Measurement of the range and relative proportions of morphological characters of an organism, commonly used in the scientific description of a species. In fish, for example, morphometrics often include the ratio of predorsal length to the standard length or the ratio of body depth to the standard length. Ratios are almost always preferred to absolute measurements since they remove significant variation due to size. However, some ratios may pose problems because of allometry in growth: juveniles may be more slender. (Yes, it happens in fish, too.)