Meeting Abstract

P1.60  Sunday, Jan. 4  Coordination of Muscle Activity between Ventilation and Feeding in Spiny Dogfish SCOTT, A.J.*; GERRY, S.P.; RAMSAY, J.; WILGA, C.D.; University of Rhode Island; Arcadia University; University of Rhode Island lilang098@hotmail.com

Elasmobranchs (sharks, skates and rays) as well as other aquatic organisms are believed to use similar mechanisms during ventilation and feeding. These two behaviors rely on coordinated movements of the mandibular, hyoid and branchial arches. Yet it is not known whether sharks suspend or alter ventilation when capturing or processing prey. The coordination of muscle activity during ventilation and feeding was investigated in spiny dogfish, Squalus acanthias. Electromyograms were recorded from thirteen mandibular, hyoid and branchial muscles thought to mediate ventilation and/or feeding. Muscle activity was compared between resting, swimming, prey capture and processing behaviors. While at rest and swimming, the branchial adductor and several constrictor muscles are active in a constant cyclic pattern as expected in a suction ventilator. These muscles are also active during feeding, however, the duration of activation differs and was variable among feeding events. Prey capture and processing are characterized by additional activation of hypobranchial and jaw adductor muscles. Previous studies have shown that feeding and ventilation places different functional and environmental constraints on a swimming versus feeding fish because the same structures are used for both behaviors. However, this research shows that spiny dogfish adjust which muscles are active as well as activation pattern of these muscles dependent on behavior. Since jaws are thought to have evolved initially to enhance ventilation, muscle activity during feeding can be thought of as an exaggeration of ventilation or forced ventilation. Further investigation will show if sharks with other ventilatory modes follow a similar pattern of coordination.