OSTEICHTHYES: ANGUILLIFORMES: MURAENIDAE: Gymnothorax

Gymnothorax castaneus (Jordan and Gilbert, 1883)

Yellow or Panamic Moray

Photos and text by Robert George Sprackland, Ph.D.

Range: The rocky and corral reefs of the Sea of Cortez (Gulf of California) and warm coastal waters western Mexico.

Diagnosis:

Description: Like other morays, this species is distinguished from other eels in lacking pectoral or pelvic fins. The dorsal fin is contiguous with the "tail" and ventral fins. There is no operculum (gill cover), but instead a semicircular gill hole that is slightly larger than the eye. The eye and nostril are round. The nostril sports two tiny fleshy "tentacles." The body is yellow to light olive green with no markings.

Natural History: Morays are crevice dwellers, inhabiting narrow fissures in coral reefs and rocky ledges. From a position of concealment they can dart forward with great speed and capture the fishes and small crustaceans upon which they feed. They are generally found in warm shallower coastal waters.

Morays are not venomous, but a bite from a large specimen can be extremely painful and is likely to become septic unless properly treated. Morays are curious and will often approach divers. When divers try to feed the morays, they stand the greatest chance of being bitten.

Reproduction:

Taxonomy & Relationships: The family Muraenidae is part of the Angulliformes, a cluster of 15 families encompassing some 780 species of true eels. They are among the most ancestral of the teleost fishes.

Variation:

Additional Comments: Morays, though commonly called eels, are actually quite distinct from "true" eels. Unlike eels, morays have gill holes instead of operculum-covered gill slits, and lack pectoral fins.

Type Specimen: Lectotype: USNM 29591.

Literature: