Shadow Goby, Quietula y-cauda
Shadow Goby, Quietula y-cauda. Fish caught from within Mission Bay, San Diego, California, December 2022. Length: 4.8 cm (1.9 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
Shadow Goby, Quietula y-cauda. Fish caught from within Mission Bay, San Diego, California, January 2020. Length: 6.2 cm (2.4 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.
Shadow Goby, Quietula y-cauda. Fish caught from within Ventura Harbor, Ventura, California, July 2021. Length: 6.4 cm (2.5 inches). Catch, photograph and identification courtesy of Chris Moore, Peoria, Arizona.
The Shadow Goby, Quietula y-cauda, is a member of the Goby or Gobiidae Family, that is also known as the American Shadow Goby and in Mexico as the gobio sombreado. Globally, there are 2 species in the genus Quientula, both of which are found in Mexican waters of the Pacific Ocean.
The Shadow Goby has an elongated slender slightly compressed body with a large depressed head that has large eyes on top set close together, a large mouth that reaches to the operculum equipped with a single series of teeth on the lower jaw and the front half of the upper jaw. They vary in color being light to dark dorsally transitioning to paler ventrally. Their head and body are covered with dark specks and there is a row of dark spots along the mid-body. Males have a thick black stripe along the middle of the anal fin and a Y-shaped mark on the caudal peduncle. Their anal fin has 1 spine and 12 to 15 rays; their caudal fin is rounded; their first dorsal fin has 4 or 5 spines; their second dorsal fin has 1 spine and 13 to 15 rays; and their pectoral fins are long with 19 rays and reach past the end of the pelvic fins. They have 11 to 13 short blunt gill rakers. Their body is covered with small smooth scales.
The Shadow Goby is a demersal species that is found in the intertidal zone of mud flats of lagoon and river mouths at depths up to 6 m (20 feet). They are known to reside in shrimp and worm burrows. They reach a maximum length of 7.0 cm (2.8 inches). They are nighttime predators that retreat to their burrows during the day. They consume amphipods, crab larvae, hydrozoans and large quantities of polychaetes worms. In turn they are preyed upon by a wide variety of fishes and by octopuses. They are highly territorial driving off intruders. Reproduction is oviparous with each female depositing between 400 and 2,000 eggs more than once a year. The eggs are attached to the walls of the burrows which are then guarded by the males until they hatch. The Shadow Goby has a lifespan of up to 5 years.
The Shadow Goby is similar in in body shape and appearance to six additional Gobies and are found in the Sea of Cortez and adjacent waters, the Bright Goby, Ilypnus luculentus, the Cheekspot Goby, Ilypnus gilberti, the Guaymas Goby, Quietula guaymasiae, the Longjaw Mudsucker, Gillchthys mirabilis, the River Goby, Awaous banana, and the Shortjaw Mudsucker, Gillichthys seta, but all 6 lack the row of dark spots along the mid-body and the “y” at the base of the caudal peduncle.
The Shadow Goby is a resident of Mexican waters of the Pacific but has a limited range being found along the entire west coast of Baja and throughout the Sea of Cortez.
From a conservation perspective the Shadow Goby is currently considered to be of Least Concern with stable, widely distributed population. Regionally they have been adversely affected by coastal development and mangrove destruction.