captive female margined madtoms. Sperm production in mature male madtoms was enigmatic; motile sperm were observed only once. Plasma testosterone concentrations in males peaked just prior to the spawning season at 6.5 ng/mL, but levels were not correlated with male gonadosomatic values. Plasma 17β-estradiol levels in females peaked just prior to the spawning season at 15 ng/mL, and were correlated with gonadosomatic values. Captive margined madtoms did not tank spawn unless they were hormonally injected with hCG and CPE at mean dosages of 5256 I.U./kg and 58 mg/kg, respectively, or with LHRHa and domperidone at mean dosages of 554 µg/kg and 55 mg/kg, respectively. Most females ovulated within 78 h of the first injection. Inclusion of more than one breeding pair per tank inhibited tank spawning. Embryos did not develop in 55 % of tank-spawned ova, or from any strip-spawned ova. Parents consumed spawned egg masses if they remained with the nest. Hatch rates > 65 % were obtained by suspending egg masses in a large-mesh basket over turbulent aeration at 28 to 30 C. Larvae hatched in 7 d at 28 C. Survival rates > 50 % after 15 d were obtained when larvae were fed salmon starter twice daily at a rate of 20 mg/L/d, and tanks were thoroughly cleaned daily. / Ph. D.