Pilotfish, Naucrates ductor

Pilotfish, Naucrates ductor. Fish caught from coastal waters within Bahia Solano, Colombia, June 2019. Length: 13 cm (5.1 inches). Catch, photograph and identification courtesy of Chris Wheaton, Fullerton, California.

Pilotfish, Naucrates ductor. Fish provided by the commercial fishermen of the greater Los Cabos area, Baja California Sur, July 2009. Length: 21 cm (8.3 inches).

The Pilotfish, Naucrates ductor, is a member of the Jack or Carangidae Family, and is known in Mexico as pez piloto. There is only one member of the Naucrates Genus, this species which is found in Mexican waters of both the Atlantic and the Pacific Oceans. In Greek Mythology, they are known to follow ships for large distances with the ability to lead sharks to food and ancient mariners, whales, and swimmers to safety, giving rise to their common name. There are also reports that when “their” shark is caught they will follow that ship for up to six weeks.

The Pilotfish have elongated fusiform bodies that are wide in the middle and taper at both ends and have a depth that is 27% to 31% of standard length. They are silvery dark blue in color with a lighter belly and have 6 or 7 black bars on their sides. Their caudal fin is either black with white lobe tips or black with white lobe tips and two white stripes. Their mouth extends to under the front edge of the eyes. Their anal fin has two standalone spines followed by 1 spine and 15 to 17 rays; their caudal fin has a slender base with a well developed keel with notches above and below and is deeply forked; their first dorsal fin has 4 or 5 small free spines; their second dorsal fin has 1 spine and 25 to 29 rays; and, their pectoral fins are short. Their anal fin base is much shorter than their dorsal fin base. They do not have finlets or scutes.

The Pilotfish are a pelagic oceanic species found from the surface to depths up to 151 m (495 feet). They reach a maximum of 70 cm (2 feet 4 inches) in length. They usually accompany large fish, such as rays and sharks, as-well-as turtles. Juveniles are found in floating weeds or within schools of jellyfish. They are always found accompanying the Oceanic Whitetip Shark, Carcharhinus longimanus. Their relationship with sharks is a mutually beneficial one with them gaining protection from predators and sharks gaining freedom from parasites. They consume parasites attached to their larger traveling companions and leftovers of fish consumed by the larger species. The Pilotfish  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 Pilotfish is a wide-ranging circumglobal species found on the west coast of the Americas from British Columbia to Chile. In Mexican waters they are found in all waters of the Atlantic and the Pacific Oceans with the exception that they are absent from of the northern third of the Sea of Cortez.

The Pilotfish cannot be confused with any other species, due to its body shape and the pattern of bars on its sides.

From a conservation perspective the Pilotfish is currently considered to be of Least Concern with stable, widely distributed populations. In Mexico they are generally too small and too difficult to catch to be of interest to most. In other parts of the world however they are caught as a by-catch of other fisheries via dip nets, gill nets, hook and line, pelagic trawls. They are also a target of recreational anglers. They are considered to be a quality food fish.