Ocean Creatures
by Carol Georgi
Hello Ocean Lovers! Every Other Breath is From the Ocean
Here are some critters from our San Luis Obispo County coastal waters for you to enjoy!
Thank you for your interest in the Central Coast Extension of the Monterey Bay National Marine Sanctuary.
Information provided here is "According to the Monterey Bay Aquarium"
Sevengill Shark Notorynchus cepedianus
Growing up to 10 feet long (3 m), the sevengill shark has a wide head with a blunt nose and only one dorsal (top) fin (most sharks have two), and seven pairs of gill slits (most sharks have five). Its back and sides are reddish brown to silvery gray, or olive-brown and speckled with many small black spots, and its underbelly is cream colored.
The teeth on this shark’s lower jaw are comb shaped, and the teeth in the upper jaw are jagged. When biting large prey, the shark anchors its jaw with the lower teeth, and then thrashes its head back and forth to saw off pieces of flesh with the upper teeth.
Sevengill sharks prowl for food in shallow inshore waters, and they appear in deeper waters along the continental shelf. These sharks prey on almost anything, including octopuses, rays, other sharks, bony fishes and carrion, and may hunt in packs for seals. They are powerful swimmers that can be aggressive if provoked, and are considered potentially dangerous to humans.
During March, 2010, two sevengill sharks were caught in Shell Beach. After each catch, harbor seals were seen in the water.
Swell Shark Cephaloscyllium ventriosum
Growing up to 3 feet (1m) long, the swell shark gets its name because, if threatened, the swell shark bends its body into a sharp U-shape, grasps its caudal fin in its mouth and swallows a large quantity of sea water, which makes it swell to twice its normal size. Sharks are cartilaginous fish; their skeletons have no bones. Cartilage is less dense and more elastic than bone, giving sharks increased maneuverability.
Brown blotches and white spots decorate a swell shark’s yellow-brown body. By day, this small, harmless and well-camouflaged shark hides in rocky crevices. By night, a swell shark feeds. It actively sucks in some fishes; it captures others by resting open-mouthed and letting prey wander in or be carried in by currents.
People don’t catch swell sharks for food, but the sharks are caught accidentally as by-catch in commercial lobster and crab traps, gillnets and trawl nets. Because sharks take five to 20 years to mature and have few young, accidental catches like these threaten shark populations around the world.
Submitted by Carol Georgi, Volunteer Santa Lucia Sierra Club, Slo Surf Rider, Save Our Seas
Images and information provided by the Central Coast Extension of the Monterey Bay National Marine Sanctuary. Some photos by Terry Lilley with Sue Sloan doing the lighting. Terry is sharing his photos to encourage interest in the marine sanctuary effort. Contact Carol to be added to the "Critter of the Week" email list. |
