Percopsis omiscomaycus also known as the trout-perch, the grounder or the sand minnow, is one of two species in the family Percopsidae. They are freshwater fish that prefers clear to slightly turbid water. They are most often seen washed up on beaches and are rarely seen alive or correctly identified. They are found in rivers and lakes throughout North America. Its name comes from the Greek root words perc, meaning perch and opsi meaning appearance. The species name omiscomaycus is thought to be derived from a Native American word meaning trout. The trout-perch possess characteristics similar to both the trout and the perch. They are an important source of food for many predator fish such as walleye, northern pike, and lake trout. They are a generally small fish found in deep waters by day, but which migrate to shallower waters at night. They are not a major human fishery, but are occasionally used as a bait fish.
The trout-perch is found throughout North America, from Canada and Alaska to the Potomac river basin in Virginia. They are found in the Great lakes making them present in Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania and Wisconsin. They are also found in the Mississippi River Basin which extends its range to include: Iowa, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana. They have also been spotted in North Dakota, Montana and West Virginia.
The trout-perch has been found at sizes of 20.0 centimetres (7.9 in) total length (TL) but the average total length is 8.8 centimetres (3.5 in). 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.
Scales and fins
They have a single dorsal fin containing 1–3 spines and 10–11 soft rays. They also an adipose fin, similar to trout, which helps to distinguishes them from their look a likes the yellow perch and the walleye. Their tail or caudal fin is forked. As most bony fishes, the trout-perch has thin, flexible plates of bone or leptoid scales. Their particular leptoid scales are ctenoid scales that are similar to the perch's.
Habitat, diet, and predators
Trout-perch prefer clear to slightly turbid water with sandy and gravely bottoms. They avoid shallow soft-bottomed areas. They participate in a daily migration, traveling from deep water during the day to shallow waters at night. This behavior is not only very important to their predators; the walleye, the northern pike, and the lake trout, 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 crustaceans. Juveniles feed on zooplankton. Larger adults will eat small fish such as the johnny darter.
The trout-perch becomes sexually mature at 1–3 years of age. The spawning season is May through August. The spawning site consists 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 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 20–23 °C (68–73 °F). The life span of the trout-perch is around 4 years.
- NatureServe (2013). "Percopsis omiscomaycus". IUCN Red List of Threatened Species. Version 3.1. International Union for Conservation of Nature. Retrieved January 26, 2014.
- Bosanko, Dave (2007), "Fish of Minnesota – Field Guide", pp. 162–163, Adventure Publication, Cambridge, MN. ISBN 1-591-93192-4
- Bramblett, Robert, "Montana Cooperative Fishery Research Unit", Department of Ecology, Montana State University-Bozeman.http://www.fisheriessociety.org/AFSmontana/SSCpages/Trout-perch.htm