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The high variability in reported lengths of larval yellow perch Perca flavescens at hatching, dietary shift, and morphometric transformation may be partly caused by shrinkage that occurs after preservation. Larval yellow perch were captured, randomly assigned to one of six preservative treatments (100%, 95%, 80%, and 50% ethyl alcohol and 5% and 10% formalin), and measured (before preservation) for total length (TL). Larval yellow perch total lengths were then recorded on days 1, 7, 14, and 21 after storage in each of the six preservatives. Significant reductions in TL (11.5–14.3%) occurred during the first 24 h after fixation and larvae continued to contract at a lesser rate through day 7 in all four ethyl alcohol treatments. Total length reductions of up to 2.5% also occurred during the first 24 h in each formalin concentration. Our findings report the total length reductions of larval yellow perch at a length range used by some biologists when indexing year-class strength and during studies of...

We sought to determine if abundance of larval yellow perch Perca flavescens could predict abundance of age-0 juvenile perch in late summer. Yellow perch larvae and juveniles were sampled from six eastern South Dakota glacial lakes in 1997. The number of age-0 yellow perch caught per seine haul in late summer was positively related to larval abundance in late May and early June (N = 6, r = 0.90, P = 0.01). When data collected from two eastern South Dakota lakes in 1995 and 1996 were added to this assessment, we also found a significant positive relation (N = 10, r = 0.88, P = 0.0009). Thus, biologists in eastern South Dakota can use larval yellow perch abundance as an early indicator to determine which water bodies are likely to have a weak naturally produced year-class and then can evaluate the success of fingerling perch stocking strategies.