Mackerel are active fish, spending their lives swimming, and they have developed a body shape for this purpose. Their body tapers at both ends, meaning they can swim through the water easily, with their curved rear ensuring there is little drag to slow them down. The scales on the body are very small, lessening water resistance. Even the bones of their jaws are arranged so as not to disrupt their streamlined profile. And their eyes are set deep within their sockets, rather than protruding. The two dorsal (back) fins along the back are small, and there are special grooves that allow these to be folded down when the
mackerel is swimming quickly, which reduces drag. The part of the body connecting to the caudal (tail) fin, called the caudal peduncle, is narrow. The tail itself is tall, narrow, and rigid.This design is ideal for long-distance, highspeed
