Pearson et al. (1992)
reported similar behaviours in captive
rockfish (
Sebastes
spp.) at 180 dB re 1
l
Pa mean peak. Converting
the sound exposure levels (SEL) used in this study to mean peak
values, using factors derived and outlined in
McCauley et al.
(2000)
, places the change in behaviours observed in this study at
168–173 dB re 1
l
Pa mean peak. This is lower than the noise levels
required to induce alarm responses in the rockfish used in
Pearson
et al. (1992)
. However, after extrapolation of their results it was
suggested that ‘subtle’ changes in behaviour, such as the vertical
position in water column, could occur at 161 dB re 1
l
Pa mean
peak which is comparable to the results of the present study. The
differences in results between these, and other studies, could be
caused by factors such as differences in behavioural definitions,
species, cage size and acclimation procedures (in
Pearson et al.
(1992)
the experimental fish were wild caught and transferred into
the cages one day prior to the trials) or because of the approach-
depart air gun regime used in the present study as opposed to
the stationary air gun used by
Pearson et al. (1992)
.