Meeting Abstract
Chaunacidae (sea toads and coffinfishes) is a family of anglerfishes (Lophiiformes) specialized for living on the floor of continental slopes at depths of up to 2,500 meters. Like many other Lophiiformes, they are globose sit-and-wait predators. Chaunacids breathe extremely slowly, similarly to some shallow-water anglerfishes (Lophiidae). Lophiids can take up to five minutes to complete a single ventilatory cycle, but the ventilatory rates of chaunacids are unknown. We described the morphology of the chaunacid gill chamber with dissection and micro-CT of preserved Chaunax suttkusi. We also analyzed the ventilation of several species from ROV videos by the NOAA Okeanos Explorer. We found that the large gill chambers of chaunacids are lined with thin layers of muscle tissue that extend posteriorly from the branchiostegal musculature to the gill opening, which is positioned behind the pectoral girdle, in the last third of the length of the body. From our video analysis with MATLAB, we determined that chaunacids can hold approximately 27.7% of their body volume in their gill chambers, which can be exhaled in under 6.6 seconds. Unlike in lophiids, who are continuously expanding their gill chambers, chaunacids may be able to hold their gill chamber at maximum expansion for long periods of time. This specialized gill chamber and ventilatory behavior likely assists in the chaunacid life strategy of expending little energy and waiting to ambush prey.
