This Sunday Discovery kicks off Shark Week 2017. While Shark Week has arguably gone down hill in recent years, one of the few episodes I am actually looking forward to this year is Alien Sharks: Stranger Fins. This episode features scientists from the Pacific Shark Research Center including Dr. David A. Ebert and Victoria (Vicky) Elena Vásquez, a member of Gills Club. This episode also features deep sea species that are rarely featured in shark documentaries, including our featured shark species of the week: the Goblin Shark (Mitsukurina owstoni).
Discovery. (14 July 2017). HD Discovery Alien Sharks 2017 Trailer [Video Clip]. Retrieved from https://www.facebook.com/Discovery
The goblin shark, also known as the elfin shark (Frederico & Hassall, 1998), is what is known as a “living fossil” (Parker, 2008). The species was first described in 1887 by a fossilized teeth that dated back 100 million years (Parker, 2008; Mojetta, 1997). Then just ten years later in 1897 off Yokohama, Japan the first goblin shark was caught when it damaged a submarine telegraph cable (Parker, 2008). The specimen was brought to Kakichi Mitsukuri, who then transported the shark from Japan to the United States to Professor David Starr Jordan. It was Prof. Jordan who cataloged and named the shark Mitsukurina owstoni (Mojetta, 1997). According to the Zoological Nomenclature Rules the goblin shark should have been named after the fossilized specimen genus: Scapanorhynchus. However a compromise was reached so that both names could be kept: Scapanorhynchus for the extinct genus and Mitsukurina for the extant genus (Mojetta, 1997).
Since the first discovery of the goblin shark, sightings have been rare. They are almost as rare as the megamouth shark (Megachasma pelagios). Much of what is known about these sharks actually comes from dead specimens that have been caught in fishing nets. The goblin shark is known for two distinct features: the long, blade-like snout, and the unusually distended jaws. The snout contains the ampullae of Lorenzini, little specialized jelly-filled pores that are actually a sensing organ called electroreceptors. This allows sharks to sense their prey’s vibrations from a distance and low visibility. While all sharks have this sense, it is thought that the elongated snout gives the goblin shark an advantage in the very low light to total darkness it usually inhabits (Skomal, 2016).
The other characteristic the goblin shark is known for is definitely unusual: the distended jaw. When first discovered, the dead specimen’s jaw hung down incredibly low, almost bulging from the skull (Parker, 2008). When the goblin shark was observed alive it was realized the jaw typically sits flush against skull. Once prey is detected, the jaws snap forward and down, trapping prey behind their needle-like teeth (Skomal, 2016).
Slow Motion Capture
Goblin Shark Jaw gif [Digital Image] (n.d.). Retrieved from https://tumblr.com/
Real Time Capture
Goblin Shark Jaw gif [Digital Image] (n.d.). Retrieved from https://earthtouchnews.com/
The goblin shark has unique skin for a shark. Most sharks have relatively thick skin. Some sharks, like the whale shark (Rhincodon typus), can have skin inches thick. But the goblin shark has a semitransparent skin covering many small blood vessels. This makes the shark appear pale pink, blue, or a sickly grayish tone. Because the blood vessels are so close to the surface, the goblin shark is prone to bruising easily (Parker, 2008).
Family: Mitsukurinidae; 1 species
Length: Up to 13 feet (3.9 m)
Weight: 460 lbs (210 kg)
Habitat: Deep sea continental and island shelves; oceanic waters.
Depth: 300 to 4,000 feet (91 to 1219 m)
Reproduction: Unknown but suspected to be Ovoviviparous
Gestation: Unknown. No pregnant female has ever been seen.
Litter Range: Unknown
Home Range: Patchy distribution in tropical to cool temperate waters.
Diet: Deep water bony fishes and invertebrates.
IUCN Status: Least Concern
(Skomal, 2016; Parker, 2008; Duffy, Ebert, & Stenberg , 2004)
Hope you enjoyed this week’s Featured Species! If you missed last week be sure to check out the Common Thresher Shark. Feel free to leave me your comments, questions, or feedback! If there’s a species you’d love to see featured, leave me a comment! I’d love to know what species you’d like to know more about. Remember you can make a difference for marine ecosystems by calling your Congress man or woman and tell them that you care about the quality of our waters! Sharks, rays, and other marine organisms cannot speak or be represented in Congress. They need your voice. Get involved and stand up for sharks.
Featured Image Source
Finn, J.K. (Photographer). (June 2012). Head of a juvenile Goblin Shark, Mitsukurina owstoni, from off western Tasmania [Digital Image]. Retrieved from http://fishesofaustralia.net.au/home/species/3254
Duffy, C.A.J., Ebert, D.A. & Stenberg , C. 2004. Mitsukurina owstoni. The IUCN Red List of Threatened Species 2004: e.T44565A10907385.
Frederico, L., & Hassall, G. (Eds.). (1998). Reader’s Digest Explores: Sharks (1st ed.). Reader’s Digest.
Mojetta, A. (1997). Sharks: History and biology of the lords of the sea. (E. McNulty, Ed.). San Diego: Thunder Bay Press.
Parker, S. (2008). The encyclopedia of sharks (2nd ed.). Buffalo, NY: Firefly Books Ltd.
Skomal, G. (2016). The Shark Handbook: The Essential Guide for Understanding the Sharks of the World. (2nd ed.). Kennebunkport, ME: Cider Mill Press.