Yellow Perch

The yellow perch has an elongate, laterally compressed body with a subterminal mouth and a relatively long but blunt snout which is surpassed in length by the lower jaw. They have about 800 fine, brush-like teeth arranged in bands along their jaws and on the roof of their mouth. Their bodies are rough to the touch because of their ctenoid scales. Like most perches, the yellow perch has two separate dorsal fins. The anterior (or first) dorsal fin contains 12–14 hard spines, while the posterior (or second) dorsal fin has two or three hard spines at the front followed by 12–13 soft rays. The anal fin has two spines and 7–8 soft rays. The opercula tips are spined, and the anal fin has two spines. The pelvic fins are close together, and the homocercal caudal fin is forked. Seven or eight branchiostegal rays are seen.

Yellow perch are native to the tributaries of the Atlantic Oceans and Hudson Bay, particularly the Great Lakes–St. Lawrence River and Upper Mississippi River basins, the latter connecting to the former via canals such as the Illinois and Michigan Canal and the Chicago Sanitary and Ship Canal. In Canada, its native range includes all the Great Lakes basin, and from Nova Scotia to the Prairie provinces north to the Mackenzie River, and it is also common in the Great Slave Lake. In the United States, its native range extends south into Ohio and Illinois, and throughout most of the northeastern United States. Native distribution was driven by postglacial melt from the Mississippi River. It is also considered native to the Atlantic Slope basin, extending south to the Savannah River.

Primarily, age and body size determine the diets of yellow perch. Zooplankton is the primary food source for larval and fry perch. By age one, they become fingerlings and shift to macroinvertebrates such as midges and mosquito larvae. Older perch feed on aquatic invertebrates, fish eggs, crayfish, mysid shrimp and other juvenile fish. About 20% of the diet of a yellow perch over 32 g (1.1 oz) in weight consists of small fish. Adult perch have been known to be predominantly piscivorous and even cannibalistic in some cases. Maximum feeding occurs just before dark, with typical daily consumption averaging 1.4% of their body weight.

Yellow perch spawn once a year in spring using large schools and shallow areas of a lake or low-current tributary streams. They do not build a redd or nest. Females have the potential to spawn up to eight times in their lifetimes. Two to five males go to the spawning grounds first and are with the female throughout the spawning process. The female deposits her egg mass, and then at least two males release their milt over the eggs, with the total process taking about five seconds. The males stay with the eggs for a short time, but the females leave immediately. No parental care is provided for the eggs or fry. The average clutch size is 23,000 eggs, but can range from 2,000 to 90,000. The egg mass is jelly-like, semibuoyant, and can reach up to 2 m long. The egg mass attaches to some vegetation, while the rest flows with the water current.