Ultrasonic Measurement of Blubber Thickness of the Southern Elephant Seal, Mirounga-Leonina (Linn)

Abstract

Ultrasound measurements of subcutaneous fat at 18 body sites on each of 23 southern elephant seals Mirounga leonina (Linn.), together with circumference and length measurements, were used to estimate the total subcutaneous blubber weight on each animal. Twelve cows (including animals that were pregnant and others at early, mid-, late and post-lactation), 10 males and one male pup were anaesthetised for these measurements, made at Heard I. (53�01'S.,73�23'E.) on various dates in October and November 1985. Comparison of the estimates of blubber weight from cows at various stages of lactation allowed a mean blubber loss of 62.8 kg per cow per lactation to be calculated. It is suggested that measuring variations in the subcutaneous fat reserves of cows coming ashore to pup at Heard I. may be one relevant approach in any future research that attempts to explain the 60% drop in pup production at that island between 1949 and 1985. The use of ultrasound to estimate the subcutaneous fat reserves of seals was shown to be a safe, non-invasive and logistically practical technique.

Age-related differences in skeletal muscle lipid profiles of Weddell seals: clues to developmental changes

“…Surface area, body volume (excluding flippers) and blubber volume were determined by standard geometric equations for a series of truncated cones following the methods of Gales and Burton (Gales and Burton, 1987). Blubber mass was calculated by multiplying blubber volume by the density of pinniped blubber (0.95gcm -3 ) (Gales and Burton, 1987). Simple linear regression was used to determine the relationship between IML and the relative contribution of each FA group (SFA, MUFA, PUFA) as a function of the percentage of body fat for each age class.…”

“…Diving phocids (true seals, Order Carnivora, Family Phocidae) must sequester adequate amounts of lipids to maintain sufficient blubber thickness to meet nutritional demands, buoyancy regulation and maintain thermoregulatory homeostasis (Burns et al, 2003;Castellini et al, 2009;Crocker et al, 1997;Gales and Burton, 1987;Kanatous et al, 2008;Noren et al, 2008;Rosen and Renouf, 1997;Ryg et al, 1988;Sato et al, 2003;Webb et al, 1998). Consequently, the selective pressures for maintaining blubber thickness are typically a combination of these demands, varying with age, diet and reproductive status (Castellini et al, 2009).…”

Impact of El Niño on the foraging behavior of female northern elephant seals

“…Dorsal, lateral, and ventral blubber thickness, length and girth were measured at 6 locations along the seal's long axis. Based on these measurements, body composition was estimated for each female using the truncated cones method (Gales & Burton 1987, Webb at al. 1998, Le Boeuf et al 2000.…”

Lipolysis and glycerol gluconeogenesis in simultaneously fasting and lactating northern elephant seals

“…Body mass was measured by weighing females from a tripod with a 1,000 Ϯ 2 kg suspension scale (MSI tension dynamometer, Seattle, WA) and levered hand winch. Body composition was determined for each subject by using the morphometric data to model the seal as a series of truncated cones (20). This method of determining body composition has been validated extensively in elephant seals through 3 H2O dilution techniques and yields a mean absolute error in lipid content of adult females of ϳ3% (40).…”