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Dave Bartz, WI DNR Fisheries Biologist, Green Lake Fish Survey 2011


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Big Green Lake underwent a comprehensive fish survey beginning in spring 2011. At the 2011 GLA Annual Meeting, guest presenter Dave Bartz, WI DNR Fisheries Biologist, shared sampling techniques for collecting data on different fish species and also shared what information he hopes to gather during the survey.

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Dave Bartz, WI DNR Fisheries Biologist, Green Lake Fish Survey 2011

  1. 1. Big Green Lake Fish Survey - 2011
  2. 2. Objectives <ul><li>Sample Coolwater Fisheries </li></ul><ul><ul><li>Spring Fyke netting and Electrofishing </li></ul></ul><ul><ul><ul><li>Walleye, Northern Pike, Bass sp. and panfish </li></ul></ul></ul><ul><ul><ul><ul><li>Catch Rates/Population Density </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Population Age Structure and Growth Rates </li></ul></ul></ul></ul><ul><ul><li>Fall Electrofishing </li></ul></ul><ul><ul><ul><li>Walleye Recruitment </li></ul></ul></ul><ul><li>Sample Coldwater Fisheries </li></ul><ul><ul><li>Fall Gill Netting, Fyke Netting and Shocking </li></ul></ul><ul><ul><ul><li>Lake Trout, Brown Trout and Cisco </li></ul></ul></ul><ul><ul><ul><ul><li>Catch Rates/Population Density </li></ul></ul></ul></ul><ul><li>Carp? </li></ul>
  3. 3. Fyke Net Lead
  4. 4. Set Fyke Net
  5. 5. Set Net ready to run
  6. 6. Sex determination on Northern Pike
  7. 7. All fish sexed and measured to nearest tenth of an inch Weights and age samples taken on subsample
  8. 8. Green Lake Musky 2500 stocked annually since 2004
  9. 9. Black Crappie
  10. 14. Boomshocker
  11. 15. Age Structures Dorsal Spines Scales
  12. 19. Walleye - 94 survey <ul><li>Low density population </li></ul><ul><li>Recruitment problems </li></ul><ul><ul><li>habitat loss </li></ul></ul><ul><ul><li>predation/competition </li></ul></ul><ul><ul><li>cool water temperatures </li></ul></ul><ul><li>Increased interest in stocking </li></ul><ul><li>Concern over genetics </li></ul>
  13. 21. Mixing OTC Solution for marking fry
  14. 22. Gill Netting <ul><li>Net locations are historical sites </li></ul><ul><li>Target species are Lake Trout and Cisco </li></ul><ul><ul><li>Catch rate comparisons </li></ul></ul><ul><ul><li>Size structure comparisons </li></ul></ul><ul><ul><li>New aging techniques </li></ul></ul>
  15. 25. Stocking 1980-Present <ul><li>Quotas increased 1980-82 </li></ul><ul><li>Increased recruitment by 1984 </li></ul><ul><li>Disease problems 1987-89 - No stocking </li></ul><ul><li>Stocking quotas raised to 50,000 in 1991 </li></ul><ul><li>Presently quotas back to 25,000 </li></ul><ul><li>Average 30,736 since 1992 </li></ul><ul><li>VHS concerns have affected availability </li></ul>
  16. 30. Cisco
  17. 32. Seeforellen Brown Trout
  18. 34. Carp <ul><li>First planted in 1882 </li></ul><ul><li>Full scale removal efforts by 1930’s </li></ul><ul><li>Carp trap at County A in 1950’s-60’s </li></ul><ul><li>State rough fish crews 1950’s-60’s </li></ul><ul><li>Commercial removal during the 80’s </li></ul><ul><li>Carp trap at County K – 1992 replaced by barrier in 2009 </li></ul><ul><li>Commercial contracts </li></ul>
  19. 35. Summary <ul><li>Fish Populations are constantly changing </li></ul><ul><li>What can be done to help improve? </li></ul><ul><ul><li>Habitat Protection and Restoration </li></ul></ul><ul><ul><li>Water Quality Issues </li></ul></ul><ul><ul><li>Aquatic Invasives </li></ul></ul><ul><ul><ul><li>Plants </li></ul></ul></ul><ul><ul><ul><li>Animals </li></ul></ul></ul><ul><ul><ul><li>Disease - VHS? </li></ul></ul></ul>
  20. 36. Goal is to Improve Fish Populations and Fishing
  21. 37. Thank You Questions ?