Pacific Silverstripe Halfbeak

Pacific Silverstripe Halfbeak, Hyporhamphus naos

The Pacific Silverstripe Halfbeak, Hyporhamphus naos, whose Spanish common name is pajarito blanco del Pacifico is a species in the Halfbeak or Hemiramphidae Family, known collectively as pajaritos in Mexico. This fish is also known as the Naos Halfbeak. Globally, there are thirty-six species in the genus Hyporhamphus, six of which are found in Mexican waters, three in the Atlantic and three in the Pacific.

The Pacific Silverstripe Halfbeaks have elongated cylindrical slender bodies. They have a silvery appearance with a translucent back, a silver stripe along their flank with a dark border that widens toward the rear, and a white belly. Their snout and beak are black with a red tip. The fins are transparent to dusky. Their lower jaw extends into a prolonged beak and their upper jaw is short and triangular. They have no teeth. Their anal fin has 15 to 17 rays and originates directly under the dorsal fin; their caudal fin is moderately forked with the lower lobe being larger than the upper lobe; their dorsal fin has 14 to 16 rays and originates behind the anus; their pectoral fins are short, high on the sides, and do not reach the nostrils when folded forward; and their pelvic fins are on the abdomen well back on the body with the origin being about equal distance between the pupil and the caudal fin base. They have 29 to 39 gill rakers. Their anal and dorsal fins are well back on the body with bases opposite each other. Their lateral line is low on the body and they are covered with large smooth scales.

The Pacific Silverstripe Halfbeaks are a pelagic species normally found in coastal waters on the surface to depths of 100 feet. They reach a maximum length of 21 cm (8.3 inches). They feed on planktonic organisms and small fish. 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. Although fairly common, they are a poorly studied species and very little is known about their behavioral patterns

In Mexican waters of the Pacific the Pacific Silverside Halfbeaks have a limited range being found from Guerrero Negro southward along the central and southwest coasts of Baja, in the southern half of the Sea of Cortez, and along the coast of the mainland south to Guatemala.

The Pacific Silverstripe Halfbeak can be easily confused with the California Halfbeak, Hyporhamphus rosae (caudal fin modestly forked), the Choelo Halfbeak, Hyporhamphus gilli (37 to 50 gill rakers), and the Longfin Halfbeak, Hemiramphus saltator (25 to 32 gill rakers).

The Pacific Silverstripe Halfbeak are unable to survive a panga bait tank making them poor live bait and therefore of limited value to most.

Pacific Silverstripe Halfbeak, Hyporhamphus naos. Fish provided by the commercial bait salesmen of from Puerto Los Cabos, Baja California Sur, September, 2007. Length: 18 cm (7.1 inches). Fish identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.