A. Body Shape:
Swimming is essential for buoyancy and that is why sharks have a fusiform body(round and tapering at both ends). This shpae reduces drag and minimises swimming effort.
B. Caudal Fins (Tail fin):
The shark’s lower lobe is smaller than the sharks upper lobe and thus when swimming if propels the shark downwards and forwards.
C. Pectoral Fins:
The main function of the pectoral fin is to provide lift to counteract the caudal fin’s downward motion. These fins are rigid and results in a horizontal passage through the water.
D. Horizontal Keel:
The horizontal keel (thickened ridge on top of the caudal fin) is an adaptation for fast swimming because it reduces turbulence.
As a shark or batoid swims, scales create a series of vortices or whirlpools behind each scale. This enables a shark to swim efficiently.
F. Swimming Speed:
Generally sharks swim at speeds less than 5 kph but some sharks such as Makos can reach a speed of 48 kph. Bottom sharks are usually slow swimming.