Lancetail Goby, Ctenogobius sagittula
Lancetail Goby, Ctenogobius sagittula. Fish caught from a coastal stream in the greater Puerto Peñasco area, Puerto Peñasco, Sonora, November 2022. Length: 9.8 cm (3.9 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.
The Lancetail Goby, Ctenogobius sagittula, is a member of the Goby or Gobiidae Family, that is also known at the Longtail Goby and in Mexico as barba de chocle, chalaco and gobio aguzado. Globally, there are twenty-eight species in the genus Ctenogobius, seven of which are found in Mexican waters, five in the Atlantic and two in the Pacific Ocean.
The Lancetail Goby has an elongated compressed body. They are a light tan color with four dark brown blotches along the middle of the sides and a dark brown spot at the middle of the caudal fin base, a brown stripe on the cheek and a brown blotch just behind the center of the gill cover, and a dark blotch on the side of the nape above the pectoral fin base. The caudal and second dorsal fins have brown spots. They have a short depressed head which has a blunt snout, large eyes set toward the front and a large horizonal mouth with teeth set in rows on both jaws with 1 or 2 large canines found at the front of the lower jaw. The anal fin has 1 spine and 13 to 15 rays; the caudal fin is long and pointed; the first dorsal fin has 6 spines; the second dorsal fin has 1 spine and 12 to 15 rays; and, the pelvic fins are fused to form a disc. They have 3 or 4 gill rakers on the lower arch. They are covered with rough scales.
The Lancetail Goby is a demersal species that is found in tranquil brackish and marine waters over shallow sand and bottoms of bays and estuaries with mangroves at depths up to 5 m (16 feet). They have the ability to breath air and can survive out of water for prolonged periods of time. They reach a maximum of 20 cm (7.9 inches). They are an omnivore that sift through mud to extract food for consumption. Reproduction is oviparous. The Lancetail 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 Lancetail Goby is a resident of all Mexican waters of the Pacific Ocean.
The Lancetail Goby is most likely confused with the Mangrove Goby, Ctenogobius manglicola (black spot which has an orange margin at the rear of the dorsal fin) an the Palmtail Goby, Gobionellus microdon (black oblique saddles at the top of the back).
From a conservation perspective the Lancetail Goby is currently considered to be of Least Concern with stable, widely distributed populations. They are very small in stature and of limited interest to most. Their long-term viability is threatened by the destruction of mangrove habitat by human coastal development.