Fish Kills

• Lecture Outline

– Procedures for investigating a fish kill

– Counting dead fish

– Economic value of fish kills

• Assignments

1) Fish kill – greater that usual and sudden death of fish or other aquatic organisms

2) What causes fish kills?

a) Agriculture

b) Aquaculture

c) Industry

d) Mining

e) Municipal

f) Reservoir management

g) Natural causes (weather)

Who is responsible for fish kill investigations

1) State agencies

a) Fish and Game

b) Department of Health and Environment

2) Federal agencies

a) National Marine Fisheries Service

b) U.S. Fish and Wildlife Service

c) Environmental Protection Agency

3) Communication with other agencies is a priority

Field investigation

1) Purpose to document information on size and cause of incident

2) Determine source of pollution

3) Water sampling

a) Affected area as well as controls

4) Water testing

a) Temperature, dissolved oxygen, pH, conductivity, turbidity, chlorine, ammonia, heavy metals, pesticides and herbicides

5) Sediment samples

a) Can retain contaminants

6) Fish and invertebrate counts

7) Record keeping

a) Photographs

Counting dead fish

1) Counts will underestimate numbers killed

2) Many instances it will be time consuming to count all fish

Economic value of fish

1) Replacement costs 

a) Fish – Hatchery production costs

b) Restocking and restoration – improving habitat and transport of fishes

c) Investigation and administration – costs of the fish kill investigation

d) User value – cost per day incurred by anglers