White Perch  (Morone americana)

DESCRIPTION

The White Perch (Morone americana) is an invading species that has become permanently established in Lake Erie, the Ohio River, and a few inland lakes. Prolific competitors of native fish species, white perch are believed to have the potential to cause declines of Great Lakes walleye populations. 

White Perch or White Bass (Why it matters) While the white bass is native to the Great Lakes, the white perch is an invader that may reduce populations of native fish such as walleye and white bass. Additionally, white bass can interbreed with white perch, which could dilute the gene pools of both species. White Perch Morone americana White Bass Morone chrysops Photo Credit & Source:  Wisconsin sea grant, http://www.seagrant.wisc.edu/greatlakesfish/framefish.html; Ohio Department of Natural Resources, http://www.dnr.state.oh.us/odnr/wildlife/fishing/fishid/whitepe.html Length: Usually 5-7 inches (127-178mm) 9-15 inches (average sport catches) Weight: Average 8 ounces 6 lbs. 7 oz. (world record ) Coloring: variable, dark grayish-green, dark silvery green, or dark brown to almost black on back; pale olive or silvery green on sides; silvery white on belly body is primarily silver, with dark green or gray on the back and white below; sides have 5-7 horizontal dark stripes Common Names: white perch, narrow-mouthed bass, silver perch, sea perch silver bass, white lake-bass, striped bass Found in Lakes: Michigan, Huron, Ontario, Erie and Superior Michigan, Huron, Ontario, and Erie   1. The body is deepest just ahead of, or at the beginning of, the dorsal fin. 1. The body is deepest below the dorsal fin and the depth remains fairly uniform below the entire spiny dorsal fin. 2. There are no lines or stripes on the back or sides. 2. From 6 to 10 dark lines run horizontally down the back and sides. 3. When the spiny dorsal fin is pulled erect, the soft dorsal fin also becomes erect. 3. When the spiny dorsal fin is pulled erect, the soft dorsal fin remains relaxed. 4. The second and third bony anal spines are almost exactly the same length. 4. Each of 3 bony anal fin spines are of different lengths and are arranged in ascending order. 5. The anal fin usually has 8 or 9 soft rays behind the 3 bony spines. 5. The anal fin usually has 11 or 12 soft rays behind the 3 bony spines. Photo credit & source: Ohio Sea Grant Fact Sheet 005, Is it a white bass or a white perch? by Fred L. Snyder, http://www.sg.ohio-state.edu/PDFS/PUBLICATIONS/FS/FS-005.pdf

IMPACTS

Eating the eggs of walleye, white bass, and other fishes
White perch have been found to eat the eggs of walleye (Stizostedion vitreum), white bass (Morone chrysops), other white perch and possibly other species as well. Fish eggs apparently are an important component of the diet of white perch in the spring months. At times, depending on which fish is spawning, the eggs of either walleye or white bass comprise 100% of the white perch’s diet. 

Hybridizing with native white bass
White perch, actually a species of the bass genus (Moronidae), have hybridized with native white bass in western Lake Erie. These hybrids were first noted in western Lake Erie in the early 1980s, the same time when white perch were increasing in abundance in this area. Since these hybrids are capable of back-crossing with parent species as well as crossing among themselves, they could dilute the gene pool of both parent species. This is the first known natural occurring hybrid in this genus; all other Morone hybrids were artificially produced. This hybridization is probably also occurring in the other Great Lakes.

Sources: 1. Pam Fuller, Southeastern Biological Science Center, National Biological Service;
2. Fishes of Wisconsin by George C. Becker (University of Wisconsin Press, 1983);
3. Freshwater Fishes of Canada by W.B. Scott and E.J. Crossman (Fisheries Research Board of Canada, 1973); 4. Wisconsin sea grant, http://www.seagrant.wisc.edu/greatlakesfish/framefish.html) 

Competing with native fish for food
White perch has competed with native yellow perch Perca flavescens for zooplankton. One evidence is that growth rates of yellow perch had declined since since invasion of white perch in Lake Erie, especially in the western basin. It was also determined that the two species had considerable diet overlap. They also found in one sample, white perch consumed 27 percent more food than yellow perch (Parrish and Margraf 1990). 
Parrish and Margraf (1994) speculated that competition between white perch and forage fishes, such as emerald shiner Notropis atherinoides and spottail shiner N. hudsonius, may actually be more complex and may be responsible for the declines of the latter species. Decline of these species could also affect walleye Stizostedion vitreum, the top predator in Lake Erie (Parrish and Margraf 1994). 
Within three years after being introduced into a Nebraska reservoir, white perch had completely replaced the previously dominant black bullhead Ameiurus melas. Species composition changed from 74 percent black bullhead to 70 percent white perch in that timeframe (Hergenrader and Bliss 1971).

