Broadstripe Goby, Elacatinus prochilos
Broadstripe Goby, Elacatinus prochilos. Underwater photographs taken in coastal waters of Yal-Ku, Quintana Roo, April 2016. Photographs courtesy of Juan Rojo, Akumal.
The Broadstripe Goby, Elacatinus prochilos, is a member of the Goby or Gobiidae Family. There are twenty-four global members of the Elacatinus Genus of which ten are found in Mexican waters of the Atlantic Ocean. They are also known as the White Stripe Goby and in Mexico as Gobio Bordeado. They are scientifically interesting due to having two behavioral ecotypes – the first provides cleaning services to other fishes within corals as male-female pairs; the second by performing spatial tasks within barrel sponges demonstrating an ability to understand, reason, and remember relationships between objects and occurs in large groups.
The Broadstripe Goby has an elongated body with a compressed head that has a rounded profile and large eyes that protrude from the top of the head that has a short snout with a subterminal mouth. They are a black dorsally and pale gray ventrally sprinkled with melanophores. They have a prominent pale dark blue horizontal eye-width band that is boarded by white above that extends on to the snout forming a “V”, and through the eye to the caudal fin. The fins are also covered with melanophores. Their anal fin has 1 spine and 11 rays; their caudal fin is elongated and rounded; their first dorsal fin has 7 spines, and the second dorsal fin has 1 spine and 11 or 12 rays; their pectoral fins have 17 to 19 rays; and their pelvic fins have 1 spine and 5 rays are fused to form a sucking disk. They have 8 gill rakers. They do not have scales and they do not have a lateral line.
The Broadstripe Goby is a non-migratory coral-dwelling cleaner goby that is found in groups near coral heads and sponges in coastal areas at depths up to 55 m (180 feet). They live in a symbiotic relationship with the Boulder Star Coral, Montastrea annularis. They reach a maximum of 4.0 cm (1.6 inches) in length. They consume Gnathiid isopod larvae and caligid copepods in addition to fish scales, mucous, coral polyps and sponges. In turn they are prey upon by groupers, sandperches and various wrasses. Reproduction is dioecism within individual males and females and occurs within small holes with the reef involving monogamous mating with external fertilization where parental care is provided. The sexes can be distinguished by the shape of the males urogenital papilla. Their larvae are very localized limiting the reseeding of depleted subpopulations.
The Broadstripe Goby is a resident of Mexican waters of the Atlantic Ocean but has a limited distribution being found with two distinct populations – the first is restricted to the Veracruz Reef System and the second from the east coast of the Yucatán Peninsula within the coastal waters along the east coast of Quintana Roo, south to Belize.
The Broadstripe Goby is mostly likely confused with the Belize or Caribbean Neon Goby, Elacatinus lobeli (lacks the blue band extending into a “V”).
From a conservation perspective the Broadstripe Goby is currently considered to be VULNERABLE, with their long term viability being threatened by the loss of coral reef habitat, and specifically the Boulder Star Coral, which is attributed to coastal development and human population. They are known to be prey to the newly introduced highly invasive Common Lionfish, Pterois miles and the Red Lionfish, Pterois volitans. They are considered to be are small in stature and are utilized by the aquarium trade at a nominal level. They have been raised in captivity.
Mouth with a broad band of teeth at the rear on the lower jaw narrowing to a single series on the sides with two or three enlarged canines.
Dark gray upper head and body, a wide dark stipe under the white stripe.