Sonora Clingfish, Tomicodon humerialis

Sonora Clingfish, Tomicodon humerialis. Fish caught from coastal tidal pools on Los Conchas Beach, Puerto Peñasco, Sonora, November 2022. Length: 5.1 cm (2.0 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Sonora Clingfish, Tomicodon humerialis, Dark Morph. Fish caught from coastal tidal pools on Los Conchas Beach, Puerto Peñasco, Sonora, November 2022. Length: 5.2 cm (2.0 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

The Sonora Clingfish, Tomicodon humerialis, is member of the Gobiesocidae Family of Clingfishes, and is known in Mexico as chupapiedras de Sonora and pejesapo de Sonora. Globally, there are twenty-two species in the genus Tomicodon, of which six are found in Mexican waters, all in the Pacific Ocean.

The Sonora Clingfish has an elongated “tadpole” like body that is relatively slender compared to other Clingfish. They are a greenish brown color with narrow white bars on the sides and across the back with scattered dark spots on the back and a large dark blotch above each pectoral fin base. The head is slender with large prominent eyes, a blund snout, and a mid-sized terminal mouth that opens in the front that is equiped with 5 to 7 pairs of incisors at the front and 2 to 4 well developed canines at the front and 3 or 4 canines on the lower jaws. The anus is closer to the anal fin origin than to the rear margin of the disc. They have 6 or 7 anal fin rays, 8 or 9 dorsal fin rays, and 17 to 19 pectoral fin rays. Their skin is smooth and is without scales.

The Sonora Clingfish is benthic and found within the intertidal rocky zone in shallow waters at depths up to 5 m (17 feet). They reach a maximum of 10 cm (3.9 inches) in length. They feed primarily on barnacles, limpets and small crustaceans. They can survive in environments with elevated temperatures and can breath air and able to survive for two days out of water. The Sonora Clingfish 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 Clingfish is an endemic species to Mexico being found throughout the western and northeastern portions of the Sea of Cortez.

The Sonora Clingfish is similar in stature and appearance to the Cortez Clingfish, Tomicodon boehlkei, the Rosy Clingfish, Tomicodon eos, and the Zebra Clingfish, Tomicodon zebra, but all three have wide dark bars dorsally.

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