Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 7437
Title: Living in the Fast Lane: Rapid development of the locomotor muscle in immature harbor porpoises (Phocoena phocoena)
Author: S. R. Noren, D. P. Noren, J. K. Gaydos
Publication Year: 2014
Journal: Journal of Comparative Physiology, B
Volume: 184
Issue: 8
Pages: 1065-1076
DOI: DOI 10.1007/s00360-014-0854-8
Keywords: Cetacean, Odonotocete, porpoise, myoglobin, buffering capacity, skeletal muscle, diving, swimming, development, aerobic, anaerobic,
Abstract:

 

Cetaceans (dolphins and whales) are born into
the aquatic environment and are immediately challenged
by the demands of hypoxia and exercise. This should promote
rapid development of the muscle biochemistry that
supports diving, but previous research on two odontocete
(toothed whales and dolphins) species showed protracted
postnatal development for myoglobin content and buffering
capacity. A minimum of 1 and 1.5 years were required
for Fraser’s (Lagenodelphis hosei) and bottlenose (Tursiops
truncatus) dolphins to obtain mature myoglobin contents,
respectively; this corresponded to their lengthy 2 and 2.5-
year calving intervals (a proxy for the dependency period
of cetacean calves). To further examine the correlation
between the durations for muscle maturation and maternal
dependency, we measured myoglobin content and buffering
capacity in the main locomotor muscle (longissimus
dorsi) of harbor porpoises (Phocoena phocoena), a species
with a comparatively short calving interval (1.5 years).
We found that at birth, porpoises had 51 and 69 % of adult
levels for myoglobin and buffering capacity, respectively, demonstrating greater muscle maturity at birth than that
found previously for neonatal bottlenose dolphins (10 and
65 %, respectively). Porpoises achieved adult levels for
myoglobin and buffering capacity by 9–10 months and
2–3 years postpartum, respectively. This muscle maturation
occurred at an earlier age than that found previously for
the dolphin species. These results support the observation
that variability in the duration for muscular development is
associated with disparate life history patterns across odontocetes,
suggesting that the pace of muscle maturation is
not solely influenced by exposure to hypoxia and exercise.
Though the mechanism that drives this variability remains
unknown, nonetheless, these results highlight the importance
of documenting the species-specific physiological
development that limits diving capabilities and ultimately
defines habitat utilization patterns across age classes.


 

Description:

investigated development of muscle myoglobin content and acid buffering capacity in harbor porpoise from Puget Sound region

Theme: Recovery and rebuilding of marine and coastal species
Foci: Develop methods to use physiological, biological and behavioral information to predict population-level processes.