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Trout-perch
Percopsis omiscomaycus
NatureServe conservation status
Global (G-rank): G5
State (S-rank): SNA
- Reason: In Utah this species was introduced and apparently has become established in Willard Bay Reservoir (Box Elder County) and in Utah Lake (Utah County).
External links
General information
The trout-perch, Percopsis omiscomaycus, is an interesting little fish that has been introduced to Willard Bay Reservoir, but is not native to Utah. The trout-perch is different from most other fish species because it has spiny fin rays, like a perch, but it also has an adipose fin (a small fleshy fin behind the dorsal fin), like a trout. The trout-perch is native to the Columbia River system.
Trout-perch spawn throughout the summer and primarily eat invertebrates and small fishes. The status of the trout-perch population in Willard Bay Reservoir is currently unknown. If the population is doing well, the trout-perch is likely an important forage fish for the many species of sport fish in the reservoir.
Species range
Sigler and Sigler (1987) stated: "The trout-perch was introduced in Willard Bay Reservoir and Utah Lake, Utah in 1983." Apparently these introductions were successful and the species has become established in this state, for Sigler and Sigler (1996) continued to list this species as present in Utah.
Migration
May migrate between lake and spawning stream (Scott and Crossman 1973).
Habitat
Typically in lakes but also in deep flowing pools of creeks and small to large rivers; usually over sand (Page and Burr 1991). Normally in deep waters by day, moves into shallows at night (Becker 1983). Spawns in shallow rocky or gravelly streams or over sand or gravel bars or among rocks in lakes. Often spawns in streams in spring and returns to lake after spawning.
Food habits
Young feed on zooplankton to greater extent than do larger fishes, which feed on insects, crustaceans, and other invertebrates, mainly benthic species. Larger individuals may feed on fishes in winter (Scott and Crossman 1973, Becker 1983).
Reproductive characteristics
Usually spawns in spring, but spawning may extend into late summer in some lakes. Most spawners are age I or II (Becker 1983, Scott and Crossman 1973).
Threats or limiting factors
On a range-wide scale no major threats are known. In the southern part of the range, degradation of lakes and streams has negatively affected distribution and abundance. Trout-perch are especially sensitive to aquatic pollution and sedimentation associated with row crop agriculture and channelization (Pflieger 1997). Fish exposed to pulp mill effluent on the Kapuskasing River, Ontario, showed a change in age structure that was likely driven by an increase in mortality (Gibbons et al. 1998). This species may also be temperature sensitive; summer die-offs in Minnesota lakes have been attributed to higher than average temperatures (Eddy and Underhill 1974). A marked decline in the Red Deer River, Alberta trout-perch population was attributed to the impacts of a dam built there (Nelson, pers. comm., in Bramblett 2005).
References
- Biotics Database. 2005. Utah Division of Wildlife Resources, NatureServe, and the network of Natural Heritage Programs and Conservation Data Centers.
