Mirrorwing Flyingfish, Hirundichthys speculiger
The Mirrorwing Flyingfish, Hirundichthys speculiger, whose Spanish common name is volador espejo, is a species in the Exocoetidae Family, known collectively as voladores in Mexico. Globally, there are only seven species in the genus Hirundichthys, five of which are found in Mexican waters, one in the Atlantic, one in the Pacific and three, including this species, found in both oceans.
The Mirrorwing Flyingfish have elongated cylindrical bodies. They are iridescent dark blue dorsally and silvery ventrally. Their anal and dorsal fins are gray, their pectoral fins are dark with a broad transverse clear bar from the base to the middle of the fin and a broad clear margin, and their pelvic fins are transparent. Juveniles have pectoral and pelvic fins that are mottled with dark spots and bars and do not have barbels. They have a short head, a short blunt snout, and a small mouth with conspicuous conical teeth on the sides of the jaws which are both of equal length. Their anal fin originates slightly behind the dorsal fin origin and has 11 to 13 rays; their caudal fin is deeply forked with the lower lobe being significantly larger than the upper lobe; their dorsal fin has 10 to 13 rays; their pectoral fins are set high on the body and are extremely long reaching beyond the anal fin origin; and their pelvic fins are long, reach past the anal fin origin, and are nearer the gill cover than the caudal fin origin. Their lateral line is low on the body. They are covered with large smooth scales.
The Mirrorwing Flyingfish are an oceanic pelagic species found on the surface to depths of 100 feet. They reach a maximum length of 30 cm (12 inches). They feed on planktonic organisms and small fish. In turn they are preyed upon by birds, dolphins, dorado, marlins, porpoises, squid, and tuna. They have large pectoral fins and are capable of leaping and gliding considerable distances above the ocean surface. Reproduction is oviparous with the release of large sticky filaments that attach to floating or benthic weeds.
In Mexican waters the Mirrorwing Flyingfish are found in all waters of the Atlantic and the Pacific with the exception that they are absent from the Sea of Cortez and along the entire west coast of Baja. The fish pictured below was collected at 44oN, which is 4oN of the known range for this species in the Atlantic (40oS to 40oN latitude).
The Mirrorwing Flyingfish is fairly similar to the Fourwing Flyingfish, Hirundichthys affinis from the Atlantic (narrow white pectoral fin margin) and the Whitetip Flyingfish, Cheilopogon xenopterus from the Pacific (dorsal margin with large black blotch; black caudal fin with clear tip).
The Mirrorwing Flyingfish are seldom seen by humans. Due to their rarity, they are of limited value and interest to most.
Mirrorwing Flyingfish, Hirundichthys speculiger. Fish collected off the Martinque Beach Provincial Park, East Petpeswick, Nova Scotia, August 2015. Length: 17.2 cm (6.8 inches). Photos provided by Ashley Bingham, We Love Nova Scotia, Facebook.