Smooth Stargazer, Kathetostoma averruncus

Smooth Stargazer, Juvenile, Kathetostoma averruncus. Provided by the commercial fishermen of the greater Los Cabos area, April 2011. Length: 4.5 cm (1.8 inches). Identification courtesy of Dr. Phil Hastings, Scripps Institution of Oceanography, La Jolla, California.

Smooth Stargazer, Kathetostoma averruncus, Juvenile. Fish caught from coastal waters off Point Palmilla, Baja California Sur, February 2020. Length: 13 cm (5.1 inches).

Smooth Stargazer, Kathetostoma averruncus. Provided by the commercial fishermen of the greater Los Cabos area, June 2014. Length: 23.0 cm (9.1 inches). Identification courtesy of Dr. Phil Hastings, Scripps Institution of Oceanography, La Jolla, California.

Smooth Stargazer, Kathetostoma averruncus. Provided by the commercial fishermen of the greater Los Cabos area, April 2011. Length: 27 cm (11 inches). Identification courtesy of Dr. Phil Hastings, Scripps Institution of Oceanography, La Jolla, California.

The Smooth Stargazer, Kathetostoma averruncus, is a member of the Stargazer or Uranoscopidae Family, and known in Mexico as miracielo buldog. Globally, there are seven species in the genus Kathetostoma, of which three are found in Mexican waters, two in the Atlantic and this species in the Pacific Ocean.

The Smooth Stargazer has a short thick body that tapers toward the rear. They are dark green, brown, or gray dorsally and transition to light brown ventrally. They have white spots on their head and larger white spots and blotches on their body. Their caudal, dorsal, and pectoral fins have white margins. The tips of their opercular spines are yellow. They have a large square head with large eyes and a large vertical mouth. A key to identification is a pair of large venomous spines at the upper edge of their operculum (clearly visible in photographs below); they also have three non-venomous spines on the lower edge of their gill covers. Their anal has no spines and 12 to 18 rays; their dorsal fin has no spines and 13 to 18 rays; their pectoral fins are very large; and, their pelvic fins are large. They do not have scales.

The Smooth Stargazer is a solitary benthic coastal species normally found submerged in substrate (beaches, sand bottoms, and soft bottom habitats in mangroves and estuaries) at depths between 12 m (40 feet) and 610 m (2,000 feet). They reach a maximum of 32 cm (13 inches) in length. They are ambush predators that lie in wait with only their eyes exposed; they consume small invertebrates and small fish. Juveniles are pelagic and eaten by large predatory fish such as tuna. The Smooth Stargazer 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 Smooth Stargazers is a resident of all Mexican waters of the Pacific Ocean with the exception that they are absent from the northern two-thirds of the Sea of Cortez.

The Smooth Stargazer can be confused with the Pacific Stargazer, Astroscopus zephyreus (larger; small eyes; no large white spots).

From a conservation perspective the Smooth Stargazer is currently considered to be of Least Concern with stable, widely distributed populations. They are prone to habitat loss from coastal development. They are a mid-sized fish but seldom seen by humans and of limited interest to most. They are used on a limited basis by the aquarium trade. A word of caution! The Smooth Stargazers have a pair of large poisonous spines and therefore should be handled with extreme caution.