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