Details:

Journal Title:
Conservation Physiology
Personal Author:
Walcott, Skyla M ; Kirkham, Amy L ; Burns, Jennifer M
Walcott, Skyla M ; Kirkham, Amy L ; Burns, Jennifer M Less -
NOAA Program & Office:
NMFS (National Marine Fisheries Service)
Description:
For polar marine mammals, the energetic cost of thermoregulation depends on ambient conditions in the highly variable surrounding environment. Heat conservation strategies used by pinnipeds to reduce total heat loss include small surface area to volume ratios, the ability to limit perfusion and thick subcutaneous blubber layers. There are limits to how cool the skin surface may remain without compromising function, especially during the annual pelage molt, when hair and skin are replaced. To determine if actively molting seals incur higher thermoregulatory costs, surface temperature (ST) and heat flux (HF) were measured in 93 adult female Weddell seals (Leptonychotes weddellii) both prior to and during the active molting period using direct sensors and infrared imaging. Linear mixed-effect models revealed that ST increased significantly with increased ambient temperature and decreased wind speed (contributing 44.6 and 41.7% of the attributed variance, respectively). Seal STs were not impacted by molt status, but were maintained at 11.2 +/- 0.3 degrees C warmer than the ambient temperature. Infrared imaging results averaged 15.1 +/- 1.4 degrees C warmer than direct ST measurements. In contrast, HF was significantly higher in seals in early molting stages compared to the pre-molt season (P<0.001) and molt status accounted for 66.5% of the variance in HF. Thermoregulatory costs calculated from estimated basal metabolic rate and measured HF were more than double for molting seals as compared to those in pre-molt. This suggests that perfusion is increased during molt to support follicle development, despite the increased energetic costs associated with higher HF rates. Because ST, HF and thermoregulatory costs are strongly influenced by ambient conditions, molt timing is likely under selective pressure to occur during the warmest period of the year. Shifts in environmental conditions that delay molt phenology or increase HF rates could negatively impact seal populations by further increasing thermoregulatory costs.
Keywords:
[+]
Biodiversity Climate-change Conditions Conservation Ecology Environmental Sciences Habitat Selection Harbor Seals Haul-out Behavior Heat Flux Mirounga-leonina Pack-ice Phoca-vitulina Physiology Pinniped Seals Solar Heat Gain Southern Elephant Seals Surface Temperature Thermal Thermoregulation Weather Windows
Source:
Conservation Physiology, Volume 8, Issue 1, 2020, coaa022, https://doi.org/10.1093/conphys/coaa022
DOI:
https://doi.org/10.1093/conphys/coaa022
Pubmed ID:
32274067;32913662;
Pubmed Central ID:
PMC7474932
Document Type:
Journal Article
Funding:
Permit no. 17411
Rights Information:
CC BY
Compliance:
PMC
Main Document Checksum:
[+]
urn:sha256:12cc23c7356fb033e21bebbedc32c37181d0d5130a2af1f9344fec9e22962a75
Download URL:
https://repository.library.noaa.gov/view/noaa/29259/noaa_29259_DS1.pdf
File Type:

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