California Moray Eel
Gymnothorax mordax

Physical Description

• A long, flattened, snakelike fish.
• Light to dark brown or green coloration, often mottled.
• No dorsal fins, no tail fin, no gill cover.
• They have no scales, unlike other fish. They are covered in a yellowish mucus that protects their skin instead.

Range

• Point Conception, California to southern Baja California, Mexico.

Habitat

• Live in rocky reefs. They often hide in rock crevices all day and hunt at night.
• Also found in pier pilings.
• Juvenile moray eels live in the tide pools, adults live in deeper water.

Reproduction

• They breed by broadcast spawning in warm waters.
• Scientists have thought that moray eels do not reproduce off of Southern California, because the water is too cold. They have thought they are born off Baja and drift up here. But Katherine Dale at UC Santa Cruz is using genetics to determine if this is true or not.
• After moray eels spawn, the eggs hatch into larvae that may drift in the currents for up to 12 months before settling to the bottom.

Diet

• Small reef fish, octopuses, shrimp, crabs, lobsters, sea urchins.

Predators

• Other, larger moray eels.
• Marine mammals.
• Groupers will both hunt with moray eels and hunt moray eels! (although this hasn’t been shown with California morays).

Interesting Facts

• Most fish breathe by constantly opening and closing their gill covers to force water over their gills. Since moray eels don’t have gill covers, they must constantly open and close their mouths! 
• Moray eels have two sets of jaws! Their first jaws clench down on the food, and then the second jaws lunge forward and grab the prey and pull it into the throat! 

Sources: Monterey Bay Aquarium; spotmydive.com; moraeels.weebly.com; Katherine Dale, UC Santa Cruz; Mehta and Wainwright 2007; Aquarium of the Pacific

Photo: David R. Andrew

See if you can spot moray eels on Birch Aquarium’s Kelp Cam! They’re almost always on the left side of the tank!