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Fishery Bulletin 1 12(4) 
Figure 4 
Postmortem temperatures indicating gradual cooling recorded for the mortality 
of one Steller sea lion (Eumetopias jubatus) by a life history transmitter (LHX 
tag) with delayed onset of transmission. Temperatures were recorded in 30-min 
increments by the single, abdominally implanted LHX tag. The event occurred 
in the Gulf of Alaska in 2008. The gray shaded area represents the 95% confi- 
dence interval from the output of the algor mortis model for a 146-kg animal 
(for details, see the Materials and methods section). Actual cooling rates were 
best described by an algor mortis model for a sea lion with a mass of 24 kg. The 
gray diamond indicates the regional estimate for sea-surface temperature (for 
sources, see Table 1). The arrow indicates that the tag sensed light or air and 
began to transmit only 16 d post mortem. 
of 7.55°C but did not sense light or air, and they did 
not commence transmissions until 5 and 9 d post mor- 
tem, respectively (Table 1; Fig. 5). The regional SST 
estimate of 4.97°C was more than 2°C below recorded 
postmortem temperatures, and it was closely matched 
by uplink temperatures of 5.22°C from 1 tag (5 d post 
mortem). The second tag was beached by the time of 
the first successful uplink (9 d post mortem) and re- 
ported air temperatures near freezing. 
The 2 tags from the remaining event (TJ63) record- 
ed disparate details that corresponded with type-I and 
-IV scenarios (Fig. 5). One tag (type I) recorded pre- 
cipitous temperature drops (peak AT: -0.94°C min -1 ) 
to 5.20°C, close to the regional SST estimate of 5.07°C 
(Table 1). This tag began making transmissions at the 
first opportunity after sensing air and light, reporting 
uplink temperatures of 5.73°C. The second tag (type 
IV), however, recorded a precipitous drop (peak AT: 
-0.90°C min -1 ) to 7.02°C. It started transmissions only 
6 d later, after sensing light or air, and reported tem- 
peratures of 5.13°C, a level close to the regional SST 
estimate of 4.73°C (Table 1). 
Pairs of LHX tags without disparate fates (as indicat- 
ed by light or air data) reported consistent postmortem 
temperatures: the mean difference within pairs (n=ll) 
was 0.15°C (SD 0.13), the maximum difference was 
0.5 1°C. Temperatures uplinked by tags free-floating at 
the sea surface also were consistent with regional SST 
estimates, with a mean difference within pairs (n=16) of 
0.32°C (SD 0.31). The mean difference between postmor- 
tem temperatures and SSTs for tags without delayed 
transmissions (n= 23) was 0.24°C (SD 0.21). However, 
the average (absolute) difference between regional SST 
estimates and postmortem temperatures reported by 4 
tags that showed both precipitous temperature drops 
and delayed transmissions was considerably higher at 
3.29°C (range: 1.95-6.05°C; Fig. 5). Each of these 4 tags 
also recorded postmortem temperatures that were ex- 
tremely constant, with maximum temperature fluctua- 
tions of 0.0°C, 0.2°C, 0.0°C, and 0.0°C over a period of 
