Mermaid’s Purse

California Swell Shark (Cephaloscyllium ventriosum) Mermaid’s Purse

Contributed by TPERP Dan Wieder

Mermaids Purse

Where to find them: California swell sharks are found from Central California to the Gulf of California in shallow water near rocky reefs and kelp beds. Their egg sacks (Mermaid’s Purse) can grow to an average size of 10 cm.

What do they eat: They are nocturnal, feeding on bony fishes, molluscs and crustaceans.

Who eats them: Its predators include seals and larger sharks. It can expand its body to almost double its size to prevent predators from eating it.

Adaptations: As with most sharks, this species adapts well to its mode of life. Good vision, especially for its nocturnal activities, sensitive olfactory abilities, and sensitivity to minute electric fields created by other animals provide it with the potential for food gathering and protective activities. Its coloration and marking patterns provide excellent camouflage to hide it from predators.

Reproduction: The Swell shark is oviparous, laying two flattened egg cases that it attaches to the reef with long tendrils that extend from one end. These egg sacks are commonly referred to as Mermaid’s Purse.

What is their life like: Swell sharks rest during the day in caves and rocky crevices and then venture out to hunt at night.

Interesting Facts: When confronted by a human in the water, the swell shark will become motionless. If it is threatened it will swell up to double its size.

Phylum: Chordata
Class: Chondrichthyes
Order: Carcharhiniformes
Family: Scyliorhiniformes

Sources of Information:

Last revised 12-Dec-19