Measuring changes in juvenile grey seal body composition

Determining body composition in gray seals (Halichoerus grypus) is important when studying their physiology and life history. In this study we investigated the predictability of total body fat (TBF) and protein (TBP) in postweaned gray seal pups from morphometric measurements, blubber thickness usin...

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Bibliographic Details
Published in:Marine Mammal Science
Main Authors: Hall, Ailsa Jane, McConnell, Bernie J
Format: Article in Journal/Newspaper
Language:English
Published: 2007
Subjects:
gray seal
Halichoerus grypus
total body fat
total body protein
isotope dilution
ultrasound
BIA
survival
BIOELECTRICAL-IMPEDANCE ANALYSIS
SOUTHERN ELEPHANT SEAL
ANTARCTIC FUR SEALS
MIROUNGA-LEONINA
BLUBBER THICKNESS
HARBOR SEAL
PHOCA-VITULINA
WEANING MASS
GREY SEALS
PUPS
Antarctic
Bia
Antarc*
Antarctic Fur Seals
Elephant Seal
harbor seal
Mirounga leonina
Phoca vitulina
Southern Elephant Seal
Online Access:https://risweb.st-andrews.ac.uk/portal/en/researchoutput/measuring-changes-in-juvenile-grey-seal-body-composition(2f06bd13-ba1f-436c-8b9b-f3bda357d1bb).html
https://doi.org/10.1111/j.1748-7692.2007.00132.x
http://www.scopus.com/inward/record.url?scp=34250332280&partnerID=8YFLogxK
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Summary:Determining body composition in gray seals (Halichoerus grypus) is important when studying their physiology and life history. In this study we investigated the predictability of total body fat (TBF) and protein (TBP) in postweaned gray seal pups from morphometric measurements, blubber thickness using ultrasonographs and bioelectrical impedance analysis (BIA). In postweaned pups, TBF (kg) could be estimated from girth measurements and sex (n = 45, r(2) = 0.878) using hydrogen isotope dilution methods as the reference. However, TBP could not be reliably estimated from morphometric data. TBF (kg) in yearlings was best predicted from mass (n = 6, r(2) = 0.776) and TBP (kg) from mass/length (r(2) = 0.949). Dorsal blubber thickness using B-mode ultrasound was also a significant predictor of TBF (kg) in postweaned pups (r(2) = 0.725) but BIA was not. Marked pups were recaptured during their first few months of life (n = 48) and body composition changes investigated. Animals lost mass and TBF after leaving the breeding beach, largely during the first 5-6 mo of life. Postweaned pups were similar to 40% TBF and similar to 13% TBP whereas yearlings were similar to 12% TBF and similar to 20% TBP. Pups that survived beyond 6 mo of age then regained mass as protein. Morphometric measurements are a useful field indication of body condition when isotope dilution is impractical.

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