Fig 4. (a) Log-log relations between dominant tail beat frequency (TBF, Hz) as predictor and length (m) for saithe (solid circles, n = 18) and sturgeon (open triangles, n = 22) showing ordinary least square regressions (solid line) bracketed by the 95% confidence intervals around the regression (dashed lines) and predictions (dotted lines), and (b) prediction uncertainties, P _U as a function of length (m) for saithe (sold line) and sturgeon (dashed line) expressed as P _U = 100 t _0.975,n-2 SE _lp/l _p where lp is the model prediction and SE _lp is the associated standard error for the prediction.