Basking Shark Breaching

Breaching Basking Shark © Anthony Robson.Basking Sharks seem so slow and cumbersome that many people don’t believe they can breach clear of the water. Some earlier researchers concluded that the reports they had received from fishermen and shark hunters were in error – how wrong can you be!

Basking Sharks seem to breach most commonly when in large groups, and when consistent courtship activity is taking place. This suggests that breaching may serve as some form of social or sexual function, as with the White Shark, perhaps as a method for demonstrating fitness or receptiveness to mating. 

It has also been suggested in the past that Basking Sharks breach to dislodge external parasites (such as the parasitic lamprey Petromyzon marinus), but this seems to be a remarkable expenditure of energy for such a small reward, so there must be more to it than that.

Basking Sharks ordinarily cruise at around 2.5 to 4mph however in order to breach completely out of the water, they must be capable of reaching much greater speeds. Breaching occurs without warning, and is hardly graceful – the shark erupts from the water, often rolling in mid-air before crashing back in to the water. Sometimes a shark will breach three or more times every thirty seconds, while other sharks carry on swimming nearby in an unconcerned manner.

For this reason it makes sense for any observer on a boat to move away as quickly as possible when sharks start to breach in their vicinity. The only known fatalities involving the Basking Shark occurred in the Firth of Clyde before World War II, when a breaching shark hit a small boat at the surface, capsizing it and drowning three of the occupants – you have been warned!