The blubber conductivity at site B was significantly
lower than that at sites A (P < 0.05) and D
(P < 0.005), and samples from site C had a conductivity
significantly lower than blubber from site D
(P < 0.005). Thermal conductivity varied by almost
a factor of two, from 0.18 Wrn-’ K-’ (site B) to
0.35 Wm-’ K-’ (site D), in the same animal. The
blubber of sites B and D was significantly thicker
than blubber from site C (P < 0.05). Blubber at
site B had the lowest thermal conductivity and was
also thickest, which resulted in a significantly higher
thermal resistance of the blubber at that site
(P < 0.05) compared with sites A, C and D (Table 1).
Assuming that the temperature difference across
the blubber is the same at all sites which were
sampled, this difference in thermal resistance would
imply that the heat loss rate per unit surface area
in the posterio-ventral region is very low compared
with the other sites. This is illustrated in Fig. 1,
where heat loss rates were calculated by assuming a
temperature difference across the blubber of 22°C
(Folkow and Blix, 1992).
The per cent water and lipid content of the blubber
with respect to the different sampling sites are given
in Table 1. From the present study, the following
relationships describing changes in blubber conductivity
as a function of lipid content, equation (3), and
water content, equation (4), were derived
The blubber conductivity at site B was significantlylower than that at sites A (P < 0.05) and D(P < 0.005), and samples from site C had a conductivitysignificantly lower than blubber from site D(P < 0.005). Thermal conductivity varied by almosta factor of two, from 0.18 Wrn-’ K-’ (site B) to0.35 Wm-’ K-’ (site D), in the same animal. Theblubber of sites B and D was significantly thickerthan blubber from site C (P < 0.05). Blubber atsite B had the lowest thermal conductivity and wasalso thickest, which resulted in a significantly higherthermal resistance of the blubber at that site(P < 0.05) compared with sites A, C and D (Table 1).Assuming that the temperature difference acrossthe blubber is the same at all sites which weresampled, this difference in thermal resistance wouldimply that the heat loss rate per unit surface areain the posterio-ventral region is very low comparedwith the other sites. This is illustrated in Fig. 1,where heat loss rates were calculated by assuming atemperature difference across the blubber of 22°C(Folkow and Blix, 1992).The per cent water and lipid content of the blubberwith respect to the different sampling sites are givenin Table 1. From the present study, the followingrelationships describing changes in blubber conductivityas a function of lipid content, equation (3), andwater content, equation (4), were derived
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