The kitefin shark/seal shark, (Barría, et al., 2018; Bester and Burgess, 2022; Mallefet, et al., 2021; Chatzispyrou, et al., 2019; ERGÜDEN, et al., 2017; Kabasakal and Kabasakal, 2002; "Kitefin Shark", 2022; Kousteni, 2021; Mulas, et al., 2021; Piscitelli and De Maddalena, 2005; Santoro, et al., 2021), has a wide but largely fragmented range. In the western Atlantic Ocean, it can be found in the Georges Bank (between Cape Cod, Massachusetts and Nova Scotia, Canada), eastern Florida, and the Northern Gulf of Mexico. In the eastern Atlantic Ocean, it ranges from the North Sea to Cameroon as well as around the Canary Islands. In the western Indian Ocean, it is found from Mozambique to South Africa. In the Pacific Ocean, it lives in the waters around Japan, Australia, New Zealand, and Hawaii. The kitefin shark also lives in the Mediterranean Sea, found mostly in the western and central basin, and rarely in the eastern basin. Few specimens have also been spotted in the Ionian Sea (between Italy and Greece), the Aegean Sea (between Greece and Turkey), the Marmara Sea (connects the Black Sea to the Aegean Sea), and the Black Sea.
The kitefin shark is a rare deep-sea shark, inhabiting insular and outer continental shelves in warm temperate, and tropical waters. It is most commonly found in the mesopelagic to benthic zones of the ocean. It can be found at depths of 37 to 1800 meters but is most commonly found at 200 to 600 meters. (Barría, et al., 2018; Bester and Burgess, 2022; ERGÜDEN, et al., 2017; Kabasakal and Kabasakal, 2002; "Kitefin Shark", 2022; Kousteni, 2021; Navarro, et al., 2014; Santoro, et al., 2021)
The kitefin shark is moderately sized with an average length of 1.0-1.4 meters with a maximum recorded length of 1.82 meters. Adult males generally range from 0.77-1.21 meters (average of 1 meter) while adult females are, on average, slightly larger, ranging from 1.17-1.59 meters (average of 1.2 meters). At birth they are 30-40 centimeters in length.
They have short, blunt, conical snouts, arched mouths, thick lips, and large eyes that help them perceive small amounts of light in the deep ocean. Inside their mouths, their teeth are asymmetrical, curving slightly inward. The upper and lower jaws have 19 teeth each. The upper teeth are narrow and smooth while the lower teeth are large, broad, triangular, and serrated with overlapping bases. They have five gill openings that are short and moderately broad. Their fins are small and rounded in shape. The first dorsal fin begins behind the tips of the pectoral fins and is closer to the pectoral fins than the pelvic fins. The second dorsal fin is slightly larger than the first and starts around the midpoint of the pelvic fins. The upper lobe of the caudal fin is large with a clear subterminal notch while the lower caudal lobe is very small. They do not have an anal fin, precaudal pit, or lateral keels.
Kitefin sharks are uniformly colored and are normally black, grey, or brown. On their dorsal side, they sometimes have indistinct black spots. The tip of their tail is black, and their fin margins are either white or transparent. On males, the tips of the claspers are often white.
While not mistaken for many other species of deep-sea shark, the kitefin shark is frequently confused with the Portuguese shark (Centroscymnus coelolepis). The key distinction between the two is the absence of spines on the dorsal fins of the kitefin shark.
In 2021, researchers confirmed speculations that the kitefin shark is bioluminescent, making it the largest known bioluminescent vertebrate. They produce a blue green light, mostly from their ventral side for counterillumination. They are also the first shark species recorded with a fully luminous dorsal fin.
Other than the females being slightly larger and the presence of reproductive claspers on males, there is no obvious sexual dimorphism. (Bester and Burgess, 2022; Chatzispyrou, et al., 2019; ERGÜDEN, et al., 2017; Kabasakal and Kabasakal, 2002; "Kitefin Shark", 2022; Kousteni, 2021; Mallefet, et al., 2021)
Kitefin sharks are ovoviviparous, so the eggs develop in the uterus of the mother, with embryos receiving nutrients from a yolk sac connected via an umbilical cord. The embryos do not develop differently from other ovoviviparous shark species. They are live at birth and are about 30 cm in length. Neonates are classified as being at or around the birth size with umbilical scars that are unhealed or healing. Once the umbilical scar fully heals/closes and can no longer be seen, they are considered post-neonatal until they reach maturity. Juvenile males are further distinguished from mature males by their uncalcified and soft claspers. (Bester and Burgess, 2022; Kabasakal and Kabasakal, 2002)
Because specimens are rarely observed live, very little is known about the mating systems and behavior of the kitefin shark.
