Shortjaw Mudsucker

Shortjaw Mudsucker, Gillichthys seta

Shortjaw Mudsucker, Gillichthys seta, Juvenile. Fish caught from a tidal pool of Puerto Peñasco, Sonora, November 2020. Length: 5.4 cm (2.,0 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Shortjaw Mudsucker, Gillichthys seta. Fish caught from coastal tidal pools on Los Conchas Beach, Puerto Peñasco, Sonora, April 2021. Length: 6.0 cm (2.4 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.

Shortjaw Mudsucker, Gillichthys seta. Fish caught from coastal tidal pools on Los Conchas Beach, Puerto Peñasco, Sonora, November 2022. Length: 6.0 cm (2.4 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.

The Shortjaw Mudsucker, Gillichthys seta, is a member of the Goby or Gobiidae Family, that is also known simply as the Mudsucker and is known in Mexico as chupalodo chico. Globally, there are three species in the genus Gillichthys, and all three are found in Mexican waters of the Pacific Ocean.

The Shortjaw Mudsucker has a moderately elongated compressed body. Their body is pigmented overall with light brown sides with alternating dark brown and pale yellow blotches, six diffuse black saddles on the back, and a yellowish belly.  Their head is broad and large with a pointed depressed snout with small eyes that are set far apart and a slightly upturned mouth with very long jaws equipped with small conical teeth set in four or five rows on each jaw.  Their anal fin has 1 spine and 8 or 9 rays with a short base; their caudal fin is rounded; their first dorsal fin has 4 to 8 spines and is low and rounded; their first dorsal fin is small with 4 to 8 spines and low and rounded; their second dorsal fin has 1 spine and 10 to 12 rays; their pectoral fins and broad, rounded and the first two rays are small and free from the fin; and, their pelvic fins are fused into a sucking disc. They are covered with small smooth scales. They are covered with thick mucous.

The Shortjaw Mudsucker is a small shallow-water species that is found in rocky tidal pools with fine sand substrate at depths up to 2 m (7 feet) in the upper intertidal zone. They reach a maximum 6 cm (2.4 inches) in length. Reproduction is oviparous. The Shortjaw Mudsucker 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 Shortjaw Mudsucker is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found only in the northern half of the Sea of Cortez along the coasts of both Baja California and Sonora.

The Shortjaw Mudsucker is most likely confused with the Shadow Goby, Quietula y-cauda (large spots along the flank) and the Longjaw Mudsucker, Gillichthys mirabilis (large mouth; blue-black dorsally).

From a conservation perspective the Shortjaw Mudsucker is currently considered to be VULNERABLE which is attributed to its limited distribution range and significant changes within the coastal habitat in which they reside caused by human development. Efforts to introduce this species into the Salton Sea in 1951 failed.