Determining Blubber Mass in the Southern Elephant Seal, Mirounga-Leonina, by Ultrasonic and Isotopic Techniques

Abstract

The mass of subcutaneous fat was determined for 14 male southern elephant seals, Mirounga leonina, by a modified version of a previously described ultrasound model (Gales and Burton 1987). The new model took into account fat slumping and was more accurate than the first model. The accuracy of the new technique was assessed by flensing. Total body water was estimated by tritiated-water dilution, and the relationship between total body water and ultrasonically determined total blubber mass was established. Predictive relationships for total blubber mass, and the relationship between total blubber mass and total body fat were determined. This study has demonstrated the applicability of ultrasound and isotope-dilution techniques in determining the fat composition in vivo of southern elephant seals.