Cheekspot Goby, Ilypnus gilberti
Cheekspot Goby, Ilypnus gilberti. Fish caught from within Mission Bay, San Diego, California, February 2020. Length: 6.2 cm (2.4 inches). Catch, photographs and identification courtesy of Ben Cantrell, San Diego, California.
Cheekspot Goby, Ilypnus gilberti. Fish caught from within the Ventura Harbor, Ventura, California, March 2021. Length: 6.2 cm (2.4 inches). Catch, photographs and identification courtesy of Chris Moore, Peoria, Arizona.
Cheekspot Goby, Ilypnus gilberti. Underwater photograph taken with Mission Bay, San Diego, California, October 2019. Photograph and identification courtesy of Ben Cantrell, San Diego, California.
The Cheekspot Goby, Ilypnus gilberti, is a member of the Goby or Gobiidae Family, that is known in Mexico as the gobio mejilla manchada. Globally, there are two species in the genus Ilypnus, both of which are found in Mexican waters of the Pacific Ocean.
The Cheekspot Goby has an elongated slender compressed body with an oblique mouth that reaches the middle of the eyes. They are light tan in color. Their head has a black stripe on the underside, bright white patches at the upper corner of the mouth and tip of the chin and an iridescent blue-black blotch on the gill cover (for which they are named). The sides of their body are covered with fine dark spots. Their anal fin has a central broad stripe; the caudal fin is rust colored above and below with a gray center and white margin with 5 wavy bars in the center; the dorsal fins are red-brown with a white margin and each ray has black dots that form stripes; and, their pectoral fins have bright white margins. Their anal fin has 1 spine and 14 to 16 rays; their first dorsal fin has 4 to 6 spines; their second dorsal fin has 1 spine and 15 to 17 rays; and, their pelvic fins form a cup that is found under the base of the pectoral fins. Their body is covered with small smooth scales.
The Cheekspot Goby is a demersal species that is found in the intertidal zone over sand substrate in bays and estuaries at depths up to 24 m (79 feet) with mature fish residing ins self-dug burrows. They reach a maximum of 6.8 cm (2.7 inches) in length with females being larger than males. They are daytime predators that retreat to their burrows at night. 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 herons. They are highly territorial driving off intruders. Reproduction is oviparous with each female depositing between 350 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 Cheekspot Goby have life spans of five years. The Checkspot Goby 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 Cheekspot Goby is similar in in body shape and appearance to four additional Gobies and are found in the Sea of Cortez and adjacent waters, the Shadow Goby, Quietula y-cauda, the Bright Goby, Ilypnus luculentus, the Guaymas Goby, Quietula guaymasiae and the River Goby, Awaous banana, but all four lack the dark spot on the gill cover and the subtle black lines on their sides.
The Cheekspot Goby is a resident of Mexican waters of the Pacific but has a limited distribution being found from Magdalena Bay, Baja California Sur, northward along the central and northwest coasts of Baja and throughout the Sea of Cortez south to La Paz, Baja California Sur.
From a conservation perspective the Cheekspot 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.