Management of Undesirable Fish Species Chapter 15

Undesirable Species Any species that does not meet human needs

Undesirable Species Not contribute to sport fishery, forage base Inhibit development, maintenance of desirable fish Detrimental to biological balance

Undesirable Species Reservoir for pathogenic organisms (aquaculture) Interfere with other wildlife management practices

Most Control Efforts Herrings (gizzard shad) Minnows (common carp) Sunfish Suckers Bullhead catfishes

Control Methods Chemical Biological Mechanical

Chemical Control Usually used for complete removal Also effective for partial removals Spawning sites Lake sections “Thinning” of stunted game fish stocks

Ideal Chemical Species-specific Easy/safe to apply Quickly degrades to harmless form without need for detoxicants Harmless to nontarget organisms

Ideal Chemical Effective across range of water quality Registered for aquatic use NO SUCH CHEMICAL!

Current Registered Piscicides Rotenone and antimycin General fish toxicants

Current Registered Piscicides TFM and Bayluscide Lampricides

Lampricides Sea lamprey Larva or ammocoete

Lampricides Granular Bayluscide

Chemical Control Effective time period - 1 to 15 years most common Effective time period - 1 to 15 years most common Some up to 30 years Some up to 30 years

Biological Control Predators to control forage, stunted fish Predators to control forage, stunted fish

Biological Control Problems: Problems: Gizzard shad Gizzard shad Yellow perch Yellow perch “Sunfish” “Sunfish” Common carp Common carp Other minnows Other minnows Solutions: Largemouth bass Walleye Northern pike Striped bass Striped bass hybrids Muskellunge

Biological Control Controlling reproduction Forage fish introductions Unwanted competitive interactions Underexploited fishes Encourage new sport, commercial fisheries

Mechanical Control Water level manipulations Only on reservoirs

Mechanical Control Traps Traps Barriers Barriers Commercial fishing Commercial fishing Electricity Electricity Labor-intensive - CPUE declines with decreasing populations Labor-intensive - CPUE declines with decreasing populations Problems: Common carp Other minnows Suckers “Sunfish” Yellow perch