Habitat use and recruitment: a comparison of long-term recruitment patterns among fish species in a shallow eutrophic lake, Oneida Lake, NY, U.S.A.

We analyzed inter-annual patterns in first-year abundance of 11 fishspecies in Oneida Lake, New York, USA, using trawl data collected from 1961 to 1997. We found two major recruitment patterns among the 11species. One group (yellow perch, walleye, logperch and tessellated darter) decreased in abundance after the mid-1980s. These species arespring or early summer spawners with benthic juveniles. In the second group, most species increased during the early to mid 1980s (smallmouth bass, trout-perch, white bass, gizzard shad and freshwater drum), while two recruited episodically (white perch and pumpkinseed). These species spawned later than the first group and juvenile habitat use was variable. We investigated three specific mechanisms which couldexplain these patterns (1) competition with young-of-year (YOY) yellow perch, the dominant fish species in the lake, (2) buffering of predation by walleye by YOY yellow perch, and (3) correlation with watertemperature and productivity (indexed through total phosphorus levels, TP). Buffering from predation by walleye was likely important for the species in the first group, as indicated by positive correlationsbetween inter-annual abundance patterns of the four species. Even though species in the second group tended to increase as YOY yellow perch declined, we found little support for the competition hypothesis. Growth and abundance of these species were not significantly correlated with abundance of YOY yellow perch. Temperature was positively correlated with growth of 10 of the 11 species. Decreasing TP levels andassociated changes in the lake could be causing a shift in the fish community, but the mechanism is not decreased food production. Pelagic zooplankton abundance, a direct link from nutrients to YOY fish production, has not declined since 1975. [ABSTRACT FROM AUTHOR]