Ron's Critter of the Day

TAXONOMY
Kingdom: Animalia
Phylum: Chordata
Class: Elasmobranchii (sharks and rays)
Order: Carcharhiniformes (Ground sharks; characterized by the presence of a nictitating membrane over the eye, two dorsal fins, an anal fin, and five gill slits.)
Family: Scyliorhinidae (Cat sharks; elongated cat-like eyes and a patterned appearance, ranging from stripes to patches to spots)

Genus/species: Cephaloscyllium ventriosum

GENERAL CHARACTERISTICS: Swell sharks have a stout body with flat, broad head; short snout; huge mouth,  proportionally larger that the great white shark (Carcharodon carcharias). Teeth are at front of jaws with dagger-like central point and 1-2 small points on each side; two dorsal fins: first much larger, with origin over pelvic fins, second dorsal fin considerably smaller than first, its origin over origin of anal fin. The body is light brown with dark patches covered with black dots.

Length up to 3.2 ft.

DISTRIBUTION/HABITAT: Central California to southern Mexico; also reported near central Chile.
Found in rocky reefs and kelp forests, from surface to 460 m (1500 ft), in temperate and subtropical waters.

DIET IN THE WILD: C. ventriosum is nocturnal; feeding on crustaceans and fishes, (often blacksmiths). They are lie-in-wait predators that sit on the bottom with wide-open mouth, ready to ambush unsuspecting prey. (slowly opens jaws; lies in wait for prey to swim inside).

egg case above

REPRODUCTION: Oviparous; female lays amber-colored egg cases that hatch in 8–10 months. Egg case (“mermaid’s purse”) is 9 – 13 centimeters (3.5 – 5 inches) long, 3 – 6 centimeters (1 – 2.3 inches) wide. Young have enlarged toothlike denticles on the back that help them break through egg cases. Pups measure 14 – 15 centimeters (5.5-6 in) at birth; immediately feed on their own.

Embryos may be eaten by snails that bore through egg cases.

Pup  below on top of egg case

PREDATORS:  If caught it is, usually it will be released because its flesh is of poor quality.    Life span: 25 or more years.

CONSERVATION: IUCN Red List: least concern species

REMARKS: C. ventriosum hides in caves and crevices during normal aquarium hours. the day, and so is often not to be seen during aquarium hours. Common and specific (ventriosum = “largebelly”) names come from its ability to take in water that makes it appear up to twice as large as its normal size, a difficult meal for predators to bite or to remove from a crevice. If caught and brought to the surface, it can swell its body with air.

When caught by fishermen and brought out of water, the release of gulped water/air can cause the swell shark to “bark”.

Occurs in aggregations while resting, sometimes piled one on top of the other.

Southern California Coast Kelp Exhibit Tidepool young with egg cases.

References

California Academy of Sciences Steinhart Aquarium Southern California Coast Kelp Exhibit 2018

Ron’s WordPress shortlink wp.me/p1DZ4b-XL

Ron’s flickr 7608440813109/www.flickr.com/photos/cas_docents/14479061579/in/set-7215

fishbase www.fishbase.org/summary/802

Marine bio.org marinebio.org/species.asp?id=383

 eol eol.org/pages/208742/details

Sean Donahoe, CAS docent, materials from the Naturalist Center and collaborated with Docent Program staff document.

Works Cited

1. Carwardine, M. 2004. Shark. Firefly Books. Buffalo. 168 p.

2. Michael, S.W. 1993. Reef Sharks and Rays of the World: A guide to their

identification, behavior, and ecology. Sea Challengers. Monterey. 107 p.

3. Parker, S. and Parker, J. 1999. The Encyclopedia of Sharks. Firefly Books.

Buffalo. 192 p.

4. Ebert, D.A. 2003. Sharks, Rays, and Chimeras of California. University of

California Press. Berkeley/Los Angeles. 284 p.

5. Springer, V.G. and Gold, J.P. 1989. Sharks in Question. Smithsonian Institution

Press. Washington, D.C. 187 p.