Sonora Blenny, Malacoctenus gigas

Sonora Blenny, Malacoctenus gigas. Fish caught from coastal waters off Puertecitos, Baja California, July 2012. Length: 7.6 cm (3.0 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

Sonora Blenny, Malacoctenus gigas. Fish caught from coastal waters off Puerto Peñasco, Sonora, November 2020. Length: 7.9 cm (3.1 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Sonora Blenny, Malacoctenus gigas, Female. Fish caught from coastal tidal pools on Los Conchas Beach, Puerto Peñasco, Sonora, April 2021. Length: 11.2 cm (4.4 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.

Sonora Blenny, Malacoctenus gigas, Male. Fish caught from coastal tidal pools on Los Conchas Beach, Puerto Peñasco, Sonora, April 2021. Length: 11.5 cm (4.5 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.

The Sonora Blenny, Malacoctenus gigas, is a member of the Labrisomid Blenny or Labrisomidae Family, that is known in Mexico as trambollo de Sonora and trambollo veteado. Globally, there are eighteen species in the genus Malacoctenus, of which fourteen are found in Mexican waters, six in the Atlantic and eight in the Pacific Ocean.

The Sonora Blenny has an elongated oval fusiform shaped body. They are green dorsally that transitions to white on the breast and belly with four or five irregular dark brown bars on the sides. They are sexually dimorphic with males having uniformly dusky anal, caudal and dorsal fins and females having spotted caudal and dorsal fins and their lower flanks covered with a reticulated pattern of dark lines. Their head is slender with a pointed snout with a small mouth that opens at the front that is equipped with large teeth set in a row on the upper jaw. They have one close set pair of heavily branched cirrus on the nape and a branched cirrus over the eyes. Their anal fin has 2 spines and 20 to 24 rays; their caudal fin is rounded; their first dorsal fin has 19 to 23 spines; their second dorsal fin has 12 to 14 rays; their pectoral fin has 13 to 15 rays; and, their pelvic fins have 3 rays. They are covered with smooth scales.

The Sonora Blenny is a small shallow water coastal species found within coral and rocky reefs among seaweed at depths up to 5 m (16 feet). They reach a maximum of 13 cm (5.1 inches) in length. They feed on crustaceans. Reproduction is oviparous with females depositing eggs in protected areas that are defended by the males. The Sonora Blenny 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 Sonora Blenny is a resident of Mexican waters of the Pacific but has a limited distribution being found only in the western and north eastern Sea of Cortez. They are one of the most common shallow water blennies in the northern Sea of Cortez.

The Sonora Blenny is mostly likely confused with the Glossy Blenny, Malacoctenus zonifer (front of dorsal fin light in color), the Mexican Blenny, Malacoctenus mexicanus (tan background color), the Redside Blenny, Malacoctenus hubbsi (males with lighter colored wide stripe below the dorsal fin; females caudal fins are not spotted), and the Throatspotted Blenny, Malacoctenus tetranemus (head and body covered with numerous black spots).

From a conservation perspective the Sonora Blenny is currently considered to be of Least Concern with stable widely distributed populations. They are small in stature and of little interest to most.