The salmon shark – the unknown cousins of the Great White:

At the end of July, thousands of salmon sharks gather in the estuaries of Alaska, in particular in Prince William Sound, and wait for the return of their favourite lunch, the Pacific salmon. Every year, their numbers increase. This is partly because of the considerable changes in the climate and resulting increased water temperatures but, on the other hand, it is linked to the increasing numbers of salmon, partly because the stocks are being boosted by fish-breeding farms. Dr. Barbara Block of the Hopkins Marine Station at Stanford University has, in recent years, attached satellite transmitters to around 500 salmon sharks to enable her to monitor the extent of their habitat and their migration routes. These transmitters are Smart Position Only Tags, in other words, they are attached to the dorsal fin and, every time the animal surfaces, its exact position is transmitted to the satellite. These signals can be tracked via the internet...

The females withdraw to desert regions of the oceans to give birth. Places where there is little food do not attract predators – making these regions safe nurseries. The nomads of the seas cover 3000 kilometres or more twice a year. One subject even managed 10,000 kilometres to Hawaii. Temperatures may reach and even exceed 20 degrees here! The fact that these animals can compensate for such temperature changes is nothing short of sensational. Change of scene: Richard Peirce, British adventurer and shark conservationist from Cornwall leads diving expeditions every summer to the Atlantic salmon shark, or porbeagles, off the west coast of the British Isles. For some years, he has been observing the development of the porbeagle population.