Let’s talk about the Thresher Shark…

 

I was told a story by one of our happy guests that joined us on a Shark Cage Dive, of an incident that occurred off some coast in the US, of a thresher shark, a story I will now pass onto you.

A fisherman was hand lining tuna. (This means that a fishing rod was not used, but rather just the fishing gut, a lure and some serious fisherman, using speed and strength, with little regard of the damage this could inflict upon their hands. This is the chosen fishing method employed by most snoek fisherman in South Africa, they say they are afforded a greater sensitivity to the catch when not separated by a rod.) So back to the story; these fishermen were out in the ocean, hand lining tuna, when one of the gents got a solid bite, and started pulling in his catch. They noticed a fin break the surface as it chased after their catch, and so our illustrious fisherman, pulled faster, and harder, and fought to keep the tuna. As the tuna got closer to the boat, so did the shark, and with a final burst of strength, the fisherman pulled the tuna, right over the boat! That’s right, he had pulled too hard, so that the momentum had caused the fish to fly right over their heads and land in the water on the other side of the boat. Well this would have been alright; if only the shark that was in hot pursuit, had not attempted to follow the tuna, and breached itself right into the boat! Apparently, the thresher, thrashed about and the guys who at this point had apparently decided not to play along, abandoned ship, well boat, and swan back to shore!

Now we have all heard “fishing stories” but I am inclined to believe this one, have you ever seen a thresher shark fly? In light of this, I think I may be inclined to believe the story, how about you?

Let’s move onto some facts we know about these amazing sharks and not just fisherman’s tales.

With their doe eyed and unassuming faces, these sharks pose very little threat to humans, the largest threat is of a diver being hit by their enormous tails, actual attacks on humans by thresher shark, are practically unheard of! After all, our fishing story showed very clearly that the shark was after the tuna and not the fishermen!

These poor sharks are hunted as a sport, as well as for their fins, liver and oil, and have almost been fished into extinction, to the point that laws have been past to protect the species, especially as they have such a low reproductive rate, lower than that of other sharks!

Today, there are three known species of the Thresher Shark;

The Pelagic Thresher, the Bigeye Thresher and the Common Thresher.

 

Though it is believed that there is a fourth, this cannot as yet be confirmed.

The most distinctive feature about these sharks is their tails, or their caudal fin. This is very often and in most cases the same size as the shark’s body, with the largest known thresher sharks reaching lengths of more than 6 meters, that’s like 20 plus foot, and weighing in at about 600kg. The Bigeye Thresher is the largest of the species, with the Pelagic Thresher coming in as the smaller. They grow slowly, and don’t live much beyond 22 years, reaching maturity only between 8 and 13 years!

Thresher’s sharks are still clouded in some mystery, though it is known that they prefer the Pacific and Indian Oceans and don’t much like very deep water, hanging about in waters of no more than 500 meters, off the coasts of America and Asia.

A further very cool and unique addition to this beautiful shark is that they have special thermoregulation, meaning that they produce internal heat, by enhancing their metabolism and muscle shivering.

The Thrasher shark is a loner, but sometimes, and only in the Indian Ocean, they would gather in large groups, the reason for this, is still unknown!

As already alluded to earlier, these sharks preferred meal choice is tuna, mackerels and sometimes certain sea birds. They love to hunt schools of fish, and use their tails as a weapon, often killing their quarry with one whip of their massive tails! As we heard earlier, they also fly! Well you know what I mean.

As with all our beautiful marine life, and specifically our sharks, the biggest threat to these magnificent creatures is…you guessed it, humans! We hunt them for sport, their livers and fins as well as them falling prey to bycatching! When will we learn to live in harmony?

Till we meet again, keep that toothy grin!

friendly shark

By Nadine Bentley