106
Colleye et al. 2013 ). Myoxocephalus sounds are associated with obvious vibrations of
the pectoral girdle when handled (Fish and Mowbray 1970 ), and an electromyography
study found that cranioclavicular muscles contract in association with sound production in Myoxocephalus octodecemspinosus (Barber and Mowbray 1956 ). In Cottus
spp., behavioural observations support a similar cranio-pectoral muscle mechanism;
head abduction and/or pectoral girdle adduction have been observed repeatedly in
association with sounds (Ladich 1989 ; Kierl and Johnston 2010 ; Colleye et al. 2013 ).
The levator pectoralis is a candidate muscle that could generate a forward displacement of the pectoral girdle in Cottus spp. (Colleye et al. 2013 ).
The levator pectoralis muscles of Gobius paganellus are contracted during sound
production (Parmentier et al. 2013 ). These muscles exhibit ribbon-like myofi bril
structure, a mitochondria dense core, and well-developed sarcoplasmic tubules—
characteristics typically found in specialized sonic muscle (Parmentier et al. 2013 ).
In both Myoxocephalus and Gobius , muscles on both sides are contracted simultaneously, and the contraction rate is equal to the pulse repetition rate of the sound
produced (Bass and Baker 1991 ; Parmentier et al. 2013 ), as has been found more
broadly for sonic drumming mechanisms in fi shes (Ladich and Fine 2006 ). Sounds
were still produced after experimental defl ation of the swim bladder in Padogobius
bonelli , a species of goby possessing a swim bladder, suggesting the lack of a role
of the swim bladder in sound production for this species (Lugli et al. 2003 ).
Hydrodynamic expulsion of water through the gills was proposed by Tavolga
( 1958 ) as a sound production mechanism for Bathygobius , which was supported in
a separate study by the similar sound structure produced by the expulsion of water
from a loaded pipette underwater (Stadler 2002 ). Such a forced water expulsion
mechanism was not supported in Gobius paganellus , since experimentally cutting
the opercula and hyohyoideus muscle, which would prevent water retention and
forceful expulsion from the buccal cavity, did not eliminate sound production
(Parmentier et al. 2013 ). Presently, no attempts have been made to investigate the
mechanics of sound production in darters, but our observations of “head nodding”
movements during sound production in Etheostoma corona (DEH, unpublished)
point to a similar cranial-pectoral muscle contraction.
4 Audiograms
These fi shes have reduced or absent swim bladders, thus limiting or preventing any
hearing enhancement via pressure sensitivity (Popper and Fay 1993 , 2011 ). In
gobies that do possess a swim bladder, it does not appear to play a signifi cant role
in sound detection. As a group, the auditory sensitivities of gobies possessing a
swim bladder (i.e. Padogobius bonelli , Pomatoschistus minutus , and Gobius cruentatus ) do not differ signifi cantly from those lacking it (i.e. Neogobius melanostomus
and Padogobius nigricans ). Additionally, experimentally puncturing the swim bladder of P. bonelli did not affect auditory sensitivity (Lugli et al. 2003 ).
J.N. Zeyl et al.
Colleye et al. 2013 ). Myoxocephalus sounds are associated with obvious vibrations of
the pectoral girdle when handled (Fish and Mowbray 1970 ), and an electromyography
study found that cranioclavicular muscles contract in association with sound production in Myoxocephalus octodecemspinosus (Barber and Mowbray 1956 ). In Cottus
spp., behavioural observations support a similar cranio-pectoral muscle mechanism;
head abduction and/or pectoral girdle adduction have been observed repeatedly in
association with sounds (Ladich 1989 ; Kierl and Johnston 2010 ; Colleye et al. 2013 ).
The levator pectoralis is a candidate muscle that could generate a forward displacement of the pectoral girdle in Cottus spp. (Colleye et al. 2013 ).
The levator pectoralis muscles of Gobius paganellus are contracted during sound
production (Parmentier et al. 2013 ). These muscles exhibit ribbon-like myofi bril
structure, a mitochondria dense core, and well-developed sarcoplasmic tubules—
characteristics typically found in specialized sonic muscle (Parmentier et al. 2013 ).
In both Myoxocephalus and Gobius , muscles on both sides are contracted simultaneously, and the contraction rate is equal to the pulse repetition rate of the sound
produced (Bass and Baker 1991 ; Parmentier et al. 2013 ), as has been found more
broadly for sonic drumming mechanisms in fi shes (Ladich and Fine 2006 ). Sounds
were still produced after experimental defl ation of the swim bladder in Padogobius
bonelli , a species of goby possessing a swim bladder, suggesting the lack of a role
of the swim bladder in sound production for this species (Lugli et al. 2003 ).
Hydrodynamic expulsion of water through the gills was proposed by Tavolga
( 1958 ) as a sound production mechanism for Bathygobius , which was supported in
a separate study by the similar sound structure produced by the expulsion of water
from a loaded pipette underwater (Stadler 2002 ). Such a forced water expulsion
mechanism was not supported in Gobius paganellus , since experimentally cutting
the opercula and hyohyoideus muscle, which would prevent water retention and
forceful expulsion from the buccal cavity, did not eliminate sound production
(Parmentier et al. 2013 ). Presently, no attempts have been made to investigate the
mechanics of sound production in darters, but our observations of “head nodding”
movements during sound production in Etheostoma corona (DEH, unpublished)
point to a similar cranial-pectoral muscle contraction.
4 Audiograms
These fi shes have reduced or absent swim bladders, thus limiting or preventing any
hearing enhancement via pressure sensitivity (Popper and Fay 1993 , 2011 ). In
gobies that do possess a swim bladder, it does not appear to play a signifi cant role
in sound detection. As a group, the auditory sensitivities of gobies possessing a
swim bladder (i.e. Padogobius bonelli , Pomatoschistus minutus , and Gobius cruentatus ) do not differ signifi cantly from those lacking it (i.e. Neogobius melanostomus
and Padogobius nigricans ). Additionally, experimentally puncturing the swim bladder of P. bonelli did not affect auditory sensitivity (Lugli et al. 2003 ).
J.N. Zeyl et al.