''Percopsis omiscomaycus'', also known as the trout-perch, the grounder or the sand minnow, is one of two species in the family Percopsidae. Its name comes from the Greek root words ''perc'', meaning

perch Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Per ...

and ''opsi'' meaning appearance. The species name ''omiscomaycus'' is thought to be derived from a Native American word meaning ''trout''. These are freshwater fish that prefer clear to slightly turbid water, and are found in rivers and lakes throughout North America.Bosanko, Dave (2007), "Fish of Minnesota – Field Guide", pp. 162–163, Adventure Publication, Cambridge, MN. They are a generally small fish found in deep waters by day, but which migrate to shallower waters at night.They are most often seen washed up on beaches and are rarely seen alive or correctly identified. The trout-perch possess characteristics similar to both the

trout Trout are species of freshwater fish belonging to the genera '' Oncorhynchus'', '' Salmo'' and '' Salvelinus'', all of the subfamily Salmoninae of the family Salmonidae. The word ''trout'' is also used as part of the name of some non-salm ...

and the

.Bramblett, Robert, "Montana Cooperative Fishery Research Unit", Department of Ecology, Montana State University-Bozeman.http://www.fisheriessociety.org/AFSmontana/SSCpages/Trout-perch.htm They are an important source of food for many predator fish such as

walleye The walleye (''Sander vitreus'', synonym ''Stizostedion vitreum''), also called the yellow pike or yellow pickerel, is a freshwater perciform fish native to most of Canada and to the Northern United States. It is a North American close relat ...

northern pike The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (the pikes). They are typical of brackish and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). They are known simply as a p ...

, and

lake trout The lake trout (''Salvelinus namaycush'') is a freshwater char living mainly in lakes in northern North America. Other names for it include mackinaw, namaycush, lake char (or charr), touladi, togue, and grey trout. In Lake Superior, it can also ...

. They are not a major human fishery, but are occasionally used as a bait fish.

Description

The trout-perch has been found at sizes of total length and the average total length is . There are no distinguishing characteristics between males and females. They are overall silvery or nearly transparent in appearance with rows of dark spots on along the sides of their bodies both along their lateral line and above it. Their fins are almost entirely transparent. These fish have thick bodies with a long head, long snout, and a small mouth. They have a single dorsal fin containing 1–3 spines and 10–11 soft rays. They also have an

adipose fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

, similar to

, which helps to distinguishes them from their look-alike species, the

yellow perch The yellow perch (''Perca flavescens''), commonly referred to as perch, striped perch, American perch, American river perch or preacher is a freshwater perciform fish native to much of North America. The yellow perch was described in 1814 by Sam ...

and the

. Their tail or

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

is forked. Like most bony fish, the trout-perch has thin, flexible plates of bone or

leptoid scale A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as ...

s. Their particular leptoid scales are

ctenoid scale A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as w ...

s that are similar to the

's.

Distribution and habitat

The trout-perch is found throughout North America, from

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

and

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S. ...

to the

Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augu ...

basin in

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

. They are found in the

Great Lakes The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lak ...

region, as well as the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it fl ...

Basin which extends its range to include:

Iowa Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to th ...

Missouri Missouri is a state in the Midwestern region of the United States. Ranking 21st in land area, it is bordered by eight states (tied for the most with Tennessee): Iowa to the north, Illinois, Kentucky and Tennessee to the east, Arkansas t ...

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the O ...

Mississippi Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...

, and

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...

. They have also been spotted in

North Dakota North Dakota () is a U.S. state in the Upper Midwest, named after the indigenous Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minnesota to the east, So ...

Montana Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columb ...

and

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the B ...

. Trout-perch prefer clear to slightly

turbid Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Fluids can ...

water with sandy and gravelly bottoms. They avoid shallow soft-bottomed areas. They participate in a daily vertical migration, traveling from deep water during the day to shallow waters at night. This behavior is not only very important to their predators; the

, the

, and the

, but also in transporting nutrients in thermally stratified lakes. The nocturnal migration allows for foraging under the cover of night. The trout-perch feeds on a variety of small invertebrates including insect larvae and

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s. Juveniles feed on

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. Larger adults will eat small fish such as the

johnny darter The johnny darter (''Etheostoma nigrum'') is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to shallow wat ...

Breeding

The trout-perch becomes sexually mature at 1–3 years of age. The

spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...

season is May through August. Spawning sites consist of sandbars and rocks in lakes or on gravel or sand in tributary streams. Three to four males will surround a single female and release their sperm as the female is releasing her eggs. The eggs will be

fertilized Fertilisation or fertilization (see spelling differences), also known as generative fertilisation, syngamy and impregnation, is the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. Proce ...

and sink to the bottom of the lake. A single female can lay 200–700 eggs, which receive no parental care. The eggs will hatch in six days when the water temperature is . The life span of the trout-perch is around 4 years.

Ecological role

Although the trout-perch are abundant fish, their ecological role have not been well studied and are still not well understood, yet it is believed the trout-perch plays an important role at maintaining the equilibrium of its habitat. A study was conducted in Saginaw Bay, Lake Huron to learn about the ecological role of the trout-perch. Some results were collected, but there is still more to learn about this species. An important finding referred to the energy content of the trout-perch, which was higher than other similar species. The energy content of the trout-perch was 4795 joules, whereas

and round goby energy content were lower; 4662 joules and 3740 joules respectively. These findings are the main reason, scientists believe the trout-perch is an important source of food for other species in their habitat. Another finding showed that trout-perch prefer to feed from

Chironomidae The Chironomidae (informally known as chironomids, nonbiting midges, or lake flies) comprise a family of nematoceran flies with a global distribution. They are closely related to the Ceratopogonidae, Simuliidae, and Thaumaleidae. Many specie ...

larvae (lake flies larvae), but during some months and trout-perch sizes, there was a slight difference in the feeding source. Bigger fish of this species preferred to feed on Amphipoda, whereas smaller fish feed on

Zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

. Lake flies, lake flies larvae, and Amphipoda, seem to be the most important diet items for trout-perch in Saginaw Bay. The diet seemed to be the same for trout- perch in other systems besides Saginaw Bay, Lake Huron. Therefore, Trout-perch showed to be numerically important for the area since it seem to help to maintain the proper amount of species in its environment by serving as a food source and by preying on species, which are increasing and their increased can affect the ecosystem equilibrium.

Parasites

Trout-perch fish have been found infected by a variant of ''Myxobolus'', known as ''Myxobolus intramusculi'', a protist that acts as a muscular parasite. A study found that this strain of protist produces smaller (13-14.5 micrometres long vs 15-17 micrometres long), yet identically-shaped (narrow pyriform) spores than the original strain of protozoa and affects primarily within red and white muscle fibers and only rarely among the subdermal connective tissue in the trout-perch. The parasite grows until it replaces the entire content of the trout-perch cell and appears its developments stops abruptly before rupturing the outer cell membrane of the host cell which means it does not damage the cell significantly and does not have a lethal effect on the host. All the infected trout-perch seemed to have normal health and not any muscle deterioration. The only obvious effect of the parasite was a localized cyst on the area with infected cells. The parasites do not have lethal effects on trout-perch and these parasites cannot be transmitted from fish to humans.

References

{{Taxonbar, from=Q2521669 Percopsiformes Fish of North America Fish of the Great Lakes Fish described in 1792 Freshwater fish of North America