Richard H. Stasiak

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Lotic systems within the Great Plains are characterized by highly fl uctuating conditions through both space and time. Fishes inhabiting these systems have adopted specifi c lifehistory strategies to survive in such environments; however, anthropogenic disturbance to prairie streams has resulted in declines and extirpation of many native stream fi shes.(More)
Two presumptive hybrid populations are examined. Nebraskan hybrids, all having allozymic F1 electromorphs, exist as both diploid (2n=50) and triploid (3n=75) forms. This supports the hypothesis of parthenogenesis as the mode of hybrid reproduction. The maximum number of nucleoli per cell is suggested as an indicator of ploidy level. In contrast,(More)
We chronicle the development of eggs stripped from a wild caught hybridPhoxinus eos x Phoxinus neogaeus, that were then mixed with sperm formPhoxinus eos. Approximately half the eggs died in development. It is hypothesized the dead embryos are the male sex, the postulated heterogametic sex. Egg hatching time approximated that ofneogaeus instead ofeos.(More)
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