Structure, function, and neural control of pectoral fins in fishes

Fin-based propulsion systems perform well for both high-speed cruising and high maneuverability in fishes, making them good models for propulsors of autonomous underwater vehicles. Labriform locomotion in fishes is actuated by oscillation of the paired pectoral fins. Here, we present recent research on fin structure, fin motion, and neural control in fishes to outline important future directions for this field and to assist engineers in attempting biomimicry of maneuverable fin-based locomotion in shallow surge zones. Three areas of structure and function are discussed in this review: 1) the anatomical structure of the fin blade, skeleton, and muscles that drive fin motion; 2) the rowing and flapping motions that fins undergo for propulsion in fishes; and 3) the neuroanatomy, neural circuitry, and electrical muscle activity that are characteristic of pectoral fins. Research on fin biomechanics, muscle physiology and neural control is important to the comparative biology of locomotion in fishes and application of fin function for aid in aquatic vehicle design. Recommendations are made regarding fin propulsor designs based on the fin shape, activation pattern, and motion. Research on neural control of fins is a key piece in the puzzle for a complete understanding of comparative fin function and may provide important principles for engineers designing control systems for fin-like propulsors.