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Figure 1 
(A-D) Maps showing the tracks of 4 leatherback turtles (Dermochelys coriacea) equipped with satellite tags follow- 
ing incidental entanglement in fishing gear off Nova Scotia, Canada, during 2003-2012. The dashed line indicates 
the 1000-m isobath. 
which are normally impossible to diagnose remotely, make 
it difficult to identify events of true turtle mortality, espe- 
cially when environmental data, such as depth, tempera- 
ture, or light level, are not available. 
Uncertainty regarding how representative the sample 
we considered is of post-entanglement outcomes for leath- 
erbacks results from the relatively low number of entan- 
gled turtles equipped with satellite tags and the lack of 
standardized biomedical assessment criteria for classifying 
entanglement condition across all turtles. Innis et al. (2010) 
and Dodge et al. (2014) deliberately included turtles 
with apparent entanglement injuries in their studies, 
and an attending veterinarian conducted detailed ani- 
mal health assessments. Comparable assessments were 
not available for the sample from Canada. Therefore, it is 
possible that the results from Canada may reflect biases 
associated with turtles that, although entangled, appeared 
relatively healthy at the time of tagging. This is possible 
because, to meet animal care permitting requirements, 
only turtles that appeared active and responsive were 
equipped with satellite tags off Nova Scotia. 
The data presented here indicate that some leatherbacks 
survive entanglement events and complete long-distance 
migrations. However, opportunistic satellite tagging of 
entangled leatherbacks is logistically challenging. There- 
fore, to date, only small sample sizes have been achieved 
and under inconsistent study protocols. These limitations 
have precluded quantification of postrelease mortality of 
leatherbacks following bycatch in various fisheries. Tar- 
geted studies of fates of incidentally captured leather- 
backs at the time of release and after release are urgently 
required to effectively quantify the threat of incidental 
entanglement. Such research should apply standardized 
protocols for leatherback health assessment and should 
consider the role of different environmental conditions, 
gear types, and entanglement severity on fates of turtles. 
In the interim, survival outcomes for leatherbacks inter- 
acting with fisheries could be enhanced through efforts to 
reduce the duration of entanglement events. This may be 
accomplished through reduced soak times, regular checking 
of gear, and implementation of prompt and humane disen- 
tanglement protocols. 
