Swordfish and sharks are predators that often inhabit the same environments. However, it was believed that normally swordfish tended to avoid conflict with sharks. It turns out that in some regions of the Mediterranean Sea, swordfish are attacking and killing sharks.
In April 2020 a female shark of the genus Alopias sp. was found dead on the beaches of Lebanon. However, the strange part is that the shark had only one bruise: the tip of a swordfish beak embedded in the back of its head. This was not the only case of its kind. Several sharks, especially in this region, have been found dead in the same situations.
These swordfish attacks may be the first indications of what were, until recently, just fishermen's stories. These animals are probably using their beaks in high-speed attacks. There are indications, moreover, that the fish responsible for attacking the female Allopsias in Lebanon was a young animal, measuring around 3.5 metres.
A fish with a sword, literally
As much as it may not seem like it, swordfish can be giant animals, reaching up to 4.5 meters. These fish usually hunt squid and fish such as tuna. However, these predators can have violent behavior and attacks on whales, turtles and even boats have been recorded. It is believed, however, that swordfish can mistake other animals for their prey and therefore,they end up attacking.
The cases of sharks being attacked, however, are more numerous. Moreover, most beak wounds are in vital regions of the shark, such as the head or gills. It is believed that there may be a complex reason for these attacks, and there are two possibilities.
Sharks' gills and heads are very sensitive, so these areas are targets for marlin. Image: Christel SAGNIEZ/Pixabay
Why are swordfish attacking sharks?
Swordsmen may be attacking to defend themselves or to eliminate competitors.
The answer has to do with ecology. As stated earlier, sharks and swordfish live in the same environments and often have the same prey. Therefore, when there is enough prey for swordfish and sharks, the environment tends to be stable. However, the Mediterranean Sea is the basis of the fishing economy of much of Europe, Asia and Africa. Therefore, the fishing industry has exploitedintensely these waters.
The fishing industry has a strong impact on the Mediterranean Sea. Image: Free-Photos/Pixabay
With too much fishing there are fewer fish in the water. There's no time for reproduction to occur and the number of animals drops dramatically. So maybe that's why the marlin are attacking the sharks - to eliminate competitors for food. This is a behavior seen in other species, but it's getting more and more intense with marlin.
There is also the possibility that the marlin are doing this to defend themselves. With prey numbers dwindling, the sharks may be hunting young marlin, in which case the only alternative is to attack the predator to save themselves. It is no coincidence that most of the sharks involved are of the species Prionace glauca e Isurus oxyrinchus These species are opportunistic and feed on small fish. Also, they attack nothing less than young swordfish, like the one that attacked the female shark found in Lebanon.