Frigate Mackerel, Auxis thazard

Frigate Mackerel, Auxis thazard. Fish caught from coastal waters off Puerto Peñasco, Sonora, November 2022. Length: 32 cm (13 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Frigate Mackerel, Auxis thazard. Fish caught off Point Palmilla, Baja California Sur, September 2015. Length: 36 cm (14 inches). A large fish for those caught in the Pacific Ocean and significant smaller than those found in the Atlantic Ocean.

Frigate Mackerel, Auxis thazard. Fish caught from coastal waters off Deerfield Beach, Florida, December 2020. Length: 81 cm (2 feet 8 inches). Catch, photograph and identification courtesy of Ben Cantrell, San Diego, California.  A most interesting large fish compared to those found in the Pacific Ocean.

The Frigate Mackerel, Auxis thazard, is one of the most common members of the Mackerel or Scombridae Family, that is also known as the Frigate Tuna and in Mexico as melva. Globally, there are two species in the genus Auxis, this species found in Mexican waters of both the Atlantic and the Pacific and a second species found in Mexican waters of the Pacific Ocean. The Frigate Mackerel found in Mexican waters of the Pacific Ocean is the subspecies Auxis thazard brachydorax.

The Frigate Mackerel has a robust elongated rounded fusiform tuna-like body. They are torpedo-shaped with no fins and are designed aerodynamically for speed. Dorsally, they are dark bluish with 15 or more fairly narrow oblique wavy lines above their lateral line; ventrally, they are silvery white. They have mid-sized black eyes and slender conical teeth. Their anal fin has 12 to 14 rays, and is small and followed by 7 finlets; their caudal fin is deeply forked with 2 small keels separated by 1 large keel at the base; their first dorsal fin has 10 to 12 spines; their second dorsal fin has 10 to 13 rays and followed by 8 finlets; and, their pectoral fins are short. The front portion of their body is covered with scales.

The Frigate Mackerel is a global pelagic highly migratory species found in both oceanic and coastal waters at depths up to 200 m (655 feet). They  reach a maximum of 62 cm (2 feet 0 inches) in length and 1.7 kg (3.8 lbs) in weight. As of January 1, 2023, the International Game Fish Association world record stood at 1.60 kg (3 lbs 8 oz) with the fish caught in coastal waters off Japan in November 2015. They normally travel in large schools at times mixed in with the Bullet Mackerel or Bullet Tuna, Auxis rochei. Each female releases between 78,000 and 1,400,000 eggs annually with the eggs and larvae being pelagic. The larvae from the two species of the Auxis genus are the most abundant of the tuna larvae. Due to their abundance they are considered an important component of the oceanic food web, particularly as food for larger fish. They feed on small fish, crustaceans, and squids. They have lifespans of five years. The Frigate Mackerel 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 Frigate Mackerel is a resident of all Mexican waters of the Atlantic including the Gulf of Mexico and the Caribbean. In the Pacific they are present in all waters with the exception of the northern half of the Sea of Cortez.

The Frigate Mackerel can very easily be confused with the Bullet Mackerel, Auxis rochei (15 or broad vertical bars).

From a conservation perspective the Frigate Mackerel are currently considered to be of Least Concern, with stable, widely distributed populations. They are considered an important commercial catch in certain parts of the world being caught by hook and line and as a by-catch in gill nets, purse seines, and traps at a level of 250,000 tons per year. They are marketed fresh, frozen, dried and salted, and smoked and canned. In the greater Los Cabos area they are an incidental catch on rapidly trolled feathers or hoochies or on fly-lined Flatiron Herring. They are used on a limited basis as fly-lined bait fish, chunk bait, or cut bait for fishing down deep.