''Percopsis omiscomaycus'', also known as the trout-perch, the grounder or the sand minnow, is one of two species in the family

Percopsidae Percopsidae is a family of fish in the order Percopsiformes, with one extant genus with two species, both endemic to North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemi ...

. Its name comes from the Greek root words ''perc'', meaning

perch Perch is a common name for freshwater fish from the genus ''Perca'', which belongs to the family Percidae of the large order Perciformes. The name comes from , meaning the type species of this genus, the European perch (''P. fluviatilis'') ...

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 North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

.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 (: trout) is a generic common name for numerous species of carnivorous freshwater ray-finned fishes belonging to the genera '' Oncorhynchus'', ''Salmo'' and ''Salvelinus'', all of which are members of the subfamily Salmoninae in the ...

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 (taxonomy), synonym ''Stizostedion vitreum''), also called the walleyed pike, yellow pike, yellow pikeperch or yellow pickerel, is a freshwater perciform fish native to most of Canada and to the Northern ...

northern pike The northern pike (''Esox lucius'') is a species of carnivorous fish of the genus ''Esox'' (pikes). They are commonly found in brackish water, moderately salty and fresh waters of the Northern Hemisphere (''i.e.'' holarctic in distribution). T ...

, and

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

. 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 The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelia ...

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 moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only b ...

, 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 or preacher is a freshwater perciform fish native to much of North America. The yellow perch was described in 1814 by Samuel Latham Mitchill fr ...

and the

. Their tail or

caudal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported only ...

is forked. Like most bony fish, the trout-perch has thin, flexible plates of bone or leptoid scales. Their particular leptoid scales are ctenoid scales that are similar to the

's.

Distribution and habitat

The trout-perch is found throughout

, from

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

and

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

to the

Potomac River The Potomac River () is in the Mid-Atlantic (United States), Mid-Atlantic region of the United States and flows from the Potomac Highlands in West Virginia to Chesapeake Bay in Maryland. It is long,U.S. Geological Survey. National Hydrography D ...

basin in

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

. 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 spanning the Canada–United States border. The five lakes are Lake Superior, Superior, Lake Michigan, Michigan, Lake Huron, H ...

region, as well as the

Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...

Basin which extends its range to include:

Iowa Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it border ...

Kentucky Kentucky (, ), officially the Commonwealth of Kentucky, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Illinois, Indiana, and Ohio to the north, West Virginia to the ...

Tennessee Tennessee (, ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders Kentucky to the north, Virginia to the northeast, North Carolina t ...

Arkansas Arkansas ( ) is a landlocked state in the West South Central region of the Southern United States. It borders Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, Texas to the southwest, and Oklahoma ...

Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ...

, and

Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...

. They have also been spotted in

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

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

and

West Virginia West Virginia is a mountainous U.S. state, state in the Southern United States, Southern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States.The United States Census Bureau, Census Bureau and the Association of American ...

. 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 both water clarity and wate ...

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 Nocturnality is a ethology, behavior in some non-human animals characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnality, diurnal meaning the opposite. Nocturnal creatur ...

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 (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s. Juveniles feed on

zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

. 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 ...

Breeding

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

spawning Spawn is the Egg cell, eggs and Spermatozoa, sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is ...

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 zygote and initiate its development into a new individual organism or off ...

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 Lake Huron ( ) is one of the five Great Lakes of North America. It is shared on the north and east by the Canadian province of Ontario and on the south and west by the U.S. state of Michigan. The name of the lake is derived from early French ex ...

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 Chironomidae , commonly known as non-biting midges or chironomids , are a family of Nematoceran flies with a global distribution. They are closely related to the families Ceratopogonidae, Simuliidae, and Thaumaleidae. Although many chironomid ...

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 Amphipoda () is an order (biology), order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods () range in size from and are mostly detritivores or scavengers. There are more than 10,700 amphip ...

, whereas smaller fish feed on

Zooplankton Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...

. 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 ''Myxobolus'' is a genus of myxozoa that includes important parasites of fish like '' Myxobolus cerebralis''. The genus is polyphyletic, with members scattered throughout the myxozoa. Some stages of ''Myxobolus'' species were previously thought ...

'', 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