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The California moray (Gymnothorax mordax) is a moray eel of the family Muraenidae, found in the eastern Pacific from just north of Santa Barbara to Santa Maria Bay in Baja California.[1] They are the only species of moray eel found off California, and one of the few examples of a temperate moray. They typically occupy boulder or cobble habitats up to 40 m in depth.[2] They can attain lengths of about 5 ft (1.52 m) and are believed to live for upwards of 22–26 years.[3] Like other morays, they have no pelvic or pectoral fins or gill covers.

California moray
California moray.jpg
Scientific classification edit
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Anguilliformes
Family: Muraenidae
Genus: Gymnothorax
G. mordax
Binomial name
Gymnothorax mordax
(Ayres, 1859)

California morays are a common sight on rocky reefs surrounding islands in southern California (notably, Catalina Island in the California Channel Islands) and other islands in the Pacific[1]. However, at least one study has proposed that this species is non-reproductive in the most northern parts of its range due to the water temperature being too cold for gonadal development.[4] A more recent study aged morays from Catalina Island using their otoliths (ear bones) and found that the majority of individuals examined likely arrived on Catalina Island during an El Nno Southern Oscillation (ENSO) event,[3] supporting the hypothesis that spawning populations are found further south. During an ENSO event, the southward-flowing California Current slows down and moves offshore, allowing the northward-flowing Davidson Current to bring leptocephalus larvae to northern areas.

Feeding behaviorEdit

California morays mainly eat fish, although they are opportunistic predators whose diet also consists of invertebrate prey such as octopuses, lobsters, and shrimp. Interestingly, it appears that California morays will share habitat space with potential prey species, including both shrimp and lobsters.[5] Like other morays, California morays have a special set of pharyngeal jaws that allows prey to be transported from their mouths into their throats. As an additional aid to prey transport, they have a set of depressible teeth in the roof of their mouths that fold upward as prey is swallowed.[6]

No relationship has been found between prey size and moray size, suggesting that California morays will continue to eat small prey even as they themselves get larger.[6] They are apex predators in the reef, with few predators of their own. California morays are not commercially fished.


  1. ^ a b Fitch, John E.; Lavenberg, Robert J. (1971). Marine Food and Game Fishes of California. University of California Press. ISBN 9780520018310.
  2. ^ Higgins, B. A.; Mehta, R. S. (2018-01-01). "Distribution and habitat associations of the California moray (Gymnothorax mordax) within Two Harbors, Santa Catalina Island, California". Environmental Biology of Fishes. 101 (1): 95–108. doi:10.1007/s10641-017-0684-0. ISSN 0378-1909.
  3. ^ a b Higgins, B. A.; Pearson, D.; Mehta, R. S. (2017-01-31). "El Niño episodes coincide with California moray Gymnothorax mordax settlement around Santa Catalina Island, California". Journal of Fish Biology. 90 (4): 1570–1583. doi:10.1111/jfb.13253. ISSN 0022-1112. PMID 28138961.
  4. ^ "The ecology and behavior of the California moray eel gymnothorax mordax (Ayres, 1859) with descriptions of its larva and the leptocephali of some other east pacific muraenidae :: University of Southern California Dissertations and Theses". Retrieved 2018-05-09.
  5. ^ Poulin, Robert; Grutter, Alexandra S. (1996). "Cleaning Symbioses: Proximate and Adaptive Explanations". BioScience. 46 (7): 512–517. doi:10.2307/1312929. JSTOR 1312929.
  6. ^ a b Harrison, Jacob S.; Higgins, Benjamin A.; Mehta, Rita S. (2017-06-01). "Scaling of dentition and prey size in the California moray (Gymnothorax mordax)". Zoology. 122: 16–26. doi:10.1016/j.zool.2017.02.002. ISSN 0944-2006. PMID 28236504.

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