Comparison of stable isotope data (δ¹³C, δ¹⁵N) of scale (open circle) and fin (filled circle) versus dorsal muscle for pumpkinseed (A, C) and European perch (B, D); solid lines = equality; small dashed line = significant relationship between fin and muscle SI data according to linear regression; long dashed line = significant relationship between fin and muscle SI data according to linear regression.