Rough Searobin, Prionotus ruscarius

Rough Searobin, Prionotus ruscarius. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, July 2008. Length: 41 cm (16 inches).

The Rough Searobin, Prionotus ruscarius, is a member of the Searobin or Triglidae Family, and is known in Mexico as vaca rasposa. Globally, there are twenty-three species in the genus Prionotus, of which fifteen are found in Mexican waters, ten in the Atlantic and five in the Pacific Ocean.

The Rough Searobin has a rectangular block-like body that are olive brown in color with white undersides. Their large square bony head features large eyes and is covered with many ridges and spines. They have 2 faint dark bars on their sides, the first under their first dorsal fin and the second under the rear of their second dorsal fin. Their anal, dorsal, and pelvic fins are transparent. Their head, which is as wide as it is deep, has a broad rounded snout and a wide concave gap between the eyes and slightly projecting snout plates. Their anal fin has 10 or 11 rays; their caudal fin is slightly concave with 1 or 2 vertical rows of dusky spots and white rays with black membranes; their first dorsal fin has 10 spines, the first two being of equal length; their second dorsal fin has 10 to 12 rays; and, their pectoral fins are short and dark in color, and have 13 rays of which 3 are free and shorter than the fin. Their body is covered with very rough scales.

The Rough Searobin is found over and within sandy and muddy bottoms at depths up to 107 m (350 feet). They reach a maximum of 41 cm (16 inches) in length, as established by a fish in my possession. They are more active and feed at night; during the day they are found submerged in sand. The Rough Searobin 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 Rough Searobin is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from Magdalena Bay, Baja California Sur southward along the southwest coast of Baja, in the southern half of the Sea of Cortez, and along the coastal mainland south to Guatemala.

The Rough Searobin is most likely confused with the Bristly Searobin, Prionotus horrens (deep head with large eyes; anal fin with nine rays).

From a conservation perspective the Rough Searobin is currently considered to be of Least Concern with stable, widely distributed populations. Due to their bony structure and rarity, they are of limited interest to most. They are a frequent by-catch of deepwater shrimp trawlers around the tip of Baja.