The Fins United Initiative is excited to bring back the loved "Underrated Elasmobranch Spotlight" series through TFUI officer Jess Myers. Learn about the Chondrichthyans not shown on the big screen through her beautiful artwork... and check out the new name.
The underrated elasmobranch line up is back for its 5th year and I am so excited to showcase some amazing creatures this week.
Let’s start out with an unusual shark species, the crocodile shark (Psuedocarcharias kamoharai), also known as the Japanese ragged-tooth shark and water crocodile. They are given this name for their sharp teeth and habit of snapping their jaws when caught. Crocodile sharks are typically about 1 to 1.2 meters (3 – 4 feet) in length. Females only give birth to at most 4 pups. In some fisheries, the shark is considered bycatch since its meat isn’t the tastiest. However, they are sometimes used for their large, squalene-rich livers. Squalene is an oily substance commonly added to cosmetics and supplements.
Crocodile sharks can be found in open, tropical waters all around the world, but they aren’t seen too often. They stay in deeper waters (~600 m) during the day, waiting until nightfall to venture near the surface to feed. Crocodile sharks don’t do this on their own, thousands of animals participate in the greatest migration in the world known as the diel or diurnal vertical migration (DVM). Their large, buoyant liver aids them in their ascent to the surface each night.
You probably noticed the massive eyes on this species. Large eyes are a common feature in deep sea fish to help them see in such a dark environment. If you’ve ever had your eyes dilated, you know how sensitive they can get! With their small size and cigar-shaped bodies, crocodile sharks look like they’re most closely related to cookie cutter sharks (Isistus braziliensis) or some dogfish shark, but with some genetic testing scientists placed these sharks in the order Lamniformes (mackerel sharks). They are the only species in their family Psuedocarchariidae because of their uniqueness. Scientists are still trying to determine if they are more closely related to thresher sharks (Alopiidae), megamouth sharks (Megachasmidae), or sand tiger sharks (Odontaspididae).
Crocodile sharks are considered harmless to humans. Since they aren’t targeted heavily by fisheries, this species is ranked Least Concern by the IUCN Red List in their latest survey (2018).
WHAT UNDERRATED CHONDRICHTHYAN DO YOU THINK SHARK WEEK SHOULD SHOWCASE?
TFUI Founder Melissa C. Marquez is author of all animal bios and "Behind the Fins" segments.
SEE MELISSA'S TEDx TALK HERE:
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