Black Marlin, Istiompax indica
Black Marlin, Istiompax indica. Fish caught in coastal waters off Puerto Los Cabos, Baja California Sur, July 2000. Weight: 326 kg (717 lbs). Caught courtesy of Ron Hutchin, Photograph courtesy Eric Brictson, Gordo Banks Pangas, La Playita, Baja California Sur.
The Black Marlin, Istiompax indica, is a member of the the Billfish or Istiophoridae Family, and is known in Mexico as marlina negro. They are are the largest member of the family. This species changes color to white upon death giving rise to the alternative common and confusing name “White Marlin”. Note: this fish has very recently been reclassified as Istiompax indica genus having formerly been Makaira indica. It is the only species in the genus Istiompax, and is a resident in Mexican waters of the Pacific Ocean.
The Black Marlin has a long robust but not strongly compressed body. They are dark blue dorsally and silver ventrally with a limited number of vertical stripes or spots on their sides. Their first dorsal fin is black to dark blue and their other fins are brown. Their head has a long stout upper bill with a rounded cross section and relatively small eyes. Their mouth is equipped with small rasp-like teeth on both jaws. They do not have gill rakers. Their first anal fin has 10 to 14 rays; their second anal fin has 6 or 7 rays; their caudal fin is deeply forked; their first dorsal fin has 34 to 43 rays and with a long base and is low, being less than half the body length in height, and is rounded; the second dorsal fin has 5 to 7 rays and is located before the second anal fin; their pectoral fins do not fold against the body, which is unique to this species; and their pelvic fins are shorter than the pectoral fins. They have 2 keels on the side of their tail base. Their body is covered with thick elongated bony scales. Their lateral line is visible and curves over the pectoral fins and straight toward the tail base.
The Black Marlin is an epipelagic and oceanic species usually found in surface waters above the thermocline and often near shore. They have also been found at depths up to 300 m (1,000 feet) that has been determined by satellite tagging. Scientifically they have been extensively studied. They are a seasonal migratory species traveling in schools and are only found in waters with temperatures between 21oC (70oF) to 28oC (84oF). Males and females are indistinguishable by external features however, the species is dimorphic. They reach a maximum of 4.48 m (14 feet 8 inches) in length. All trophy catches are females, as females are significantly larger than males; males do not exceed 136 kg (300 lbs). As of January 1, 2023, the International Game Fish Association world record stood at 4.42 m (14 feet 6 inches) and 707.6 kg (1,560 lbs) with the fish caught in coastal waters off Peru in August 1953. They normally range in size from 68 kg (150 lbs) to 136 kg (300 lbs). Being carnivorous and non-selective feeders, they compete for the same food as other billfish, dorados, large sharks, swordfish, large tuna, and wahoo. They stun their prey with their elongated bill and then circle back to collect them. Once mature they are generally free from predation by other fish. Reproduction occurs via pelagic eggs with each female capable of releasing up to 40,000,000 eggs per annum. Juveniles are fast growing and seldom seen by humans.
The Black Marlin is a resident of all Mexican waters of the Pacific Ocean with the exception that they are absent from the extreme northern Sea of Cortez.
The Black Marlin is most likely confused with the Blue Marlin, Makaira nigricans (blue coloration; dorsal height less than body depth; gradated first dorsal fin).
The Black Marlin is a highly prized big game species and one of the true “BIG FISH” in the ocean. They are known for their phenomenal acrobatic aerial displays when hooked, their size and strong stamina. Commercially they are pursued by longlining, harpooning, trolled nets, and set nets with global annual catches on the order of 3,000 tons. The majority are caught are a by-catch of commercial longlines targeting tuna who use as many as 2,000 hooks in one string. The quality of the flesh is considered “good” and they are marketed fresh and frozen and utilized primarily for sashimi with a large market in Japan. From a conservation perspective that are currently considered to be VULNERABLE, however, their global population and related trends has not well documented. Declines in their global populations estimated to be occurring at a rate of about 5% per year. Globally, they are poorly managed with a very limited and declining number of conservation measures in place. However, they are protected in Mexico, where they cannot be taken by commercial fishermen within fifty miles of the coast.
A word of caution: these fish are ginormous wild animals and their spears are very dangerous!