335
have an intermediate hearing ability in terms of frequency bandwidth but not in
absolute thresholds between 0.1 and 5 kHz (Tavolga and Wodinsky 1963 ) (Fig. 12a,
b ). Surprisingly, members of the genus Sargocentron differ considerably (up to 30
dB) in sensitivity, potentially refl ecting swim bladder morphology differences (note
that only physiological but no morphological data are available for S. vexillarius
and S. xantherythrus ) or differences in threshold determination between labs (for
methodological differences see Hawkins 1981 ; Ladich and Wysocki 2009 ; Ladich
and Fay 2013 ). Nevertheless, holocentrids show a relationship between the distance
of the swim bladder to the inner ear and the hearing sensitivity. Members of the
subfamily Myripristinae ( Myripristis ) have an anterior swim bladder extension and
sensitivities similar to otophysines, and members of the subfamily Holocentrinae
( Holocentrus , Sargocentron ) lack a direct connection and have reduced hearing sensitivities. The size of the gas bladder and its possible effect on hearing have not been
investigated in this family.
The situation is much more complex, less straightforward, and partly contradictory within the family Sciaenidae. Ramcharitar et al. ( 2006 ) showed that two species
of western Atlantic sciaenids—the weakfi sh Cynoscion regalis and the spot
Leiostomus xanthurus —differ in swim bladder morphology and hearing sensitivity.
The swim bladder in C. regalis has a pair of anterior horns that terminate close to
the ear, while there are no extensions in L. xanthurus. Cynoscion regalis detects
frequencies up to 2 kHz, whereas L. xanthurus only up to 700 Hz. Both species do
not differ in absolute sensitivity. The low sensitivity in C. regalis is surprising (lowest threshold at 90 dB) because its peripheral hearing structures touch the swim
0.1
0.2 0.3 0.5
1 1.5 2 3
40
60
80
100
120
140
Hearing threshold (dB re 1 µPa)
Frequency (kHz)
M.k.
b
a
H.a.
S.v.
S.x.
M.a.
H.a.
S.s.
S.b.
C
Fig. 12 Comparison of hearing thresholds in four species and of the anterior swim bladder (S.b.)
and posterior cranium (C) situation in three species of the family Holocentridae (soldierfi shes). ( a )
Thresholds of Myripristis kuntee ( M.k .) and Sargocentron xantherythrum ( S.x .) are from Coombs
and Popper ( 1979 ), those of Sargocentron vexillarium ( S.v .) and of Holocentrus adscensionis ( H.a .)
from Tavolga and Wodinsky ( 1963 ). ( b ) Anatomical drawings from Hawkins ( 1986 ) based on
Nelson ( 1955 ). Upper drawing Sargocentron suborbitalis ( S.s .), lower drawing Myripristis amaena
( M.a ). Hearing thresholds from different studies need to be compared with caution because of possible differences in threshold determination between different labs (see Hawkins 1981 )
Peripheral Hearing Structures in Fishes: Diversity and Sensitivity…
have an intermediate hearing ability in terms of frequency bandwidth but not in
absolute thresholds between 0.1 and 5 kHz (Tavolga and Wodinsky 1963 ) (Fig. 12a,
b ). Surprisingly, members of the genus Sargocentron differ considerably (up to 30
dB) in sensitivity, potentially refl ecting swim bladder morphology differences (note
that only physiological but no morphological data are available for S. vexillarius
and S. xantherythrus ) or differences in threshold determination between labs (for
methodological differences see Hawkins 1981 ; Ladich and Wysocki 2009 ; Ladich
and Fay 2013 ). Nevertheless, holocentrids show a relationship between the distance
of the swim bladder to the inner ear and the hearing sensitivity. Members of the
subfamily Myripristinae ( Myripristis ) have an anterior swim bladder extension and
sensitivities similar to otophysines, and members of the subfamily Holocentrinae
( Holocentrus , Sargocentron ) lack a direct connection and have reduced hearing sensitivities. The size of the gas bladder and its possible effect on hearing have not been
investigated in this family.
The situation is much more complex, less straightforward, and partly contradictory within the family Sciaenidae. Ramcharitar et al. ( 2006 ) showed that two species
of western Atlantic sciaenids—the weakfi sh Cynoscion regalis and the spot
Leiostomus xanthurus —differ in swim bladder morphology and hearing sensitivity.
The swim bladder in C. regalis has a pair of anterior horns that terminate close to
the ear, while there are no extensions in L. xanthurus. Cynoscion regalis detects
frequencies up to 2 kHz, whereas L. xanthurus only up to 700 Hz. Both species do
not differ in absolute sensitivity. The low sensitivity in C. regalis is surprising (lowest threshold at 90 dB) because its peripheral hearing structures touch the swim
0.1
0.2 0.3 0.5
1 1.5 2 3
40
60
80
100
120
140
Hearing threshold (dB re 1 µPa)
Frequency (kHz)
M.k.
b
a
H.a.
S.v.
S.x.
M.a.
H.a.
S.s.
S.b.
C
Fig. 12 Comparison of hearing thresholds in four species and of the anterior swim bladder (S.b.)
and posterior cranium (C) situation in three species of the family Holocentridae (soldierfi shes). ( a )
Thresholds of Myripristis kuntee ( M.k .) and Sargocentron xantherythrum ( S.x .) are from Coombs
and Popper ( 1979 ), those of Sargocentron vexillarium ( S.v .) and of Holocentrus adscensionis ( H.a .)
from Tavolga and Wodinsky ( 1963 ). ( b ) Anatomical drawings from Hawkins ( 1986 ) based on
Nelson ( 1955 ). Upper drawing Sargocentron suborbitalis ( S.s .), lower drawing Myripristis amaena
( M.a ). Hearing thresholds from different studies need to be compared with caution because of possible differences in threshold determination between different labs (see Hawkins 1981 )
Peripheral Hearing Structures in Fishes: Diversity and Sensitivity…