1. A Multi-Agency Effort to Address Declines in Yellow Perch Abundance in Lake Michigan David Clapp Michigan Department of Natural Resources and Yellow Perch Task Group, Lake Michigan Technical Committee

2. Lake Michigan Recreational Yellow Perch Catch (Michigan Waters)

3. Is there a problem?

5. Age Distribution of Yellow Perch Catch Age 6 Age 3

6. Yellow Perch Sampling Fishery Independent versus Dependent Data

7. What steps have we taken to address perch declines? Step #1 - Formation of Yellow Perch Task Group (1994) Increased sampling coverage Gear standardization

8. Yellow Perch Task Group Sampling Locations

9. Summer Trawl and Seine Surveys Catch per unit effort Total length Age Abundance of other species

10. Gill Net Surveys Catch per unit effort Total length and weight Sex, Fecundity Scales, Otoliths

11. Lake Michigan Creel Survey Programs (Photo courtesy of The Hunting and Fishing Library)

12. What steps have we taken to address perch declines? Step #2 - Lakewide public meeting (Yellow Perch Conference - December, 1994 - Kenosha, Wisconsin) Protect spawning stock Conduct research on declining recruitment Enforce harvest regulations

13. Regulation changes

14. Step #3 - Conduct research on declining recruitment Hypotheses Egg stage:  Egg quality and/or egg mortality limits perch Diet:  Inappropriate diet limits larval survival Alewife / predation:  Alewife predation limits recruitment What steps have we taken to address perch declines?

15. Early Life History (Egg Stage)

16. Were maternal effects important? 986103 5147 Survival (number of individuals) Female Survival: 601 (1) - 1283 (8) Provided by: Christopher J. Heyer Chesapeake Biological Laboratory

17. A trade-off exists between yolk volume and larval size Large, old female perch = small yolk volume = large larvae Abundant food, many predators Small, young female perch = large yolk volume = small larvae Scarce food, few predators Provided by: Christopher J. Heyer Chesapeake Biological Laboratory Were maternal effects important?

18. Food Resources (Diet)

19. Mean ZP Density in June (No./L) 1020304050 Log (YOY YP CPUE) -2 0 2 4 6 96 97 98 88 89 90 Yellow Perch Survival versus Zooplankton Density Data provided by John Dettmers, Illinois Natural History Survey)

20. Alewife (Predation, Competition)

21. Yellow Perch Year Class Strength versus Alewife Abundance (Data provided by Steve Shroyer, Ball State University)

22. Other Predators (Photo courtesy of The Hunting and Fishing Library)

23. Other Predators

24. YEP(#) = Function (“Cycles” * (x+y+z+…)) What steps have we taken to address perch declines? Step #4 - Implementing Yellow Perch Research in Great Lakes Management

25. Yellow Perch Abundance Saginaw Bay - Lake Huron

26. YEP(#) = Function (“Cycles” * (a+b+c+d+…)) d b a c

27. Recreational Harvest Commercial Harvest

28. Implementing Perch Research Egg stage, diet, predators

29. Recreational and Commercial harvest Implementing Perch Research