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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 SciencesUniversity of Washington
Chemical Regulation Changes Permitting requirements
Chemicals Used Renovate 3 (triclopyr) Reward (diquat) Sonar AS (fluridone)
INTRODUCTION
Behavioral Responses and Herbicide Exposure Improve ecological relevance of
toxicity test results Avoidance and attraction
INTRODUCTION
Avoidance Test Methods Y-mazes Counter-Current Chambers Laminar Flow Systems
INTRODUCTION
INTRODUCTION
Chemical Clean
Counter-Current Chamber
Chemical Clean
Y-maze
Chemical Clean
Laminar Flow
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
METHODS
METHODS
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
METHODS
METHODS
Scoring method Position as a ratio of tube length, 0
to 1
Inlet Outlet
Mean Fish Position0.50
0.25 0.50 0.75
Minute 14
METHODS
0 1
Inlet Outlet
Mean Fish Position0.66
Chemical 0.45 0.60 0.85
Minute 16
Photograph taken each minute (total 45) to calculate mean position
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
METHODS
METHODS
0.4
0.5
0.6
0 5 10 15 20 25 30 35 40 45
Test Minute
Mea
n P
osit
ion
Avoidance
Clean Flow Period 1
Attraction
Clean Flow Period 3Chemical Flow Period 2
Period 2 Mean Position
Period 1 Mean Position
Theoretical Response - Fast - Assessment by Level
METHODSTheoretical Response - Slow - Assessment by Level
0.4
0.5
0.6
0 5 10 15 20 25 30 35 40 45
Test Minute
Mea
n P
osit
ion
Avoidance
Clean Flow Period 1
Attraction
Clean Flow Period 3Chemical Flow Period 2
Period 2 Mean Position
Period 1 Mean Position
METHODSTheoretical Response - Slow - Assessment by Slope
0.4
0.5
0.6
0 5 10 15 20 25 30 35 40 45
Test Minute
Mea
n P
osit
ion
Avoidance
Clean Flow Period 1
Attraction
Clean Flow Period 3Chemical Flow Period 2
Period 2 Mean Slope
Period 1 Mean Slope
RESULTS
Calcium Hypochlorite 1.6 ppm
0.300
0.400
0.500
0.600
0.700
0.800
0 5 10 15 20 25 30 35 40 45
Test Minute
Mea
n P
osit
ion
Avoidance
Clean Flow Period 1
Attraction
Clean Flow Period 3Chemical Flow Period 2
RESULTS
0.300
0.400
0.500
0.600
0.700
0.800
0 5 10 15 20 25 30 35 40 45
Test Minute
Mea
n P
osit
ion
Avoidance
Clean Flow Period 1
Attraction
Clean Flow Period 3Chemical Flow Period 2
Sonar AS 900 ppm
RESULTS
Analysis
Significant?
P-value
Result
1.6 ppm
Slope yes 0.09 Avoidance
1.6 ppm
Position
no 0.12 No Effect
Calcium Hypochlorite
RESULTS
Analysis
Significant?
P-value
Result
2.5 ppm
Slope no 0.50 No Effect
2.5 ppm
Position
no 0.49 No Effect
25 ppm
Slope no 0.77 No Effect
25 ppm
Position
yes 0.07 Attraction
Renovate 3
RESULTS
Analysis
Significant?
P-value
Result
1.37 ppm
Slope no 0.25 No Effect
1.37 ppm
Position
no 0.40 No Effect
13.7 ppm
Slope yes 0.08 Attraction
13.7 ppm
Position
no 0.56 No Effect
Reward
RESULTS
Analysis
Significant?
P-value
Result
90 ppb Slope no 0.40 No Effect
90 ppb Position
no 0.96No Effect
900 ppb
Slope no 0.47 No Effect
900 ppb
Position
no 0.35 No Effect
Sonar AS
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
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
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
