Goldline Blenny, Malacoctenus aurolineatus
Goldline Blenny, Malacoctenus aurolineatus. Underwater photographs taken in coastal waters of Yal-Ku, Quintana Roo, April 2016. Photographs and identifications courtesy of Juan Rojo, Akumal.
The Goldline Blenny, Malacoctenus aurolineatus, is a member of the Labrisomid Blenny or Labrisomidae Family, and is known in Mexico as sapito de monture and trambollo lineado. Globally, there are twenty-three species in the Malacoctenus Genus, of which thirteen are found in Mexican waters, five in the Atlantic and eight in the Pacific Ocean.
The Goldline Blenny has an elongated body with a uniform depth throughout that tapers gradually at the rear into the tail. The body has three close-set thick bars under the first dorsal fin; the first two are connected and form an “H”; they are followed by a whitish bar and then a fourth dark bar; the last is remote from the first three. At the rear there are three or four indistinct brown bars. They have a brown head dorsally that transitions to white ventrally with five wide bars on the lower cheeks. They have thin gold stripes along the lower body for which they are named. The head is slender with a pointed snout with a simple cirrus over each nostril, 9 to 13 cirri on each nape and a forked cirrus over each eye. Their mouth is large and opens in the front and is equipped with a row of large teeth on the upper jaws. Their anal fin has 2 spines and 19 or 20 rays; their first dorsal fin has 18 to 21 spines; their second dorsal fin has 10 to 12 rays; their pectoral fins have 14 rays; and their pelvic fins have 1 spine and 3 rays that are inserted before the pectoral fins. Their lateral line extends to mid-body and they are covered with smooth scales.
The Goldline Blenny is a shallow water benthic coastal species found within coral and rocky reefs at depths up to 12 m (40 feet). They reach a maximum length of 7.5 cm (3.0 inches). They are diurnal highly territorial predators that feed on amphipods and copepods. Reproduction is oviparous with females depositing eggs in protected areas. They are found in close proximity to the Rock Boring Sea Urchin, Echinometra lucunter. The Goldline Blenny is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, diet, growth, habitat, longevity, movement patterns, and reproduction.
The Goldline Blenny is a resident of Mexican waters of the Atlantic Ocean but has a limited distribution being found from the Bay of Campeche and is coastal waters of the Yucatán Peninsula south to Belize.
The Goldline Blenny can be confused with the Barfin Blenny, Malacoctenus versicolor (5 wide dark bars on the sides), the Diamond Blenny, Malacoctenus boehlkei (large yellow-ringed ocellus at the front of the dorsal fin), the Dusky Blenny, Malacoctenus gilli (dark colored without facial bars), the Imitator Blenny, Malacoctenus erdmani (dark saddles at rear of dorsal fin), the Rosy Blenny, Malacoctenus macropus (dark saddles at rear of dorsal fin), and the Saddled Blenny, Malacoctenus triangulatus (four triangular saddles on the back).
From a conservation perspective the Goldline Blenny 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 coral reef degradation related to coastal development and pollution.