Avoidance of Aquatic Herbicides by Juvenile Salmonids

1. Avoidance of Aquatic Herbicides by Juvenile Salmonids CA Curran, JM Grassley, LL Conquest, and CE Grue Washington Cooperative Fish and Wildlife Research Unit School of Aquatic and Fishery Sciences University of Washington

2. INTRODUCTION • Chemical Regulation Changes • Permitting requirements • Chemicals Used • Renovate 3 (triclopyr) • Reward (diquat) • Sonar AS (fluridone)

3. INTRODUCTION • Behavioral Responses and Herbicide Exposure • Improve ecological relevance of toxicity test results • Avoidance and attraction

4. INTRODUCTION • Avoidance Test Methods • Y-mazes • Counter-Current Chambers • Laminar Flow Systems

5. Chemical Clean Chemical Clean Counter-Current Chamber Chemical Clean Y-maze Laminar Flow INTRODUCTION

6. OBJECTIVE • Do juvenile chinook avoid the herbicides at maximum concentrations and 10 times those concentrations? • Renovate 3 (triclopyr): 2.50 and 25.0 ppm • Reward (diquat): 1.37 and 13.7 ppm • Sonar AS (fluridone): 90 and 900 ppb

7. METHODS

8. METHODS

9. METHODS

10. METHODS • 45 minute test • 0-14 minutes clean water flow • 15-30 minutes chemical flow • 31-45 minutes clean water flow • Overall design focused on initial response to chemical flow • Digital photos were taken every minute

11. METHODS

12. METHODS • Scoring method • Position as a ratio of tube length, 0 to 1 Minute 14 0 1 0.75 0.50 0.25 Inlet Outlet Mean Fish Position0.50

13. METHODS • Photograph taken each minute (total 45) to calculate mean position Minute 16 0.85 0.60 Chemical 0.45 Inlet Outlet Mean Fish Position0.66

14. METHODS • Data Analysis • Paired t-test to compare difference in mean position by minute blocks 0-14, 15-30, 31-45 • Paired t-test to compare difference in slopes of mean positions within minute blocks • Alpha level = 0.10

15. METHODS Theoretical Response - Fast - Assessment by Level

16. METHODS Theoretical Response - Slow - Assessment by Level

17. METHODS Theoretical Response - Slow - Assessment by Slope

18. RESULTS Calcium Hypochlorite 1.6 ppm

19. RESULTS Sonar AS 900 ppm

20. RESULTS Calcium Hypochlorite

21. RESULTS Renovate 3

22. RESULTS Reward

23. RESULTS Sonar AS

24. CONCLUSIONS • Original methods needed alterations • Replication, tube shape, chemical delivery • The apparatus functioned as expected • Positive control results • New statistical approach - change in mean position vs categorical tests • Attraction to 10 times the maximum concentration of Renovate and Reward

25. FUTURE WORK • Examination of olfactory performance following static exposure • Examination of concentrations at time of application and rates of diffusion • Effects of different testing procedures on avoidance/attraction results

26. ACKNOWLEDGEMENTS • Funding was provided by Washington State Department of Ecology, SePro Corporation, and the School of Aquatic and Fishery Sciences and the Washington Cooperative Fish and Wildlife Research Unit at the University of Washington. • A scholarship from Weed Science Society of America made my participation in this research possible • Facilities provided by USGS’s Marrowstone Marine Station