The Strait of Gibraltar is one of the busiest waterways in the world for these sea predators. In this sea, one of the most extraordinary migration odysseys on the planet is taking place.
Early spring: giant schools of Atlantic bluefin tuna from the Atlantic Ocean swim towards and through this bottleneck to deposit their genetic heritage in the gentle, warm currents of the Mediterranean.
Some specimens can reach well over 500 kilos, having spent all winter devouring huge quantities of herring, anchovies, mackerel and sardines.
But now, it is not hunger that motivates them, but something even more powerful the instinct of perpetuation, driving them onward, despite the dangers.
Because waiting for these huge fish is their mortal enemy, the only predator that can compete with them in speed, strength and intelligence. Killer whales.