Sacramento Perch

The body shape of this fish is laterally compressed, and it is considered to be deep-bodied for a Centrarchid species. Being deep-bodied refers to it being wide in length from its ventral to dorsal side. On average, its depth is 2.5 times greater than the average length of all other Centrarchids. This fish has a slightly angled mouth in the superior position, indicating that it feeds on insects near the middle of the water column. The mouth is large, with numerous small teeth found on its jaws, tongue, and roof of its mouth. The dorsal fin has a strictly spiny portion with about 12–14 spines that is continuous, with the soft-rayed portion that has 10–11 spines. It has fairly large cycloid scales numerously ranging from 38 to 48 along the lateral line in an adult. It has a combination of white, silver, and dark brown colored scales.

The Sacramento perch is most identifiable by its irregular dark brown vertical bars that almost resemble stripes, giving it great cryptic coloration in dark and vertically broken-up habitats provided by aquatic plants. The females, however, tend to have these bars less prominent and have more of an even coloration with the silver scales. There are about 25–30 gill rakers in its gills, and has black spots on the operculum. During the breeding season, there tends to be more sexual dimorphism. …

Historically, the Sacramento perch was found throughout the Central Valley of California at elevations below 100 m. The Sacramento perch was very popular for recreational fishing. It was so abundant that this species was commonly used as a food fish eaten regularly. It inhabited sloughs, slow-moving rivers of the Pajaro and Salinas rivers, and lakes with emergent vegetation such as Clear Lake. This species has been eliminated from 90% of its natural habitat due to habitat destruction, egg predation by invasive fish species, and interspecific competition with other centrarchids, mainly bluegill. Sacramento perch are quite rare in their native range and are found primarily in warm, turbid, and alkaline farm ponds, reservoirs, and recreational lakes that it has been introduced into. Sacramento perch populations exist in six California watersheds, including Clear Lake Reservoir, Cedar Creek, Walker River, upper Owens River, Mono Lake, and Abbotts Lagoon. In Colorado, there were two successful introductions in private land, one in Abrams Lake and the other in Gilberts Pond. The growth rate of the fish here was very rapid, but spawning is yet to be determined. Sacramento perch populations in Nevada were transplanted in 1877 from the Sacramento River into Washoe Lake. Eventually, they were moved again into Pyramid and Walker Lake in 1880. …

Aquatic insects are critical to the Sacramento perch's diet. This fish mostly feeds on chironomid midge larvae and pupae found on the bottom or in aquatic plants during winter months. Triochopteran larvae and recently hatched boatmen are also common insect food sources. During the summer months, this fish will mostly feed on plankton and other surface organisms. The Sacramento perch is an opportunistic species and will generally prey upon whatever is in abundance. They have even been shown to eat mosquito larvae. However, eating mosquito larvae is rare because these fishes are mainly midwater swimmers and do not usually feed on terrestrial or flying insects. The younger and smaller adult perches mostly feed on small benthic crustaceans. As they grow, they move on to chironomid larvae and other fish, including their own species on rare occasions. Sacramento perch of Pyramid Lake have been found feeding on Tui chubs and Tahoe suckers. Based on experimental designs in aquariums, they usually hunt alone and will slowly stalk their prey for a period of time. Once their prey becomes comfortable and loses focus, it is unprecedentedly snatched by the perch's sudden burst toward the prey. This behavior differs from the bluegill, its main competitive species, which usually hunts in schools and is much more aggressive towards its prey. …