March 2015 Shark of the Month: Basking Shark
Name: Basking Shark. Scientific Name: Cetorhinus maximus
Key Features: The Basking Shark is a brownish gray in color, and sometimes its large dorsal fin is confused with that of a Great White shark. It has two, very specific morphological traits used to help with identification; it’s enormous size and it’s pointed, conical snout. It is the second largest shark species (behind the Whale Shark) and can grow to 32-39 feet in length! The Basking Shark also has a very distinctive long and cone-shaped snout, which is found right above it’s very wide (and usually open) mouth. The mouth is surrounded by five gill slits on each side, so long that they almost encircle the shark’s head!
Where it’s found: No matter where you live in the world, as long as you’re near an ocean- you might see a Basking Shark! They are found all over the world, usually swimming close to the surface and prefer cold to warm-temperate water. The Basking shark got its name due to its tendency to be seen “basking” at the ocean’s surface. Large Basking Shark aggregations can be seasonally found off the Gulf of Maine and around Scotland.
Diet: Even though the Basking Shark is larger than a Great White shark, it has more in common with the world’s largest shark, the Whale Shark. Like the Whale shark, Basking sharks feed on plankton and can usually be found slowly, swimming at the water’s surface with their mouths wide open, in order to help them filter water and capture plankton for food. This kind of behavior is called “ram-feeding” and allows high volumes of water to pass by their gill rakers, which catches the plankton. In the colder, winter months, the Basking shark will feed at much deeper and darker depths on deepwater zooplankton.
Conservation Status: IUCN Red list- Vulnerable, CITES Appendix II. Threats: In the past, Basking sharks were targeted by fishermen for their large oily livers, which was used as fuel for oil lamps, and also for engineering oil and cosmetics. More recently, Basking shark populations have declined due to their tendency to be caught as bycatch in gill and trawling nets from fisheries. Basking sharks are also illegally targeted for their large fins as part of the shark fin soup trade. Since female Basking sharks only give birth to 1-6 young, it’s very hard for their populations to recover once their numbers have declined.
FINtastic Fact: Basking sharks can actually breach clear out of the water, much like the Great White shark! It is thought that the breaching behavior is part of a social or courtship interaction among other Basking sharks, or possibly to help rid it’s dermal denticles of pesky copepods and parasites.