Structure and Stability of the Midsummer Fish Communities in Chequamegon Bay, Lake Superior, 1973–1996

Abstract

Abstract We analyzed the structure and stability of the summer fish communities of Chequamegon Bay, Lake Superior, during 1973–1996 from data collected with bottom trawls at 39 stations. Fifty-three taxa were collected during the study, but we found that relative abundances for 20 taxa described most of the internal variability of the data for all taxa. Abundance data for the 20 species showed that two communities existed in the bay; one inhabited shallow water (≤3.0 m) whereas the other inhabited deeper water (>3.0 m). No temporal patterns of change were found in the structure of the shallow-water community, whose variation was best described by abundances of 12 taxa. The deepwater community, whose variation was best described by eight taxa, underwent three periods ofstability; 1973–1978, 1979–1988, and 1989–1996. We conclude that the shallow-water community was stable throughout the 24 years studied. Dynamics of the deepwater community were greatly affected by changes in stocking rates of lake trout Sal...