Not much is known about the reproduction of the kitefin shark. Like most sharks, they reproduce sexually with internal fertilization. They are ovoviviparous (the eggs develop inside the mother and the young are born live). Most litters consist of 10 to 16 pups that are about 30 cm at birth. (Bester and Burgess, 2022; Kabasakal and Kabasakal, 2002)
Kitefin sharks are ovoviviparous so after fertilization, as the embryos develop in the uterus, they are protected by the mother but receive nourishment from yolk sacs. There is no parental involvement after birth. (Bester and Burgess, 2022)
Because it is a rare, deep-sea shark, little is known about the lifespan of the kitefin shark. Its generation length is estimated to be 29 years. ("Kitefin Shark", 2022)
The kitefin shark is a solitary predator. It is believed that it uses its bioluminescence for counterillumination to provide camouflage while hunting, however, it is unclear how the kitefin shark catches its prey as it has one of the slowest swim speeds recorded in sharks, clocking in at about 0.13 meters per second. One current theory is that the kitefin shark possesses a high burst speed that allows it to catch its much faster prey. (Bester and Burgess, 2022; Mallefet, et al., 2021; Pinte, et al., 2020)
There is no information on the home range of kitefin sharks in the literature.
It is unknown how the kitefin shark communicates with others. Based on where on their bodies they are bioluminescent, it is not believed that they use their bioluminescence for communication purposes.
Like all other sharks, the kitefin shark has highly refined senses. The presence of ampullae of Lorenzini (electroreceptors), concentrated in the snout, allows for electro perception. They also have a lateral line that allows them to detect vibrations and changes in water pressure. The eyes of the kitefin shark are very large, with a tapetum lucidum and a high rod density, to allow them to perceive low light levels in the deep ocean. (Bester and Burgess, 2022; Mallefet, et al., 2021; Chatzispyrou, et al., 2019; Kousteni, 2021; "Shark Senses", 2022)
The diet of kitefin sharks had been determined by analyzing the stomach contents of caught specimens. It consists mainly of small sharks; however, the kitefin shark has also been known to consume small deep-water fish, squids, octopi, shrimp, lobsters, isopods, amphipods, siphonophores, polychaetes, and tunicates. On multiple occasions, some specimens have been found to have unidentified passerine birds in their stomachs, although it is unclear how this has occurred. It is also possible that it may take small bites out of large sharks and whales as it has similar dentition to the cookie cutter shark (Isistius brasiliensis).
Other: Nephrops norvegicus (lobster), Pyrosoma atlanticum (tunicate), Paromola cuvieri (crab), unidentified Polychaeta species (bristle worms) (Barría, et al., 2018; Bester and Burgess, 2022; Chatzispyrou, et al., 2019; Dunn, et al., 2010; Kabasakal and Kabasakal, 2002; Mallefet, et al., 2021; Mulas, et al., 2021; Navarro, et al., 2014; Piscitelli and De Maddalena, 2005)
It is believed that the kitefin shark has little to no predators. While no predators have been identified, the kitefin shark may be preyed on by large deep-sea sharks and fish.
In general, sharks are high on the trophic scale and play an important role in the regulation of other species. While not much is known about the exact trophic level of the kitefin shark, it is hypothesized to be at a higher trophic level, making it a key predator in deep-sea ecosystems.
The kitefin shark is one of the known hosts of multiple species of Grillotia, a group of tapeworms that act as intestinal parasites in marine fish. (Barría, et al., 2018; Chatzispyrou, et al., 2019; Santoro, et al., 2021)
The kitefin shark is not commonly used by people, however it is fished for its squalene (oil) rich liver (mainly in Japan and South Africa), its flesh (eaten or used for fishmeal), and its skin (used to make shagreen or shark leather). (Bester and Burgess, 2022; Dunn, et al., 2010; "Kitefin Shark", 2022)
There are no known adverse effects of the kitefin shark on humans. This is because it is a deep-sea shark, making its interactions with humans limited. (Bester and Burgess, 2022)
The kitefin shark is highly vulnerable to overfishing due to its slow growth and maturation and long gestation. While it is not normally the target of fishing operations, the kitefin shark is a common bycatch/accessory species of deep-sea trawling and deep longline and gillnet fishing. Its discard mortality is unknown but assumed to be high. The kitefin shark is being caught at an increasing rate in some regions like New Zealand and Australia.
As of 2017, the kitefin shark has been considered vulnerable by the IUCN (last listed as near threatened in 2009). Over three generations (87 years), populations of kitefin sharks have declined by more than 99% in southeast Australia and 52% in the Northeast Atlantic and Mediterranean. The global population has been estimated to have declined by 30%. This rapid decline in populations is likely due to a lack of protections and the increased use of deep longline and gillnet fishing.
Not much is being done for conservation of the kitefin shark due to limited information, however there is systematic monitoring of populations in place. Europe has made some steps in protecting the kitefin shark, prohibiting the targeted fishing of the species in 2010. (Bester and Burgess, 2022; Chatzispyrou, et al., 2019; de Loyola Fernandez, et al., 2017; Dunn, et al., 2010; ERGÜDEN, et al., 2017; Kabasakal and Kabasakal, 2002; "Kitefin Shark", 2022; Kousteni, 2021; Mulas, et al., 2021)
Ally Procopio (author), Colorado State University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.
Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.
living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.
living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.
uses sound to communicate
Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
an animal that mainly eats meat
uses smells or other chemicals to communicate
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
uses electric signals to communicate
union of egg and spermatozoan
A substance that provides both nutrients and energy to a living thing.
fertilization takes place within the female's body
eats mollusks, members of Phylum Mollusca
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs develop within the maternal body without additional nourishment from the parent and hatch within the parent or immediately after laying.
generates and uses light to communicate
an animal that mainly eats fish
mainly lives in oceans, seas, or other bodies of salt water.
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.
movements of a hard surface that are produced by animals as signals to others
uses sight to communicate
2022. "Kitefin Shark" (On-line). IUCN Red List. Accessed February 20, 2022 at https://www.iucnredlist.org/species/6229/3111662.
2022. "Shark Senses" (On-line). Smithsonian Ocean Portal. Accessed March 20, 2022 at https://ocean.si.edu/ocean-life/sharks-rays/shark-senses.
Barría, C., J. Navarro, M. Coll. 2018. Feeding habits of four sympatric sharks in two deep-water fishery areas of the western Mediterranean Sea. Deep Sea Research Part 1: Oceanographic Research Papers, 142: 34-43.
Bester, C., G. Burgess. 2022. "Species Profiles: Dalatias licha" (On-line). Florida Museum. Accessed February 12, 2022 at https://www.floridamuseum.ufl.edu/discover-fish/species-profiles/dalatias-licha/.
Chatzispyrou, A., M. Aroni, E. Lefkaditou, K. Kapiris, I. Giovos, A. Anastasopoulou. 2019. Some Biological Information on a Female Kitefin Shark, Dalatias licha (Bonnaterre, 1788) Stranded in the Laconikos Gulf of Greece (SE Ionian Sea). Turkish journal of fisheries and aquatic sciences, 19: 1069.
Dunn, M., A. Szabo, M. McVeagh, P. Smith. 2010. The diet of deepwater sharks and the benefits of using DNA identification of prey. Deep Sea Research Part 1: Oceanographic Research Papers, 57: 923-930.
ERGÜDEN, D., M. ÇEKİÇ, S. ALAGÖZ ERGÜDEN, A. ALTUN, N. UYĞUR. 2017. Occurrence of adult female Kitefin shark Dalatias licha (Bonnaterre, 1788) in Iskenderun Bay (Eastern Mediterranean, Turkey). Commagene journal of biology, 1: 60-62.
Kabasakal, H., E. Kabasakal. 2002. Morphometrics of young kitefin sharks, Dalatias licha (Bonnaterre, 1788), from northeastern Aegean Sea, with notes on its biology. Annales, Series Historia Naturalis, 12: 161-166.
Kousteni, V. 2021. Morphometric description and biological notes on the rare kitefin shark Dalatias licha (Chondrichthyes: Dalatidae) from the Hellenic waters. Journal of fish biology, 99: 258-263.
Mallefet, J., D. Stevens, L. Duchatelet. 2021. Bioluminescence of the Largest Luminous Vertebrate, the Kitefin Shark, Dalatias licha: First Insights and Comparative Aspects. Frontiers in Marine Science, 8: 0. Accessed February 12, 2022 at https://www.frontiersin.org/articles/10.3389/fmars.2021.633582/full.
Mulas, A., A. Bellodi, P. Carbonara, A. Cau, M. Marongiu, P. Pesci, C. Porcu, M. Follesa. 2021. Bio-Ecological Features Update on Eleven Rare Cartilaginous Fish in the Central-Western Mediterranean Sea as a Contribution for Their Conservation. Life, 11: 871.
Navarro, J., L. López, M. Coll, C. Barría, R. Sáez-Liante. 2014. Short- and long-term importance of small sharks in the diet of the rare deep-sea shark Dalatias licha. Marine Biology, 161: 1697-1707.
Pinte, N., P. Parisot, U. Martin, V. Zintzen, C. De Vleeschouwer, C. Roberts, J. Mallefet. 2020. Ecological features and swimming capabilities of deep-sea sharks from New Zealand. Deep Sea Research Part I: Oceanographic Research Papers, 156: 0. Accessed April 13, 2022 at https://doi.org/10.1016/j.dsr.2019.103187.
Piscitelli, L., A. De Maddalena. 2005. Evidence of a predatory attack on a large paromola, Paromola cuvieri (Risso, 1816), by a kitefin shark, Dalatias licha (Bonnaterre, 1788). Thalassia Salentina, 28: 3-8.
Santoro, M., B. Bellisario, F. Crocetta, B. Degli Uberti, M. Palomba. 2021. A molecular and ecological study of Grillotia (Cestoda: Trypanorhyncha) larval infection in small to mid-sized benthonic sharks in the Gulf of Naples, Mediterranean Sea. Ecology and Evolution, 11: 13744-13755.
de Loyola Fernandez, I., J. Carlos Baez, S. Garcia-Barcelona, J. Antonio Caminas, J. Ortiz de Urbina, D. Macias. 2017. Length-Weight Relationships of Kitefin Shark Dalatias Licha, and Little Sleeper Shark Somniosus rostratus from the Western Mediterranean Sea, and Long Snouted Lancetfish Alepisaurus ferox from the Eastern North Atlantic Ocean. Turkish journal of fisheries and aquatic sciences, 17: 1073-1076.