Size and distribution of oxygen stores in harp and hooded seals from birth to maturity

• Published in: Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology Biochemical, systemic, and environmental physiology, 2007-08, Vol.177 (6), p.687-700
• Main Authors: Burns, J. M, Lestyk, K. C, Folkow, L. P, Hammill, M. O, Blix, A. S
• Format: Article
• Language: English
• Subjects: Adults; Age Factors; Animals; Animals, Newborn - blood; Animals, Suckling - blood; Blood; Blood Chemical Analysis - veterinary; Blood volume; Body Composition; Body Size; Cross-Sectional Studies; Cystophora cristata; Diving - physiology; Erythrocyte Indices - veterinary; Female; Hematologic Tests - methods; Hematologic Tests - veterinary; Hemoglobins - metabolism; Hoods; Juveniles; Marine; Maturation; Muscle, Skeletal - metabolism; Muscles; Myoglobin - metabolism; Neonates; Nursing; Oxygen; Oxygen - blood; Oxygen - metabolism; Pinnipedia; Seals; Seals, Earless - blood; Seals, Earless - growth & development; Seals, Earless - physiology; Species Specificity; Stores
• ISSN: 0174-1578; 1432-136X
• DOI: 10.1007/s00360-007-0167-2

Pinnipeds rely primarily on oxygen stores in blood and muscles to support aerobic diving; therefore rapid development of body oxygen stores (TBO₂) is crucial for pups to transition from nursing to independent foraging. Here, we investigate TBO₂ development in 45 harp (Pagophilus groenlandicus) and 46 hooded (Cystophora cristata) seals ranging in age from neonates to adult females. We found that hooded seal adults have the largest TBO₂ stores yet reported (89.5 ml kg-¹), while harp seal adults have values more similar to other phocids (71.6 ml kg-¹). In adults, large TBO₂ stores resulted from large blood volume (harp169, hood 194 ml kg-¹) and high muscle Mb content (harp 86.0, hood 94.8 mg g-¹). In contrast, pups of both species had significantly lower mass-specific TBO₂ stores than adults, and stores declined rather than increased during the nursing period. This decline was due to a reduction in mass-specific blood volume and the absence of an increase in the low Mb levels (harp 21.0, hood 31.5 mg g-¹). Comparisons with other phocid species suggests that the pattern of blood and muscle development in the pre- and post-natal periods varies with terrestrial period, and that muscle maturation rates may influence the length of the postweaning fast. However, final maturation of TBO₂ stores does not take place until after foraging begins.