The Kitefin shark or Seal shark (Dalatias licha) is a species of Dogfish shark in the family Dalatiidae. It is found sporadically around the world, usually close to the sea floor at depths of 660–1,970 feet, though has been caught at a depth of 5,900 feet. It is a powerful and solitary hunter with a wide variety of prey items in its diet. It has a large liver with a lot of squalene, keeping it neutrally buoyant.
Family: Dalatiidae – Kitefin sharks
Common Name– Dogfish Sharks
Common Name– Kitefin Sharks
Status: IUCN Red List NEAR THREATENED
Average Size and Length: The typical length of the Kitefin shark is 3.3–4.6 feet. The maximum reported length has been 5.2 feet. Some research suggests Kitefin sharks reaching 5.9 feet.
Average Weight: They weigh 18 pounds on average.
Teeth and Jaw: The lips of the Kitefin shark are thick with pleats or fringes, though they are not modified to be suctorial. Its teeth are highly differentiated between the upper and lower jaws, and it has an extremely strong bite. There are 16–21 tooth rows in the upper jaw and 17–20 tooth rows in the lower jaw. The upper teeth are small, narrow and spike-shaped, curving slightly towards the corners of the mouth. The lower teeth are very large, triangular and knife-shaped, and serrated, with their bases interlocking to form a continuous cutting surface.
Head: The Kitefin shark has a short, blunt, rounded snout. The eyes and spiracles are large.
Denticles: The dermal denticles of the Kitefin shark are small and flat, with a single horizontal ridge ending in a point.
Tail: The caudal fin has a prominent upper lobe with a well-developed notch near the tip, and a barely present lower lobe.
Demographic, Distribution, Habitat, Environment and Range: The Kitefin shark can be found sporadically around the globe in tropical and warm-temperature waters, consisting of a number of widely separated populations with likely little interchange between them. In the northern Atlantic, it can be found in the Georges Bank and the northern Gulf of Mexico, and from the North Sea to Cameroon, including around the British Isles, in the western and central Mediterranean Sea, and off Madeira and the Azores. In the Indian Ocean, it is found off South Africa and Mozambique. In the Pacific, it can be found off the coast of Japan, Java, Australia and New Zealand, and the Hawaiian Islands. It is possible it can be found in other locations, and also there are some locations it hasn’t been reported at all.
The Kitefin shark is an offshore, deepwater shark. It is most common at a depth of 660–1,970 feet, but has been captured from the surface to as deep as 5,900 feet.
In one area, the Azores, the Kitefin sharks is known to segregate by sex. Females can be found commonly at a depth of 750 feet, and males between 1, 352-1,470 feet. The Kitefin shark lives the outer continental shelves and upper continental slopes, and is also found around oceanic islands and seamounts. It prefers to stay close to the sea floor. It is the only shark in its family that does stay close to the sea floor. It will venture through the water column at times.
Diet: The Kitefin shark has large teeth and a strong bite. It is a powerful and solitary predator that takes many different types of prey, like bony fishes, sharks and rays, cephalopods, crustaceans, polychaete worms, siphonophores, and possibly carrion. The occurrence of fast-swimming fishes in its diet suggests the Kitefin shark may scavenge, or have some other means of capturing faster prey. More than likely it scavenges.
The Kitefin shark also takes bites out of animals larger than itself, like the Cookiecutter shark.
The Kitefin shark is preyed upon by larger fishes and sharks, and even Sperm whales.
Aesthetic Identification: The Kitefin shark has a somewhat slender, elongated body. Its coloration is a uniform dark brown or gray, sometimes with faint black spots on the back. The fins have white or translucent trailing edges. The tip of the caudal fin is black. There have been cases of a partial albino Kitefin sharks documented, which interestingly, didn’t inhibit its ability to hunt and capture prey.
The first dorsal fin is slightly smaller and shorter-based than the second, and neither has spines. The first dorsal fin originates behind the free rear tip of the pectoral fins, while the second originates above the middle of the pelvic fin bases. The pectoral fins are short and rounded.
Biology and Reproduction: The Kitefin shark has a very large oil-filled liver that keeps it neutrally buoyant.
In some locations, males are known to outnumber females. In the Gulf of Genoa, the ratio is 2:1 and at times even 5:1.
Parasite data on the Kitefin shark is limited. Though, an examination of two sharks caught off Ireland found three nematodes in the stomach lumen.
The Kitefin shark is ovoviviparous. Research suggests that breeding occurs throughout the year, however only a few populations have been documented and it is poorly known. In the Mediterranean, this is confirming with peaks in spring and fall. Females breed every other year. The litter size is 10–16, increasing with female size. The pups are born at a length of 12–18 inches, varying by geographic location, after a possible gestation period of two years. The males mature sexually at a length of 2.53–3.97 feet, and the females at a length of 3.84–5.22 feet.
Behavioral Traits, Sensing and Intelligence: The Kitefin shark is a powerful predator, and it hunts solitary. It is known to take bites out of larger organisms. At times, it has been documented to form large groups.
Speed: Because of its large squalene-filled liver, the Kitefin shark cruises slowly through the water while expending little energy.
Kitefin Shark Future and Conservation: The Kitefin shark is fished commercially for its meat, skin, and liver oil, primarily by Portugal and Japan. They are caught as bycatch, bottom trawling and hook-and-line. The skin is made into a type of shagreen useful in the making of furniture and jewelry, and is also favored for the manufacture of “boroso”, a Spanish polished leather. In the Medeterranean, they are caught in gillnets often. They have declined significantly over the years, exploited significantly. In the Azores they were targeted and depleted by more than 50% in the Atlantic between the 1970’s and 1990’s. That particular fishery is shut down today. The low reproductive rate of this species renders it susceptible to overfishing and, coupled with known population declines, has led it to be assessed as Near Threatened.
Its upper teeth have been found lodged in underwater fiberoptic cables.
Kitefin Shark Recorded Attacks on Humans: Not a threat to humans.