Spottail Moray, Gymnothorax equatorialis
Spottail Moray, Gymnothorax equatorialis. Fish caught off Point Palmilla, Baja California Sur, March 2016. Length 40 cm (16 inches). Tail: 53%.
Spottail Moray, Gymnothorax equatorialis. Fish caught off Point Palmilla, Baja California Sur, September 2022. Length 45 cm (18 inches). Tail: 54%.
Spottail Moray, Gymnothorax equatorialis. Fish caught off Point Palmilla, Baja California Sur, April 2011. Length 71 cm (28 inches). Tail: 53%.
The Spottail Moray, Gymnothorax equatorialis, is a member of the Moray and Snake Moray Eel or Muraenidae Family, that is also known as the Equatorial Moray and in Mexico as morena cola pintada. Globally, there are one hundred sixteen members in the genus Gymnothorax, of which eighteen are found in Mexican waters, nine in the Atlantic and nine in the Pacific Ocean.
The Spottail Moray has a stout elongated compressed body that tapers to a narrow tail with a slender tip. They are dark brown and transition to light tan ventrally. They have very elongated small white spots on their head, which become larger toward the rear of their body. The spots at the base of their tail is the key to identification; they are very elongated, longer than eye diameter, and widely spaced. Their anal fin has a dark black margin. The traditional black spot on the gill covers of many Morays is not readily visible in this species. Their head is rounded with a short blunt snout and large eyes. Their front nostrils have tubes and their rear nostrils are flush with the head profile. They have a large mouth equipped with enlarged “shark-like” teeth that are triangular and curved in shape with serrated rear edges; their teeth are present as a single row on each jaw. Their anal and dorsal fins are very low, covered with skin, and continuous with the caudal fin; their dorsal fin originates in front of the gill openings. Their tail is approximately half or slightly greater than half the body length. They do not have pectoral fins or scales. They are covered with thick yellow mucus, which provides them with protection from abrasion.
The Spottail Moray is found over soft sandy bottoms adjacent to rocky reefs from the intertidal zone to depths of 183 m (600 feet). They reach a maximum of 1.0 m (3 feet 3 inches) in length with females being slightly larger than males. During the day they back into crevices within rock structure leaving only their head protruding. Their body shape and lack of fins, scales, or gill covers allow them to move quickly in and out of rocky crevices. They are voracious nocturnal ambush predators with poor eyesight that utilize their keen sense of smell to seek out prey, consuming small fish and invertebrates including crab, octopus, and shrimp. They open and close their mouth frequently, an action required for respiration. Reproduction is viviparous with eggs and sperm broadcast into the water generating pelagic eggs and larvae that drift in oceanic currents before settling out on the bottom. Each females releases an average of 32,000 eggs per year. The Spottail Moray is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.
The Spottail Moray is a resident of all Mexican waters of the Pacific Ocean with the exception that they are absent from the entire west coast of Baja. However I have collected a fish 40 miles north of Cabo San Lucas, extending the known range for the species, indicating that they can probably be found as far north as Magdalena Bay, Baja California Sur, along the Pacific coast.
The Spottail Moray can be confused with the Finespotted Moray, Gymnothorax dovii (small white spots covering head and body) and the Many-spotted Moray, Gymnothorax phalarus (deeper tail with round or oval spots that are close together and less than eye diameter) .
From a conservation perspective the Spottail Moray is currently considered to be of Least Concern with stable, widely distributed populations. They are very seldom, seen by humans. When encountered they are visually most intimidating but are very timid and not harmful and are only known to bite humans on rare occasions. They are caught on occasion by recreational anglers out of heavy rock structure and normally a “catch and release”. They are also a fairly common catch of deepwater shrimp trawlers.