Meeting Abstract
82.3 Monday, Jan. 6 11:00 Coordination of Ventilation and Feeding in Elasmobranchs WILGA, C*; DUQUETTE, D; FICARRA, L; Univ. of Rhode Island; Univ. of Rhode Island; Univ. of Rhode Island cwilga@uri.edu
Ventilation behavior must function independently of and cooperatively with other behaviors that are critical to the life history of the fish, such as swimming, feeding, and mating. The coordination of ventilation with feeding is investigated in three species of suction ventilating elasmobranchs to determine how the transition to feeding from ventilation occurs. Cranial morphology influences the ventilatory mechanism, and determines what prey can be captured and ingested. Three elasmobranch species (spiny dogfish, bamboo shark, and skate) are compared to evaluate the influence of torpedo vs flattened shaped heads, subterminal vs ventral mouth location, and epipelagic vs benthic species. Cranial movements and pressure generation were measured to determine how the ventilation mechanism is altered to capture prey. Sonomicrometry and pressure recordings of the oral, hyoid, and pharyngeal cavities during normal ventilation, prey capture, and the gape cycle prior to the capture event are compared. Suction feeding appears to be amplification of the suction ventilation mechanism with a shorter duration. Ventilatory gape cycles are longer than that of captures with smaller pressure changes. Hyoid and pharyngeal depression are the primary means of volumetric change during ventilation, in contrast to captures where changes in width also contribute to total volumetric change. Pharyngeal cavity changes also comprise a larger percentage of total volumetric change during feeding compared to ventilation, presumably to move the prey as well as the larger volume of water. Head shape, mouth position, and habitat differences among the species indicate that the elasmobranch ventilation mechanism is flexible. Whether the gape cycle prior to the capture event is an interrupted ventilatory cycle or a preparatory feeding phase is discussed.
