17.6 Wednesday, Jan. 4 Cryptic and Rapid Gill Ventilation Behaviors of the Goosefish, Lophius americanus FARINA, Stacy C; Cornell University firstname.lastname@example.org
The goosefish, Lophius americanus, is a benthic sit-and-wait predator that relies on a dorso-ventrally flattened head and a slow gill ventilation rate to remain hidden from prey. The opercular chamber is characterized by long, thin branchiostegal rays and a small opening posterior to the pectoral girdle. When unperturbed, L. americanus ventilates its gills once every 60-90 seconds, in a pattern termed cryptic ventilation. After feeding or a disturbance, the ventilation rate increases to 8-45 seconds (rapid ventilation). Both behaviors are marked by a large asymmetry between the inspiration and expiration phases, although the asymmetry is much more pronounced during cryptic ventilation. The relationship between the length of inspiration and expiration phases was also explored. Previously, authors have suggested that movements of the suspensorium and opercular series play little to no role in ventilation in Lophius. High-resolution video recordings, however, confirm that such skeletal movements are actively involved in the movement of water at the beginning of the suction phase and throughout most of the pressure phase. During rapid ventilation, movements of the suspensorium and opercular series make up a large portion of the ventilation cycle. When the jaws, opercular series, and suspensorium are not driving the movement of water during the inspiration phase, the hyoid slowly depresses and the branchiostegal rays slowly expand to increase the size of the buccal and opercular chambers. This slow expansion of the chambers frequently exceeds 60 seconds during cryptic ventilation in a pattern that maintains water flow across the gills.