Thresher Shark

The Thresher Shark is one of the most visually stunning sharks in the Mediterranean. It is easily identified by its exceptionally long tail, which resembles a scythe and often accounts for half of the total length of the animal. The body is robust and torpedo-shaped with a short snout and large pectoral fins. The dorsal colouration is typically a metallic grey or leaden hue, while the underside is stark white.

Two species live in the Mediterranean. The Common Thresher (Alopias vulpinus) is the most frequent and is known for its large size and grey colour. The Bigeye Thresher (Alopias superciliosus) is recognisable by its huge eyes, which reach the top of its head and let it see in the dim light of deep waters. The Pelagic Thresher (Alopias pelagicus) lives in the Indian and Pacific Oceans and has not been recorded in the Mediterranean.

This is a fish of the open sea. It lives and moves in the open ocean from the surface down to depths of 500 metres. In the Mediterranean, it generally stays away from the coast in deep waters, although it occasionally approaches land while following schools of prey fish.

The shark is an intelligent hunter. It feeds primarily on schooling fish such as sardines, anchovies, and mackerel, as well as squid. Its hunting technique is unique among fish, as it approaches a school and uses its long tail like a whip. With a powerful and rapid strike, it stuns or kills multiple fish at once before consuming them at its leisure.

The female gives birth to young that have already hatched inside the mother's body. A remarkable aspect of their development is that the unborn pups feed on unfertilised eggs in the womb. Gestation lasts 9 months, and the female gives birth to a small number of pups, usually 2 to 4. However, these newborns are giants because they are born measuring over one metre.

It is usually caught in the open sea by professional vessels targeting tuna and swordfish using either surface longlines or nets. While the meat is edible, the fins are the most sought-after part of the fish. Due to its relative rarity, it is not a primary commercial target in many regions.

Scientists have discovered that the Thresher Shark is an endothermic fish similar to the Great White Shark. This means it can maintain its body, eyes, and brain at a higher temperature than the surrounding water. This provides the shark with immense energy and speed during hunts. Unfortunately, research indicates that the Mediterranean population has declined dramatically, and it is currently classified as an Endangered species in the region. This status is primarily due to the shark giving birth to very few young and being unable to easily replace losses caused by fishing.