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Fish habitat degradation in U.S. reservoirs

Fish habitat degradation in U.S. reservoirs. Presented by Rebecca M. Krogman Department of Wildlife, Fisheries and Aquaculture Mississippi State University. Acknowledgments. L. E. (Steve) Miranda Mississippi Cooperative Fish and Wildlife Research Unit

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Fish habitat degradation in U.S. reservoirs

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  1. Fish habitat degradation in U.S. reservoirs Presented by Rebecca M. Krogman Department of Wildlife, Fisheries and Aquaculture Mississippi State University

  2. Acknowledgments • L. E. (Steve) MirandaMississippi Cooperative Fish and Wildlife Research Unit • W. Reed GreenUSGS Arkansas Water Science Center • Kirk RodgersPh.D. Student, University of Arkansas – Little Rock • Many, many state fisheries biologists! • Jeff BoxruckerRFHP Science & Data Committee Chair, Oklahoma Department of Wildlife Conservation (recently retired) • And everyone else at the Reservoir Fisheries Habitat Partnership! • Funding provided by U.S. Fish and Wildlife Service

  3. Introduction

  4. Construction of large reservoirs

  5. Construction of large reservoirs • “I think we all agree that the construction of reservoirs has been the greatest single contribution in this century to sport fishing and other forms of outdoor recreation.” • - Brigadier General H. G. Woodbury, Jr., US Army Corps of Engineers

  6. Large reservoirs (>250 acres) National Inventory of Dams 2009

  7. Comparison to natural lakes • Top in purple: Lake Itasca watershed • Bottom corner: Pool 2 of the Mississippi River Credit: Minnesota Pollution Control Agency

  8. Comparison to natural lakes

  9. Fish habitat issues Delta behind Matilija Dam, California

  10. Effects on fisheries • Habitat availability • Oxygen • Structure • Connectivity • Spawning success • Change water levels • Substrate composition (e.g., gravel beds) • Siltation • Littoral zone vegetation and structure

  11. Effects on fisheries • Larval fish and fingerling survival • Food acquisition • Refuge from predation • Fish productivity • Nutrient dynamics • Availability of zooplankton and macroinvertebrates • Turbidity

  12. Main points • Reservoirs are numerous and ubiquitous • Reservoirs are a product of public policy • Reservoirs are aging • Habitat degradation can affect recreational fisheries

  13. Importance

  14. Reservoir Habitat Survey #1 Objective: To document the extent of habitat degradation in reservoirs in the U.S.

  15. Methods

  16. Variables • Suspended sediments or inorganic turbidity • Sedimentation • Shoreline erosion • Excessive nutrients • Point-source pollution • Contaminants • Oxygen or temperature stratification • Mistimed water level fluctuations • Insufficient water storage • Excessive aquatic macrophytes • Lack of aquatic macrophytes • Lack or loss of woody debris • Disconnectivity with backwaters • Invasive plant species

  17. Data Analysis • Factor analysis • Interpretation of primary factors and spatial variation • Development of Index of Reservoir Habitat Impairment (IRHI) • 221 respondents  494 waterbodies

  18. Results

  19. Data Analysis

  20. Data Analysis

  21. Spatial Variations

  22. Spatial Variations

  23. Spatial Variations

  24. Spatial Variations

  25. Spatial Variations

  26. New questions • What specific variables are important in each reservoir group? • How can we determine these reservoir groups? • How much of what we see is natural variation?

  27. Reservoir Habitat Survey #2

  28. Reservoirs as part of the landscape “In every respect, the valley rules the stream.” - H. B. N. Hynes, 1975 reservoir

  29. Objective 1 WWF Aquatic Ecoregions • Cluster analysis • Compare clusters to existing classification systems •  reservoir classes Develop a classification system for large U.S. reservoirs using impairment factors

  30. Objective 2 • Discriminant analysis • Empirical data • Basin characteristics • Local watershed characteristics • In-reservoir characteristics Validate the classification system using empirical factors

  31. Objective 3 • Ordination techniques to identify reservoirs with a high quality recreational fishery and good habitat • Predictive model development based on high-quality fishing reservoirs Develop a predictive model that assesses fish habitat impairment for each reservoir class

  32. Siltation Excessive suspended sediments or inorganic turbidity Sedimentation Shoreline erosion

  33. Potential Applications • Make quantitative comparisons among reservoirs • Understand geospatial relationships • Guide the decision-making process Fishing below J.T. Meyers Dam

  34. Questions or comments? To learn more about Survey #1 Miranda et al. 2010. Fish habitat degradation in U.S. reservoirs. Fisheries 35(4):175-184. Miranda and Hunt. 2010. An index of reservoir habitat impairment. Environmental Monitoring and Assessment. Published online. In press Hoover Dam.

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