Due to the complications of using the labeled-water
dilution technique in a feeding seal, we feel that the
morphometric measurements are a more reliable measure
of body composition. On average, the mean body
composition measured by the two methods differed by
2.1% (morphometric method ¼ 37.673.4% blubber, labeled-
water dilution ¼ 35.776.1% blubber). At the individual
level, the percent body fat estimated by the
ultrasound/morphometric method overestimated that determined
by the labeled-water dilution method (mean
error ¼ 7.9715.8%, range ¼ 9.3% to 45.2%). However,
the results from the two methods were significantly
correlated (Fig. 3; Pearson correlation coefficient ¼ 0.72,
P ¼ 0.003) and not significantly different (paired t-test,
t14 ¼ 1.74, P ¼ 0.10).