Bluestriped Chub, Kyphosus ocyurus
The Bluestriped Chub, Kyphosus ocyurus, whose common Spanish name is chopa salema, is a species in the Sea Chub or Kyphosidae Family, known collectively as chopas in Mexico. Globally, there are fourteen species in the genus Kyphosus, seven of which are found in Mexican waters, three in the Atlantic and four in the Pacific.
The Bluestriped Chubs have elongated oval compressed bodies that have a depth that is 33 to 37% of standard length. They are silvery-olive dorsally transitioning to white ventrally. They have a broad bright blue midlateral stripe and a yellow stripe immediately below. Their caudal fin is yellow. There is a blue band along the base of their dorsal fin. They have a small pointed head with convex upper and lower profiles. They have a short snout and a very short horizontal mouth that opens at the front with small incisiform flattened teeth. Their anal fin has 3 spines and 14 rays, which are low and of uniform height, their caudal fin is forked, their dorsal fin is continuous with 11 spines folding down into a scaly grove and 13 rays, which are low, and their pectoral and pelvic fins are relatively short. Their body is covered with small, thick, and rough scales.
The Bluestriped Chubs are schooling fish found near floating logs far out at sea from the surface to depths up to 100 feet. They reach a maximum length of 70 cm (28 inches). They are omnivores feeding on benthic algae, plankton, and small invertebrates.
In Mexican waters the Bluestriped Chubs are found along the entire west coast of Baja, in the southern extreme of the Sea of Cortez (documented by a fish that I caught), and along the coast of the mainland from Mazatlán to Guatemala. They are a far-ranging pelagic species that are also found in the waters of Hawaii, the Marquesas Islands of Polynesia, and Tahiti.
The Bluestriped Chub is most likely confused with the Rainbow Runner, Elagatis bipinnulata (more aerodynamic; body width 20 to 24% of standard length).
The Bluestriped Chub are an obscure species virtually unknown to local fishermen.
Bluestriped Chub, Sectator ocyurus. Fish caught from coastal waters off Mazatlan, Sinaloa, October 2016. Length: 43 cm (17 inches). Catch and photo courtesy of George Brinkman, Guelph, Ontario, Canada.