Sacramento Perch were historically abundant predators throughout the Central Valley of California, where they occupied sloughs, lakes, and slow moving rivers. Today they are rare in their native waters, but still exist in Clear Lake and Alameda Creek/Calaveras Reservoir, as well as in some farm ponds and reservoirs. They have been introduced through the state including the upper Klamath basin, upper Pit River watershed, Walker River watershed, Mono Lake watershed, and Owens River watershed, and may exist in Sonoma Reservoir in the Russian River watershed. Sacramento Perch are most often found in warm reservoirs and ponds where summer temperature range form 18-28°C. Sacramento Perch are capable of surviving high temperatures, high salinities (up to 17 ppt), high turbidity, and low water clarity. Though Sacramento Perch are often found in clear water among beds of aquatic vegetation, they achieve greater numbers in turbid lakes absent of plants. Typically they are found along the bottom of inshore regions. Young-of-year perch form shoals in these areas where aquatic and overhanging vegetation provide cover. Sacramento Perch are most abundant where other centrarchids are absent. They feed by stalking, and prey items vary with time, availability, and fish size. Sacramento Perch are opportunistic and feeding occurs all day with peaks at dawn and dusk. Their diet is more diverse in summer than in winter. Young-of-year fish feed primarily on small crustaceans found on plants and in the substrate. Juvenile perch in Clear Lake were found to feed mostly on copepods and later cladocerans. Aquatic insect larvae and pupae become increasingly important as the fish grow. Adult fish may begin to feed on other fish, including young-of-year perch. Growth is variable and factors such as diet, overcrowding, and gender affect growth rates. Females tend to be larger than males and adult fish grow more in weight than in length. Sacramento Perch reach sexual maturity in year 2 or 3 and generally spawn from March through early August when water temperatures range from 18-29°C. Prior to spawning, perch gather in shallow areas abundant with filamentous algae and macrophytes. These assembly areas may also have submerged roots, rock piles, and sticks. Male fish begin defending territories along shore where they create shallow nests. They vehemently defend their space until the arrival of a female perch, at which time they begin courting. The male and female perch release eggs and milt simultaneously, and upon completion the female perch abandons the nest. Females spawn with multiple males, producing a total of about 8,400-125,000 eggs. Egg production varies with body size. Male perch guard their nests and the embryos for several days. The emergent larvae are planktonic for a time period assumed to be about 1-2 weeks.
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