Management of undesirable fish species

• Lecture Outline

– Species

– Management options

– Case studies

What is an undesirable fish species
Box 15.1 from book

1) A species that is detrimental to the biological balance of an aquatic system

2) Adversely affects native fishes

3) Species that hosts pathogenic organisms

4) Does not contribute to commercial, sport, or provide forage base

5) Inhibits development of sport or commercial fishery

6) Interferes with other management practices

Undesirable fish: examples

1) Gizzard shad

a) 54% of current control efforts

b) High reproductive potential

c) Competition - zooplankton

d) Ecosystem effects

i) Increase nutrient loads

ii) Release nutrients from sediments

2) Common carp

a) Competition – benthic invertebrates

b) High reproductive potential

c) Habitat modification

i) Turbidity

ii) Release of nutrients from sediments

d) High reproductive potential

3) Stunted sunfishes

a) Competition – zooplankton and benthic invertebrates

b) High reproductive potential

4) Bullheads (Ameiurus spp.)

a) Competition

b) High reproductive potential

c) Habitat modification

i) Turbidity

5) Suckers

a) Competition

b) Habitat modification

c) Large-bodied

d) Well suited to reservoir environment

Steps in planning a fish control operation

1) Justification for project

a) Angler attitudes

b) Resource use data

c) Correlative data

2) Determine what method to use

a) Chemical

b) Biological

c) Mechanical

3) Environmental assessment

a) NEPA compliance

b) State regulatory agencies

Chemical Removal

1) Rotenone

2) Lampricide

a) TFM

b) Squoxin

i) Control northern pikeminnow

3) Partial treatments of spawning sites

Biological Control

1) Hybrid fishes

2) Sterile fishes

a) Sterile fishes will compete with other fish

b) Reduce the number of fertilized eggs

Mechanical Control

1) Barriers

2) Commercial fishing

3) Water level manipulation

4) Trap nets

a) Carp and bullheads are rheotaxic

5) Other removal methods

a) Electrofishing

b) Gill nets

Combined treatments

1) Use chemicals to reduced numbers followed by the introduction of predatory sport fishes

Control of undesirable fish: Case Studies

1) Sea lamprey in Great Lakes

2) Native trout

a) Construction of barriers

b) Chemical treatment of stream above barrier

3) Strawberry Reservoir, Utah