Knifefish turning performance during forward swimming

Rapid turning and swimming contribute to ecologically important behaviors in fishes such as predator avoidance, prey capture, mating, and the navigation of complex environments. For riverine species, such as knifefishes, that are commonly challenged by turbulent flows, turning control may be effective for counteracting adverse locomotive perturbations. Most research on fish maneuvering focuses on fish with traditional fin and body morphologies, which primarily use body bending and the pectoral fins during turning. However, it is uncertain how fishes with uncommon morphologies, are able to achieve sudden and controllable turns. Here we studied the turning performance and the turning hydrodynamics of the Black ghost knifefish (Apteronotus albifrons, N=6) which has an atypical elongated ribbon fin. Fish were filmed while swimming forward at ~2 BL s-1 and feeding from a fixed feeder (control) and an oscillating feeder (75 Hz) at two different amplitudes. 3D kinematic analysis of the body re...