California Halfbeak, Hyporhamphus rosae

California Halfbeak, Hyporhamphus rosae. Fish caught from coastal waters off Agua Verde, Baja California Sur, March 2020. Catch and photograph courtesy of Barry Mastro, Escondido, California.

The California Halfbeak, Hyporhamphus rosae, is a member of the Halfbeak or Hemiramphidae Family, and is known in Mexico as pajarito californiano. Globally, there are thirty-six species in the genus Hyporhamphus, of which six are found in Mexican waters, three in the Atlantic and three in the Pacific Ocean.

The California Halfbeak has and elongated cylindrical slender body. They have a silvery translucent green appearance dorsally and transition to white ventrally. They have a silver stripe on the flank. Their lower jaw is dark red and their fins are transparent.Their lower jaw extends into a greatly prolonged beak and their upper jaw is short and triangular. They do not have teeth. Their anal fin has 14 to 16 rays and is at the rear of the body and originates in the middle of the dorsal fin; their caudal fin is concave with the lower lobe being larger than the upper lobe; their dorsal fin has 13 to 15 rays and is at the rear of the body and originates behind the anus; their pectoral fins are high on the sides; and, their pelvic fins are on the abdomen well back on the body with their origin being closer to the caudal fin than the gill cover. They have 28 to 36 gill rakers. They are covered with large smooth scales. Their lateral line is low on the body.

The California Halfbeak is a coastal pelagic schooling species that is found along the coast, in coastal bays and adjacent freshwater on the surface to depths of 2 m (6 feet). They reach a maximum of 22 cm (8.7 inches) in length. They feed on small fish and plankton. In turn they are preyed upon by birds, dolphins, dorado, marlins, porpoises, squids, and tuna. Reproduction is oviparous with females releasing large eggs containing a sticky substance that allows the eggs to attach to floating debris. Their larvae is planktonic. The California Halfbeak The California Grunion 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 California Halfbeak is a resident of all Mexican waters of the Pacific Ocean.

The California Halfbeak, Hyporhamphus rosae, can be easily confused with the Choelo Halfbeak, Hyporhamphus gilli (37-50 gill rakers), the Longfin Halfbeak, Hemiramphus saltator (25 to 32 gill rakers) and the Pacific Silverside Halfbeak, Hemiramphus naos (29-39 gill rakers) and none of these have an extended dark red lower bill and an anal fin that is set behind the dorsal fin origin.

From a conservation perspective the California Halfbeak is currently considered to be Data Deficient. Their long term viability is threatened by coastal development and pollution. They are uncommon and of limited interest to most.