TY - JOUR
T1 - Estimation of body volume and body density in California sea lion pups
AU - Luque, Sebastián P.
AU - Aurioles-Gamboa, David
PY - 2002/12
Y1 - 2002/12
N2 - Body volume was measured directly by the water displacement method and using three different geometric models, consisting of a series of cones and truncated cones, in California sea lion (Zalophus californianus) pups from the Gulf of California. Volume is required for the estimation of density, an indicator of the ratio of fat to lean mass. A model consisting of two cones and four truncated cones predicted body volume with greatest accuracy (volume=1.11+1.06 × estimated volume, r2=0.90, P<0.001, SEE=0.673, N=274). This model, however, was not adequate to estimate absolute pup body density (mass to volume ratio), as it yielded values poorly correlated with observed body density (r=0.14, P=0.02). However, the regression line of mass on volume indicated that density decreased with volume, so the mass to volume ratio is a biased estimate of density and is not appropriate for comparing whole body density among sea lion pups. The direct analysis of the relationship between body mass and body volume (observed or estimated) through analysis of covariance provided a better tool to compare the relative density among pups of different sex, populations, or born in different years. The results from such analyses are consistent with previous evidence of sex and age effects on body composition.
AB - Body volume was measured directly by the water displacement method and using three different geometric models, consisting of a series of cones and truncated cones, in California sea lion (Zalophus californianus) pups from the Gulf of California. Volume is required for the estimation of density, an indicator of the ratio of fat to lean mass. A model consisting of two cones and four truncated cones predicted body volume with greatest accuracy (volume=1.11+1.06 × estimated volume, r2=0.90, P<0.001, SEE=0.673, N=274). This model, however, was not adequate to estimate absolute pup body density (mass to volume ratio), as it yielded values poorly correlated with observed body density (r=0.14, P=0.02). However, the regression line of mass on volume indicated that density decreased with volume, so the mass to volume ratio is a biased estimate of density and is not appropriate for comparing whole body density among sea lion pups. The direct analysis of the relationship between body mass and body volume (observed or estimated) through analysis of covariance provided a better tool to compare the relative density among pups of different sex, populations, or born in different years. The results from such analyses are consistent with previous evidence of sex and age effects on body composition.
UR - http://www.scopus.com/inward/record.url?scp=0036961324&partnerID=8YFLogxK
U2 - 10.1017/S0025315402006550
DO - 10.1017/S0025315402006550
M3 - Artículo
SN - 0025-3154
VL - 82
SP - 1019
EP - 1022
JO - Journal of the Marine Biological Association of the United Kingdom
JF - Journal of the Marine Biological Association of the United Kingdom
IS - 6
ER -