Musyl et a!.: Postrelease survival, vertical and horizontal movements, and thermal habitats of five species of pelagic sharks 
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Day Night 
Figure 3 
Daytime and nighttime depth and thermal ranges for pelagic species: bigeye 
thresher (Alopias superciliosus), blue shark (Prionace glauca), shortfin mako 
( Isurus oxyrinchus), silky shark ( Carcharhinus falciformis), oceanic whitetip 
shark (C. longimanus ), bigeye tuna ( Thunnus obesus), and swordfish (Xiphias 
gladius). The box represents the interquartile range. The position of the mean 
(dashed horizontal line) and median (solid horizontal line) are indicated and the 
“whiskers” represent the 10-90 th deciles. M=male and F=female. 
Grouping of vertical movement patterns 
Kruskal-Wallis ANOVAs showed that medians of depth 
and temperature data across individuals for each pelagic 
shark species (24 total tests) were all significantly differ- 
ent for the six PSAT data streams, indicating substantial 
amounts of individual variability in vertical movement 
patterns (Appendix 3). This result was confirmed by 
post-hoc pairwise MWBC tests (Appendix 3). Signifi- 
cantly different daytime and nighttime median depths 
and temperatures (DD vs. ND, DT vs. NT) were evident 
in most pooled comparisons (including those by sex) and 
in the majority of comparisons within and between indi- 
viduals. Results from two-sample KS tests for each of the 
pelagic shark samples paralleled the results given for the 
MWBC tests. For the entire sample of 394 possible two- 
sample KS tests in which depth distributions between 
individuals were compared, 94% of tests were signifi- 
cantly different. And of 394 possible tests for temperature 
comparisons, 98% of tests were significantly different. 
Although individuals exhibited high levels of variabil- 
ity, we were able to partition shark species into three 
major groups based on daytime temperature preferences 
by using UPGMA clustering with the Z) max distance 
(Fig. 8). These were 1) epipelagic species that included 
silky sharks and oceanic whitetip sharks, plus the out- 
groups black marlin and blue marlin; 2) mesopelagic-I 
species that included blue sharks and shortfin makos; 
