278
displacements, and that is a relatively short range sensory system (one to two body
lengths) (Coombs and Janssen 1990 ). Nocturnal studies determined that juvenile
toadfi sh only attacked prey within approximately one half of toadfi sh body length
(Price and Mensinger 1999 ), however it was uncertain if this was the range at which
the prey were detected or w hen the attack commenced. Subsequent studies, using
the telemetry tag, with large (30 cm sl) adult toadfi sh, indicated that small baitfi sh
were only detectable by the lateral line at approximately 10 cm or a 1/3 of a body
length suggesting that, at least in toadfi sh, the lateral line mediates predator prey
interactions at relatively short distances (Palmer et al. 2005 ) (Fig. 3 ).
3.2 The Utricle
The otolithic endorgans in teleost fi shes (saccule, utricle, and lagena) have dual
vestibular and auditory roles and function to encode linear particle motion. The saccule is the largest otolith and considered the primary auditory endorgan in most fi sh
species (Popper and Fay 1993 ). The response characteristics of saccular afferents
have been studied across a wide variety of fi shes including goldfi sh (Fay 1978 ),
midshipman (Sisneros and Bass 2005 ), sleeper goby (Lu et al. 1998 ), and toadfi sh
(Fay and EddsWalton 1997 ), and are sensitive to linear acceleration and directionally sensitive to acoustic particle motion functioning predominantly as a low frequency detector (60–1000 Hz). The toadfi sh saccule is well adapted to detect the
fundamental frequency of the male boatwhistle sound (~150 to 200 Hz) and grunt
vocalizations (~50 to 250 Hz) (Edds-Walton et al. 1999 , 2002 ; Maruska and
Mensinger 2009 ).
Unlike its congener Poricththys , the saccular nerve in Opsanus sp. was diffi cult
to access, thin and variably branched and not amenable to implants. In contrast, the
utricular nerve was easily accessible and of suffi cient size for microwire insertion.
The smaller utricular otolith has received less attention than the saccule and there is
limited information on its physiology, having been examined in only a few species
of fi shes. Its vestibular role as a linear accelerometer had been established in normal
(Rabbitt et al. 1995 ) and post space fl ight toadfi sh (Boyle et al. 2001 ). Utricular
afferents also were determined to be sound sensitive and showed directional
responses to 140 Hz in the goldfi sh (Fay 1984 ) and 50–400 Hz in the sleeper goby
Dormitater latifrons (Lu et al. 2004 ). Therefore, the utricle provided a good candidate to investigate multimodal sensory input.
Wild and captive toadfi sh normally spend long periods of time motionless inside
sheltered habitats with occasional brief forays limited mainly to foraging. Pre- and
post-operative fi sh displayed similar behavior, and the tag or tether did not restrict
movement, inhibit respiration or precipitate behavior to dislodge the devices.
Recording fi delity was similar between direct recording nerve recording and using
the telemetry tag or tether. The toadfi sh showed full recovery from the anesthesia
within 2 h and resumed feeding within 24 h indicating that the fi sh quickly recovered and was displaying normal behavior during the testing.
A.F. Mensinger
displacements, and that is a relatively short range sensory system (one to two body
lengths) (Coombs and Janssen 1990 ). Nocturnal studies determined that juvenile
toadfi sh only attacked prey within approximately one half of toadfi sh body length
(Price and Mensinger 1999 ), however it was uncertain if this was the range at which
the prey were detected or w hen the attack commenced. Subsequent studies, using
the telemetry tag, with large (30 cm sl) adult toadfi sh, indicated that small baitfi sh
were only detectable by the lateral line at approximately 10 cm or a 1/3 of a body
length suggesting that, at least in toadfi sh, the lateral line mediates predator prey
interactions at relatively short distances (Palmer et al. 2005 ) (Fig. 3 ).
3.2 The Utricle
The otolithic endorgans in teleost fi shes (saccule, utricle, and lagena) have dual
vestibular and auditory roles and function to encode linear particle motion. The saccule is the largest otolith and considered the primary auditory endorgan in most fi sh
species (Popper and Fay 1993 ). The response characteristics of saccular afferents
have been studied across a wide variety of fi shes including goldfi sh (Fay 1978 ),
midshipman (Sisneros and Bass 2005 ), sleeper goby (Lu et al. 1998 ), and toadfi sh
(Fay and EddsWalton 1997 ), and are sensitive to linear acceleration and directionally sensitive to acoustic particle motion functioning predominantly as a low frequency detector (60–1000 Hz). The toadfi sh saccule is well adapted to detect the
fundamental frequency of the male boatwhistle sound (~150 to 200 Hz) and grunt
vocalizations (~50 to 250 Hz) (Edds-Walton et al. 1999 , 2002 ; Maruska and
Mensinger 2009 ).
Unlike its congener Poricththys , the saccular nerve in Opsanus sp. was diffi cult
to access, thin and variably branched and not amenable to implants. In contrast, the
utricular nerve was easily accessible and of suffi cient size for microwire insertion.
The smaller utricular otolith has received less attention than the saccule and there is
limited information on its physiology, having been examined in only a few species
of fi shes. Its vestibular role as a linear accelerometer had been established in normal
(Rabbitt et al. 1995 ) and post space fl ight toadfi sh (Boyle et al. 2001 ). Utricular
afferents also were determined to be sound sensitive and showed directional
responses to 140 Hz in the goldfi sh (Fay 1984 ) and 50–400 Hz in the sleeper goby
Dormitater latifrons (Lu et al. 2004 ). Therefore, the utricle provided a good candidate to investigate multimodal sensory input.
Wild and captive toadfi sh normally spend long periods of time motionless inside
sheltered habitats with occasional brief forays limited mainly to foraging. Pre- and
post-operative fi sh displayed similar behavior, and the tag or tether did not restrict
movement, inhibit respiration or precipitate behavior to dislodge the devices.
Recording fi delity was similar between direct recording nerve recording and using
the telemetry tag or tether. The toadfi sh showed full recovery from the anesthesia
within 2 h and resumed feeding within 24 h indicating that the fi sh quickly recovered and was displaying normal behavior during the testing.
A.F. Mensinger