Greenland Shark
(Somniosus microcephalus)
Key Features/Appearance
Greenland Sharks are large, thick-bodied with short dorsal fins of similar size and no anal fin. Adults average 2.5m to 4.5m (8 to 15 ft) in length, with a maximum length of 7.3m (24 ft). They may reach a weight of 1000 kg (2200 lbs) but generally average 800-900kg (1760-1980 lbs). These sharks can vary is color from black to brown to grey, or a combination of all three. They may also have dark and/or light blotches and spots. Its upper teeth are pointy and longer than its lower teeth which are wider, flatter and curved.
Greenland sharks are commonly seen with copepods on their eyes. These parasites, called Ommatokoita elongata, latch on to the shark's eye and destroy the corneal tissue, leaving the shark partially blind. . In some populations, 90% of Greenland sharks carry these parasites.
Habitat and Distribution
The Greenland shark is a deep, cold water shark that inhabits the North Atlantic and the Arctic oceans, in water temperatures ranging between 1 and 12 degrees Celsius (34̊-54̊ F). They’re commonly located at depths of 1,200 meters (3,937 ft). Their range in the North Atlantic extends from the Gulf of St. Lawrence off Newfoundland, Canada to Cape Cod, Massachusetts, USA.
Diet
This slow swimming shark species is an opportunistic feeder, consuming a wide variety of prey. They are a scavenger, eating most anything they find, whether it’s alive or dead. The following are some confirmed stomach contents: Fish, Seals, Moose, Porpoise, Beluga Whales, Narwhals,
Crustaceans, Jellyfish, Octopus, Snails.
Reproduction
Very little is known about the reproduction of Greenland sharks. It is believed they reproduce through aplacental viviparity , where eggs are hatched inside the female, developing from the nutrients of the egg sacs until they are ready to be birthed live. The average litter size is 10 pups. Known to be the longest-lived vertebrate on the planet, with estimates over 400 years old, it’s suspected they do not reach sexual maturity until at least 100 years old.
Status
The Greenland shark is listed as “Near Threatened” on the IUCN Red List of Threatened Species.
Threats
Sperm Whales and humans are the only known predators of the Greenland shark. They are hunted for their liver oil and are killed as bycatch in commercial fisheries.
ARTICLE about research being done by scientist Julius Nielsen
References
Shark Research Institute
https://www.sharks.org/greenland-shark-somniosus-microcephalus
Greenland Shark & Elasmobranch Education & Research Group
https://geerg.ca/greenland-shark/
Canadian Geographic
https://www.canadiangeographic.ca/article/animal-facts-greenland-shark
The IUCN Red List of Threatened Species. https://www.iucnredlist.org/search?query=greenland%20shark&searchType=species
Kyne, P.M., Sherrill-Mix, S.A. & Burgess, G.H. 2006. Somniosus microcephalus.
The IUCN Red List of Threatened Species 2006: e.T60213A12321694. http://dx.doi.org/10.2305/IUCN.UK.2006.RLTS.T60213A12321694.en.
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