Meeting Abstract
Flatfishes are benthic fishes with laterally flattened bodies and two eyes on one side of the head. While their neurocranium is asymmetrical to accommodate their unique eye position, much of the rest of the cranial skeleton is symmetrical, including the opercular bones and branchiostegals that make up the gill chamber. Our study examines whether the kinematics and pressures generated by these chambers are also symmetrical. We performed a two-part experiment on Isopsetta isolepsis using surgically implanted sonomicrometry crystals on the eyed and blind side operculum, epaxial and urohyal to measure the positions of the bones during ventilation, and pressure transducers on the eyed and blind side operculum to track the pressures produced before and after burial. We found that flatfishes can perform both symmetrical and asymmetrical breathing, both in terms of kinematics and pressures, above and below the sediment. Asymmetry, when present, was very large in magnitude, with flatfishes “favoring” either the blind or eyed side, depending on how their head was positioned. We also found that Isopsetta have the ability to shift from asymmetrical movement during burial and symmetrical movement during ventilation and vice versa whether they were resting, swimming above, or buried beneath the sediment. Furthermore, from analyzing this behavior, we were able to conclude that the flatfish were using the urohyal as a shunt to pass water from the eyed to the blind side of the head to fluidize sand underneath the head during burial.
