Thresher Shark: Habitat and Characteristics
The thresher shark is a species of cartilaginous fish with a characteristically huge tail. It’s a widely distributed animal with amazing mobility and activity, allowing it to move between the surface and deep waters quite quickly. The reproduction of these specimens is its greatest obstacle and experts consider it to be a highly vulnerable shark.
There are three species of sharks that are called “threshers”. However, in this article, we’ll only focus only on Alopias superciliosus. Read on to learn more about this huge marine specimen.
Thresher shark habitat
Thresher sharks live in tropical and temperate seas, from the surface down to 700 meters. It’s a fairly active and resistant swimmer, capable of undertaking long migratory journeys of up to 2,400 kilometers. The optimal habitat for this species is in warm waters, as that’s where the largest specimens are found.
The distinctive feature of this shark is the upper part of its tail, which is very long and striking. This caudal extension can be as large as its body and, in fact, the largest specimens reach 4.5 meters in total length.
Its body is similar to that of other sharks: cylindrical, robust, and with an elongated cone-shaped snout. In addition, it has 5 obvious fins, with a rather reduced sixth dorsal, which is located near the tail. All of them are immobile and help the shark to maintain its position in the water, except for the flow fin, which is the only one with mobility.
Their bodies maintain the typical coloration of sharks, with bluish-gray on the back, but with white colors on the belly. Although the Alopias genus contains 3 different species, it differs from the rest due to its large eyes.
Thresher shark behavior
This shark is a solitary swimmer that frequently searches for warm waters. In addition, its population is segregated by age and sex. Some experts consider this to be a strategy that improves its survival. Because of this, females, males, and the young are grouped in different places in the ocean.
According to an article in the scientific journal Marine Ecology Progress Series, this shark usually stays at depths of 200 or 500 meters during the day and close to the surface at night. This is because, thanks to its eyes, it can easily observe its prey with the help of the reflection of the sun, while at night it rises to the surface due to the lack of light.
Thresher shark feeding
Its main foods are schools of squid and fish, which is why it’s considered a specialized predator. Among the most common species in their diet are the flatback, the Humboldt squid, the lanternfish and the Pacific hake.
The tail of this shark plays an important role in its diet, as it uses it to stun and corner its prey. This is done by means of ripples that swirl in the water and stun the victim. He also uses it as a whip, hitting hard and incapacitating the target.
Thresher shark reproduction
This shark has an ovoviviparous reproduction, with a gestation period of one year and litters of two young. During their development, the offspring exhibit a behavior called ovofagia, which consists of feeding on the mother’s unfertilized eggs. To do this, they develop temporary embryonic teeth that will be lost before birth.
The offspring of the species measure between 60 and 105 centimeters at birth and mature at around 12 years of age. Furthermore, parental care is minimal since, at birth, they’re independent, but remain in a “nursery” area, where they’re protected by several females. As they grow, they migrate to new places, segregating by age.
This shark reproduces annually, but doesn’t have a defined mating season. They can copulate at any time of the year.
State of conservation
According to the International Union for Conservation of Nature, the thresher shark is listed as a vulnerable species. This is due to the fact that the specimens produce few offspring per litter and that, in addition, they’re exploited by fishing companies.
Threats of the thresher shark
The main threat that these animals have is due to selective and incidental fishing. One of the reasons for their high demand is the appreciation of their meat, fins, skin, and livers. Because of this, fishermen all over the world try to catch them.
On the Asian continent, there’s a considerable market for their fins, as they’re part of a traditional Chinese dish. However, the most sought-after parts of the specimens are their meat and liver. This is because the former is used for human consumption, while oils with a high vitamin content are extracted from the latter.
Fortunately, the International Commission for the Conservation of Atlantic Tunas and the Indian Ocean Tuna Commission have prohibited the capture of this shark. Although the efforts aren’t yet bearing fruit, several more countries have committed to cooperating in their conservation, with the aim of safeguarding marine biodiversity.It might interest you...