Meeting Abstract
Gill ventilation is the process by which fishes pump water over the gills by cyclically expanding and compressing the buccal and gill chambers. While these chambers are generally modeled as operating independently of one another, they are mechanically linked, and these linkages play an underappreciated role in ventilatory mechanics. Our goal was to quantify the extent to which mechanical linkages between the buccal and gill chambers influence ventilatory kinematics. To accomplish this, we analyzed XROMM (X-ray Reconstruction of Moving Morphology) animations of catfish ventilatory sequences to calculate (1) the contribution of the suspensorium to opercular expansion and (2) the contribution of the operculum to jaw depression. We found that abduction of the suspensorium contributes 10-30% to abduction of the operculum. Therefore, as the suspensorium abducts and expands the mouth chamber, it is also contributing simultaneously to gill chamber expansion, as opposed to these chambers operating independently. Movements of the opercular bones may also slightly contribute to mouth chamber expansion, which is another way in which these chambers are linked. Our study provides a new framework for the understanding of gill ventilation in terms of mechanical linkages instead of pumping of separate chambers.
