CONTENTS

 

Abstract

Introduction

Study Objectives

Purpose and Scope

Study Methods

Water Quality

Copper-Avoidance Tests

Computation of Avoidance Response

Statistical Analysis of Avoidance Response

Acute-Toxicity (Mortality) Tests

Avoidance Response and Mortality of Juvenile Brown Trout in Tests with Copper-Sulfate-Treated Water

Water Quality

Water Temperature

Dissolved Oxygen Concentration, pH, and Specific Conductance

Dissolved Copper Concentration

Copper-Avoidance Responses

Channel Preference

Gross Avoidance Response

Net Avoidance Response

Avoidance Threshold Concentration

Mortality Response

Implications of Copper Treatment for Brown Trout Populations in West Branch Reservoir

Toxicity-Mitigating Factors that Warrant Further Consideration

Age and Size of Fish

Avoidance Capability

Acclimation to Metals

Seasonal Water-Quality Changes

Horizontal and Vertical Distribution of Individual Fish

Alternative Exposure-Test Design

Conclusions

References Cited

 

FIGURES

 

1. Map showing the location of the test facilities at West Branch Reservoir, Putnam County, N.Y.

2. Diagram showing plan view of trout-exposure fluvarium used in copper-avoidance tests at West Branch Reservoir, June 26 through July 3, 1997

3. Box and whisker plots showing measured dissolved copper concentrations from treatment and control channels during the six copper-avoidance tests in water from West Branch Reservoir, June 26 through July 3, 1997

4. Graph showing cumulative frequency of brown trout distributions in treatment and control channels and in the decision area during avoidance tests in control exposures and at six copper concentrations in water from West Branch Reservoir, June 26 through July 3, 1997

5. Box and whisker plots showing frequency distribution of median net avoidance or attraction responses of juvenile brown trout exposed to six dissolved copper concentrations and to control water from West Branch Reservoir, June 26 through July 3, 1997

6. Graph showing mean net avoidance or attraction response during exposure of brown trout to six dissolved copper concentrations and to control water from West Branch Reservoir, June 26 through July 3, 1997

7. Graph showing percent mortality of juvenile brown trout after 96 hours of exposure to six dissolved copper concentrations and to control water during acute-toxicity tests at West Branch Reservoir, June 26 through 30, 1997

 

TABLES

 

1. Statistical summary of selected water properties in control channel and treatment channel of fluvarium during copper-avoidance tests at six target concentrations at West Branch Reservoir, Putnam County, N.Y., June 26 through July 3, 1997

2. Mean concentrations and standard deviations for selected constituents of control water during copper-avoidance and acute-toxicity tests at West Branch Reservoir, June 26 through July 3, 1997

3. Target concentrations, mean measured concentrations, and standard deviations of dissolved copper in control channel and treatment channel of fluvarium during copper-avoidance tests at West Branch Reservoir, June 26 through July 3, 1997

4. Frequency distribution of brown trout location, right-channel preference, and treatment-channel preference in fluvarium during exposures to untreated (control) water before each copper exposure in avoidance tests at West Branch Reservoir, June 26 through July 3, 1997

5. Brown trout avoidance responses to exposure to water containing copper sulfate at six concentrations in fluvarium tests at West Branch Reservoir, June 26 through July 3, 1997