As part of the Landscape Position Project, yellow perch were collected for mercury and isotope analysis by a combination of angling, beach seining, vertical gill net, fyke net and electrofishing in the summers of 1998 and 1999. A total of 183 yellow perch from 43 study lakes with approximate length of 150 mm were analyzed. Sampling Frequency: one survey on each lake in late June through August of 1998 or 1999 Number of sites: 43