Sources: 1. Parrish, D.L. and F.J. Margraf,  1990. Gastric evacuation rates of white perch, Morone americana, determined from laboratory and field data,  University of Vermont; 2. Parrish, D.L. and F.J. Margraf,  1994. Spatial and temporal patterns of food use by white perch and yellow perch in lake erie,  Journal of Freshwater Ecology 9(1):29-35; 3. Hergenrader, G. L., and Q. P. Bliss. 1971. The white perch in Nebraska. Transactions of the American Fisheries Society 100(4):734-738; 4. USGS Nonindigenous Aquatic Species: White Perch. 

Sources: 1. Pam Fuller, Southeastern Biological Science Center, National Biological Service;
2. Fishes of Wisconsin by George C. Becker (University of Wisconsin Press, 1983);
3. Freshwater Fishes of Canada by W.B. Scott and E.J. Crossman (Fisheries Research Board of Canada, 1973); 4. Wisconsin sea grant, http://www.seagrant.wisc.edu/greatlakesfish/framefish.html) 
5. Sgnis web page, http://www.sgnis.org/ 

Thoroughly rinse wetsuits and SCUBA gear with hot water, and allow to dry before using in an uninfested lake. 

Never transport minnows from an infested area. 

Use appropriate antifouling paints on boat hulls and motors in infested waters.

Always inspect and clean your boat before transporting it to another lake or river

Thoroughly drain and flush all boat compartments including bildg, live wells, marine toilets, anchor rope compartments, engine cooling systems, and any other areas that get wet.

Allow boats and trailers to dry thoroughly in the sun for at least four days prior to placing in unifested water.

A boat hull that feels "gritty" may have young, microscopic zebra mussels attached. High pressure (250 psi) hot water wash should be employed, and allow to dry for 4 days in the sun.

Run hot water through your engine intake system.

Empty your bait bucket on land, never into the water. 

Never dip your bait or minnow into one lake if it has water in it from another.

Never dump live fish from one water body into other waters.

Do not transport exotics, dead or alive.

Avoid using exotics as bait.

Clean all mud and plant matter from your boat, trailer, propeller, live well and anchors before leaving the landing.

Drain your live wells and bilge water before you leave infected area.

Let your boat and trailer dry in the sun for at least four days before you use it again in another lake or river.

Wash your boat with very hot water - at least 105°F (60°C).

(Source & Credit: Exotics of Lake Ontario by Jennifer Pultz, Sea Grant of Cornell University-State University of New York, Fact Sheet December 1995; Copies of this publication are available from New York Sea Grant, Rich Hall, SUNY College at Oswege, Oswege, NY 13126, (315) 341-3042; http://www.seagrant.sunysb.edu/DEFAULT.htm) 

Exotic species can be accidentally spread by boaters who travel from infested to uninfested waters. Some species (e.g., Round Goby, Zebra Mussel, Ruffe, Eurasian Watermilfoil) can be picked-up and transported on boating equipment including boats, trailers, motors, tackle, downriggers, anchors, axles, rollers, and centerboards. As a boater, you help prevent this from happening. To avoid spreading exotic species, follow these easy steps before transporting your boat to another waterway.

BEFORE leaving the boat launch

INSPECT your boat, trailer and equipment and remove any plants and animals.
DRAIN, on land, all water from the motor, livewell, bilge, and transom well. Some exotics may not be visible to the naked eye.
EMPTY your bait bucket on land. Never release live bait into a waterway, or transfer aquatic animals between waterways. 

AFTER leaving the boat launch

WASH your boat, tackle, trailer, and  other equipment to kill any exotic species not visible at the boat launch. This can be done with 104°F tap water, or a high-pressure sprayer. or
DRY  your equipment for at least five days-some exotics can survive for long periods of time out of water.
LEARN what these organisms look like, and know which waterways are infested. 
REPORT any new infestations to any Sea Grant or your Department of Natural Resources.

Source from Illinois-Indiana Sea Grant publication, IL-IN-SG-98-1, http://www.iisgcp.org/)

White Perch of the Great Lakes: Wisconsin Sea Grant     
     http://www.seagrant.wisc.edu/Communications/Publications/Fish/fwhiteperch1.html
This site includes general description, origin, and distribution information in the Great Lakes. 
How to distinguish white bass from white perch    
      http://www.seagrant.wisc.edu/Communications/Publications/Fish/bassorperch.html

White Perch, Nonindigenous Aquatic Species: U.S. Geological Survey (USGS)     
     http://nas.er.usgs.gov/fishes/accounts/moronida/mo_ameri.html
This site includes comprehensive information on identification, distribution, map, impacts, and useful references.  Sea Grant Nonindigenous Species Site - WHITE PERCH

White Perch: Sea Grant Nonindigenous Species Site (sgnis)     
     http://www.sgnis.org/
This site provides very excellent articles (including both abstract and full text) related to white perch.  

White Perch: Ohio Department of Natural Resources (ODNR)     
     http://www.dnr.state.oh.us/odnr/wildlife/fishing/fishid/whitepe.html
This page includes brief information about habitat, fish facts, habitat, size (Ohio record size), and so on.