Rough Searobin, Prionotus ruscarius
The Rough Searobin, Prionotus ruscarius, whose common Spanish name is vaca rasposa, is a species in the Searobin or Triglidae Family, known collectively as rubios and vacas in Mexico. Globally, there are twenty-three species in the genus Prionotus, fifteen of which are found in Mexican waters, ten in the Atlantic and five in the Pacific.
The Rough Searobins have rectangular block-like bodies 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 two 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 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 anal, dorsal, and pelvic fins are transparent. Their caudal fin is slightly concave with one or two 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, and 10 to 12 rays. Their pectoral fins are short and dark in color, and have 13 rays of which three are free and shorter than the fin. Their body is covered with very rough scales.
The Rough Searobins are found over and within sandy and muddy bottoms at depths up to 350 feet. They reach a maximum length of 41 cm (16 inches), 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.
In Mexican waters the Rough Searobin are found from Magdalena Bay 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).
Due to their bony structure and rarity, the Rough Searobins are of limited interest to most. They are a frequent by-catch of deepwater shrimp trawlers around the tip of Baja.