266
coupled with anterograde and retrograde tracing to better understand how and
where ear and lateral line afferents are integrated at a central level.
2. While there have been some attempts to isolate ear and lateral line inputs by
selective ablation, especially of lateral line inputs (see above), more could be
done in this regard. We echo Zeddies et al. ( 2012 ) suggestion that selective ablation of each input in freely behaving fi sh would be highly instructive in determining the role of each system. While selective ablation is not without controversy
(Janssen 2000 ; Brown et al. 2011 ), if done carefully this technique can add
insights into how fi sh perceive stimuli and how this perception drives responses.
3. While challenging, more effort must be put into physiological and behavioural
responses in animals in their natural environment. At least for larger fi sh it is now
possible to accurately track movements of free-swimming fi sh with either
implanted passive integrated transponder (PIT) tags (e.g. www.Biomark.com ) or
acoustic tags (e.g. www.vemco.com ) and these technologies could be effectively
used to record responses of fi sh to a variety of sound stimuli. There has also been
rapid progress in side-scan sonar applications from many companies that provide
impressive details on fi sh movements and behaviours. Physiologically, it is now
possible to record from neurons of free-swimming fi sh (e.g. Radford and
Mensinger 2014 ) so more effort in this regard would be highly instructive as to
how fi sh process sensory stimuli at both peripheral and central levels, although
current technology would limit this to larger, more robust fi sh.
Acknowledgements Drs. Arthur Popper and Richard Fay have been the guiding infl uence for
much of the fi eld of fi sh bioacoustics throughout their careers and have advanced the fi eld by their
own primary research work as well as by the numerous commentary papers and compendia they
have put together over the years. Art was a valued mentor for DH during a critical phase of his
scientifi c career and acted as a true mentor as a scientist and as an academic. The time spent in
Popper’s lab continues to infl uence DH and contribute to his approach to science and mentoring.
Dr. Fay was also an important sounding board for DH during his time as a postdoctoral fellow and,
while DH never had the opportunity to work directly in Fay’s lab he always appreciated the feedback and assistance when their paths crossed. While CR has not had the opportunity to work
directly with either of Dr. Popper or Fay, they have really provided the foundation behind his work
in understanding how larval marine fi sh use underwater sound as an orientation cue. In saying that,
Dr. Popper has always supported CR’s work through invitations and support to attend
conferences.
The authors also gratefully appreciate the work of Ms. Meghan Donovan for drawing images for
Figs. 3 and 4 , Mr. Peter Johnston (MD) for the work on the CT-Scan images and two anonymous
reviewers for many constructive comments on an earlier draft of this manuscript.
References
Akamatsu T, Okumura T, Novarini N, Yan HY (2002) Empirical refi nements applicable to the
recording of fi sh sounds in small tanks. J Acoust Soc Am 112:3073–3082
Amorim MCP, Vasconcelos RO (2008) Variability in the mating calls of the Lusitanian toadfi sh
Halobatrachus didactlyus : cues for potential individual recognition. J Fish Biol
73:1267–1283
D.M. Higgs and C.A. Radford
coupled with anterograde and retrograde tracing to better understand how and
where ear and lateral line afferents are integrated at a central level.
2. While there have been some attempts to isolate ear and lateral line inputs by
selective ablation, especially of lateral line inputs (see above), more could be
done in this regard. We echo Zeddies et al. ( 2012 ) suggestion that selective ablation of each input in freely behaving fi sh would be highly instructive in determining the role of each system. While selective ablation is not without controversy
(Janssen 2000 ; Brown et al. 2011 ), if done carefully this technique can add
insights into how fi sh perceive stimuli and how this perception drives responses.
3. While challenging, more effort must be put into physiological and behavioural
responses in animals in their natural environment. At least for larger fi sh it is now
possible to accurately track movements of free-swimming fi sh with either
implanted passive integrated transponder (PIT) tags (e.g. www.Biomark.com ) or
acoustic tags (e.g. www.vemco.com ) and these technologies could be effectively
used to record responses of fi sh to a variety of sound stimuli. There has also been
rapid progress in side-scan sonar applications from many companies that provide
impressive details on fi sh movements and behaviours. Physiologically, it is now
possible to record from neurons of free-swimming fi sh (e.g. Radford and
Mensinger 2014 ) so more effort in this regard would be highly instructive as to
how fi sh process sensory stimuli at both peripheral and central levels, although
current technology would limit this to larger, more robust fi sh.
Acknowledgements Drs. Arthur Popper and Richard Fay have been the guiding infl uence for
much of the fi eld of fi sh bioacoustics throughout their careers and have advanced the fi eld by their
own primary research work as well as by the numerous commentary papers and compendia they
have put together over the years. Art was a valued mentor for DH during a critical phase of his
scientifi c career and acted as a true mentor as a scientist and as an academic. The time spent in
Popper’s lab continues to infl uence DH and contribute to his approach to science and mentoring.
Dr. Fay was also an important sounding board for DH during his time as a postdoctoral fellow and,
while DH never had the opportunity to work directly in Fay’s lab he always appreciated the feedback and assistance when their paths crossed. While CR has not had the opportunity to work
directly with either of Dr. Popper or Fay, they have really provided the foundation behind his work
in understanding how larval marine fi sh use underwater sound as an orientation cue. In saying that,
Dr. Popper has always supported CR’s work through invitations and support to attend
conferences.
The authors also gratefully appreciate the work of Ms. Meghan Donovan for drawing images for
Figs. 3 and 4 , Mr. Peter Johnston (MD) for the work on the CT-Scan images and two anonymous
reviewers for many constructive comments on an earlier draft of this manuscript.
References
Akamatsu T, Okumura T, Novarini N, Yan HY (2002) Empirical refi nements applicable to the
recording of fi sh sounds in small tanks. J Acoust Soc Am 112:3073–3082
Amorim MCP, Vasconcelos RO (2008) Variability in the mating calls of the Lusitanian toadfi sh
Halobatrachus didactlyus : cues for potential individual recognition. J Fish Biol
73:1267–1283
D.M. Higgs and C.A. Radford