Spawning Early Life Stages And Early Life Histories Of The Osmerids Found In The Sacramento San Joaquin Delta Of California

Author : Sara Elizabeth Seidel
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (462 download)

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Download or read book Exploring the Spawning Dynamics and Identifying Limitations to the Early-life History Survival of an Important, Endemic Fish Species written by Sara Elizabeth Seidel and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: For many native, imperiled salmonid species, the prioritization of recovery and conservation efforts hinges upon the identification of a species most limiting life stage. The early life-history stage can be a limiting life stage for fish, and given the importance of the reproductive stage to overall persistence, there is a need to better understand the spawning ecology and early life history of many salmonids. The Logan River, in northern Utah, contains one of the largest metapopulations of imperiled Bonneville cutthroat trout (BCT) throughout the Bonneville Basin. LIttle research has evaluated the temporal and spatial distribution of BCT spawning nor quantified their early life-history survival. In the summer of 2009, I documented the spawning ecology of BCT and quantified their early life-history survival via egg-to-fry survival field experiments in four tributaries to the Logan River. I observed considerable variability in the timing, magnitude, and duration of spawning between study streams, in part as a function of a variable, multi-peaked hydrograph. I also conducted egg-to-fry survival experiments using incubation boxes and hatchery-fertilized, eyed cutthroat embryos and installed these boxes throughout my study streams. I found that survival was extremely variable within and among my study streams. For example, the variation I observed in survival appeared to be a function of fine sediment loads. Lastly, I observed that in the Logan River the timing of greatest intensity of both stream side and in-stream anthropogenic activities (e.g., livestock grazing, horseback riding) overlaps directly with the spawning and early life stages of BCT. Using my estimates of early survival, I revised a four-stage matrix population model for BCT in order to evaluate the hypothetical effects of anthropogenic impact on rearing areas. I determine that population growth rates are sensitive to perturbation at the egg-to-fry and fry to age-1 stages, and if even a small number of redds are destroyed through habitat degradation, a high degree of immigration of reproductivityly mature BCT is required to maintain the near-term persistence of this population. Future conservation efforts for BCT should be prioritized to protect areas where land-use activities are high during the sensitive spawning and early life-stage periods.