Network Sole, Achirus scutum

Network Sole, Achirus scutum. Underwater photograph taken in Zihuantanejo Bay, Guerrero, February 2023. Photograph courtesy of Ron Woheau, Zihuantanejo.

The Network Sole, Achirus scutum, is a member of the American Sole or Achiridae Family, and is known in Mexico as comal. Globally, there are eight species in the genus Achirus, of which four are found in Mexican waters, one in the Atlantic and three in the Pacific Ocean.

The Network Sole has a round, flattened body, with a width that is of 78% to 82% of standard length. They have a uniform dark brown coloration with 20 tan or whitish bars that are wavy and join adjacent bars to create a maze-like pattern. Their pelvic and pectoral fins have pale wavy bands. Their head has a rounded snout with a small mouth and small eyes that are set close together on their right side, with the top eye being slightly behind the bottom eye. Their anal fin has 42 to 44 rays and is fused to their pelvic fins; their dorsal fin originates above the eyes and has 53 to 59 rays; and, their pectoral fins are small and have 3 or 4 rays. Their body is covered with rough scales; the scales on their dorsal side have black hair-like filaments. Their lateral line is prominent and straight running from the head to the caudal fin.

The Network Sole is a demersal species that is found over and within soft bottoms in bays, estuaries, and adjacent freshwater streams at depths up to 45 m (150 feet). They reach a maximum length of 19 cm (7.5 inches). They consume small crustaceans, small fishes, polychaetes worms and detritus. Their eggs and larvae are pelagic. Although widespread and common in some areas the Network Sole 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 Network Sole is found from Mazatlán south along the west coast of the mainland south to Guatemala in the Pacific Ocean.

The Network Sole, due to its round profile and unique markings is a straightforward identification that cannot be confused with any other fish.

From a conservation perspective, the Network Sole is currently considered to be of Least Concern. They are small in stature, and although common they are seldom seen by humans, and are of limited interest to most.