White perch (Morone americana)

White perch.

Description

Appearance

The white perch is not a true perch but rather a fish in the temperate bass family. Adults range between seven to 12 inches in length. They have grayish-green to dark green-brown backs, silver sides and silver-white undersides. They generally do not have stripes.

Body Shape and Fins

The body is deep and laterally compressed, being deepest just ahead of the dorsal fin. The two dorsal fins are slightly joined by membrane at the base. The anal fin has three spines, with the second and third spine being the same length.

Biology

The white perch is a predacious and opportunistic feeder. Young feed primarily on zooplankton and adults feed on aquatic insect larvae, minnows and fish eggs. Spawning occurs over a period of 10 to 21 days with individual females expelling 20,000 and 150,000 eggs to be fertilized externally. The eggs stick to the bottom and hatch one to six days following fertilization.

Origin and Spread

The white perch is native to the Atlantic coastal region of the United States. It invaded the Great Lakes through the Erie and Welland canals, which bypass natural barriers. The species was unintentionally introduced into Lake Superior through the discharge of contaminated cargo ship ballast water as well as the improper use and disposal of live bait. Unauthorized stocking has been source of spread to inland waters in other states.

The first observation in Lake Superior’s Duluth Harbor was in 1986. The St. Louis River downstream of the Fond du Lac dam, Lake Superior, and its connected tributaries are listed as infested, but no other Minnesota water bodies are known to contain the species. Refer to the infested waters list for current distribution.

Don't be fooled by these look-alikes

 

Regulatory Classification

White perch (Morone americana) is a prohibited invasive species, which means it is unlawful (a misdemeanor) to possess, import, purchase, transport, or introduce this species except under a permit for disposal, control, research, or education.

 

Threat to Minnesota Waters

White perch infestations cause recreational, economic and ecological damage—changing how residents and visitors use and enjoy Minnesota waters.

  • Compete with native fish species and prey on native fish eggs.
  • Compete for zooplankton which may lead to algal blooms.
  • May hybridize with white bass.

 

What you should do

People spread white perch primarily through the improper use and disposal of live bait.

Whether or not a lake is listed as infested, Minnesota law requires water recreationists to:

  • Clean watercraft of all aquatic plants and prohibited invasive species.
  • Drain all water by removing drain plugs and keeping them out during transport.
  • Dispose of unwanted bait in the trash.
  • Dry docks, lifts, swim rafts and other equipment for at least 21 days before placing equipment into another water body.

Report new occurrences of white perch to the DNR immediately by contacting your DNR Invasive Species Specialist or log in and submit a report through EDDMapS Midwest.

 

Control Methods

There is no known effective population control for white perch in natural water bodies at this time.

 

Resources