Abstract:
The use of biologging instruments has greatly improved our understanding of
the behaviour, physiology and ecology of free-ranging marine mammals.
However, handling wild animals and attaching instruments to streamlined
bodies can cause stress and potentially influence behaviour and swimming/
diving energetics. The goals of this study, undertaken on Bouvetøya, were (1)
to determine if the first trip to sea after instrumentation is representative of
subsequent trips in lactating Antarctic fur seals, to explore potential handling
effects and assess possible biases in having multiple short-duration deployments
(inflating N, using a limited number of tags) and (2) to evaluate
potential effects of two different instrument combinations (SMRU satellite data
relay loggers and very high frequency radio transmitters versus Wildlife
Computers time depth recorders and very high frequency radio transmitters)
on trip durations, dive parameters, female body condition and pup growth.
Handling did not appear to have any effects on the parameters studied; data
from the first and second trips did not differ significantly. This implies that
multiple short-term deployments are unlikely to result in biased data in this
species. Instrument type did have measurable effects; time-at-sea was greater
and pup growth was lower for pairs in which mothers carried bulkier
instruments. This suggests that instrument streamlining is important to avoid
negative impacts and that bulkier equipment should be deployed on lactating
females with caution and only for short periods. The study highlights that
instrument effects should be taken into account when comparing data from
experiments collected using different equipment packages.
