A METHOD FOR ESTIMATING MASS OF LARGE PINNIPEDS

Fifty-two male elephant seals were weighed and photographed at Ano Nuevo State Reserve, California, to establish a predictive relationship between photographically measured morphological variables (length, side area, and girth area) and body mass. Regression of mass on these variables revealed that side area, roughly equivalent to a longitudinal cross-section, was the most useful single variable for predicting mass, and that adding the other two variables to side area slightly improved the accuracy of the photogrammetric technique. Curvi-linear regressions based on a power model provided the best predictive relationships. This technique may prove useful for estimating body mass of other pinnipeds.