Contraction of the dorsal muscle Rocker bone Articulation of the 1st neural spine + epineural on the 1st vertebra Ligament Left lateral views of the sound producing
mechanism in males Ophidion rochei.
PRELIMINARY RESULTS ON THE SOUND PRODUCTION IN OPHIDION
ROCHEI
Eric Parmentier1, Branko Dragicevic2, Yves-Eric Corbisier1, Grégory Bouillac1, Jakov Dulčić2 1Laboratoire de Morphologie Fonctionnelle et Evolutive, Université de Liège, Liège, Belgium
2Institute of Oceanography and Fisheries, POB 500, 21000 Split, Croatia
Contraction of the ventral muscle 0 20 40 60 80 100 120 140 1810 2010 2210 0010 0210 0410 0610 # s o u n d s/ 1 0 m in u te s Time s u n s e t s u n ri s e
Ophidion rochei. Number of calls per 10 minutes at
three different sites. Specimens of Cusk-eels Ophidion rochei were
recorded for the first time.
Passive acoustic detection highlight their nocturnal activities. 0.5 1.0 1.5 2.0 200 400 600 800 Time (sec) F re q eu n cy ( Hz )
Spectrogram of the train pulse in Ophidion rochei.
Fundamental frequency 2nd Harmonic
Sounds last between 1 and 3 sec, and consist of trains of 19 to 35 pulses having an average length of 26ms. The sonogram of the chatter recording consisted of a series of frequency pulses of 180-200 Hz with at least one harmonic.
40 60 80 100 120 140 1 6 11 16 21 26 31
In each train, the pulse period and intensity raise to reach a cruising speed in which the pulses are grouped in pairs.
Sounds should be
produced by the
vibration of the three membranes in response
to the alternate
contraction of dorsal and ventral sonic muscles. The contraction of the dorsal muscle originates the first neural arch + epineural to pivot rostrally around its articulations on the first vertebral body, and the counter-clockwise rotation of the rocker bone, pushing the membranes backward.
The contraction of the ventral muscle originates the clockwise rotation of the rocker bone, pulling
the SWB membranes
forward.
Periods of the different pulses in a given call in Ophidion
rochei P eri o d (m s) Dorsal muscle Ventral muscle Rocker bone Ligament Rocker bone Swimbladder Ligament 1st Vertebra 1st Epineural rib 1st Neural spine 4th vertebra
The sound producing
mechanism in O. rochei implies mainly the first vertebra, the rocker bone, sonic muscles originating on the head and the swim bladder specializations with the presence of an inner cone (megaphone ?) and three membranes.
membranes
Note : the sagittal section of the swimbladder is in diagrammatic view
1st Epineural rib
Schematic of the main part of the sound-producing apparatus in Ophidion rochei
