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Fishery Bulletin 115(3) 
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Figure 3 
Examples of the 3 behavior types, or patterns of vertical movement, during day and night, of 
oceanic whitetip sharks ( Carcharhinus longimanus ) identified by visual assessments of depth 
data from sharks tagged in the Atlantic and Indian oceans between 2011 and 2012: (A) type-I, 
(B) type-II, and (C) type-III behavior. 
! 
( 
( 
[ 
i 
served during June-July and early May, respectively, 
than during other periods. The observation of higher SD 
values coincided with a larger mixed layer, indicating 
that oceanic whitetip sharks have a greater depth range 
when their preferred environment is expanded. Sea-sur- 
face temperature also appears to influence vertical be- 
havior. Careful inspection of Figure 6 for sharks AOCS3, 
AOCS6, and AOCS7 reveals that these individuals ex- 
plored colder waters during periods of higher SST. 
To better understand the influence of environmen- 
tal conditions on the vertical behavior of the oceanic 
whitetip sharks in this study, several GAMs were ap- 
plied. The results from these models were in accor- 
dance with the patterns in daily temperature-at-depth 
profiles estimated from tag data and depth SDs pre- > 
sented in Figure 6. The best models consistently in- 
dicated a significant influence of horizontal position 
(longitude and latitude), MLD, and SST on daily verti- 
cal activity (SD of daily depth records). Results from ! 
the model with combined data from all sharks indicate 
an additional effect of shark size and explain 50.1% ’ 
of the deviance (coefficient of multiple determination 
[i? 2 ] =0.48, n=685). Results from this model indicate an 
increase of vertical amplitude with the increase of the 
MLD and shark size. Sea-surface temperature follows 
the same trend, but it was the least significant factor " 
