California Needlefish, Strongylura exilis
The California Needlefish, Strongylura exilis, whose common Spanish name is agujón californiano, is a member of the Needlefish or Belonidae Family, known collectively as agujones in Mexico. Globally, there are 14 species in the genus Strongylura, of which four are found in Mexican waters, three in the Atlantic and one in the Pacific.
The California Needlefish have very elongated rounded bodies with extremely elongated jaws, a relatively short beak, and numerous needle-like teeth. They are blue-green dorsally and transition to silver ventrally. They have a dark blue stripe mid-flank and dark pigmentation at the junction of their cheek and gill cover that extends down to their eyes. Their eyes and fins are yellowish. This countershading provides camouflage to avoid predation. Their fins have no spines and they have no gill rakers. The front lobe of their anal fin is larger than the dorsal fin and their anal and dorsal fins have low lobes at the rear. Their anal fin has 16 to 19 rays; their caudal fin is slightly concave; their dorsal fin has 13 to 17 rays; and their pectoral fins are small. Their body is covered with small scales.
The California Needlefish are a coastal pelagic species found in lagoon areas with mangroves, in bays, and in harbors at depths up to 330 feet. They are known to enter freshwater systems. They reach a maximum length of 91 cm (3 feet 0 inches). Adults form small schools and are voracious predators feeding on pelagic crustaceans and small fish. Reproduction is oviparous with females laying large spherical eggs in shallow water habitats which attach themselves to floating vegetation via long filamentous tendrils before being fertilized by males. The larvae are pelagic.
In Mexican waters the California Needlefish are common and found in all waters of the Pacific.
The California Needlefish is easy to recognize and cannot be confused with any other needlefish from the Pacific.
From a conservation perspective, the California Needlefish are currently considered of Least Concern, having wide distribution, stable populations, and no fishing pressure. They are not commercially important and are caught by recreational anglers as a by-catch. In some parts of their range they are caught commercially using artificial lights and are marketed fresh. They are considered a poor food fish due to their overabundant bones.
California Needlefish, Strongylura exilis. Fish caught from within Magdalena Bay, Baja California, May 2017. Length: 54 cm (21 inches). Catch and photo courtesy of Jimmy Camacho, Puerto Adolfo Lopez Mateos, Baja California Sur.