Pacific sailfish: Fastest fish in the ocean amazes scientists

It can reach up to three metres in length, weigh dozens of kilograms, and embarrass even the fastest "sprinters" living on land with its speed. 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 such 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. The bluefin tuna accompany it - 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 do we measure the speed at which the Pacific sailfish moves? 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 us to estimate its speed.