Astonishing speeds: The Pacific sailfish, ocean's fastest marvel

It speeds through the depths of the oceans at an astonishing rate of over 120 km/h. If it were "swimming" in a residential area, it would optimistically receive a hefty fine and several demerit points. This fish amazes scientists from around the world.

It can reach up to three metres in length, weigh dozens of pounds, and with its speed, embarrasses even the fastest "sprinters" living on land. A cheetah can accelerate to 110 km/h, while the Pacific sailfish has no problem temporarily reaching even 130 km/h in the ocean. This astonishing fish has fascinated the scientific community for a long time.

What exactly makes the Pacific sailfish traverse the ocean depths at incredible speeds? Its entire body is powered by a powerful caudal fin, which, combined with a streamlined shape, makes the Pacific sailfish a living underwater rocket. What role does its characteristic dorsal fin play then?

The sailfish owes its name to its dorsal fin, which resembles a sail. The fish can retract it while accelerating, but the dorsal fin is crucial during hunting. Raising the "sails" increases its manoeuvrability, resembling top-notch underwater acrobatics. A fish manoeuvring in this way stuns smaller prey with its rostrum, a beak-shaped structure.

The Pacific sailfish is even listed in the Guinness Book of Records as the fastest fish species in the world. It is accompanied by the bluefin tuna—it is not entirely clear which of these fish deserves the title of the fastest.

"Two species are frequently cited as prime contenders to be the fastest fish, although it is notoriously difficult to obtain accurate measurements under natural conditions," informs the Guinness Book of Records.

How, then, can the speed at which the Pacific sailfish moves be measured? One method is to calculate the speed based on the length of the fishing line pulled out. The number of metres of line the sailfish pulls out in a given time allows for estimating the speed at which it moves.