Frigate Mackerel

Frigate Mackerel, Auxis thazard

The Frigate Mackerel, Auxis thazard, whose common Spanish name is melva, is one of the most common members of the Mackerel or Scombridae Family, known collectively as macarelas in Mexico. This fish is also known as the Frigate Tuna. Globally, there are only 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. The Frigate Mackerel found in Mexican waters of the Pacific is the subspecies Auxis thazard brachydorax.

The Frigate Mackerels have robust elongated rounded fusiform tuna-like bodies. 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 is small with 12 to 14 rays and seven finlets. Their caudal fin is deeply forked with two small keels separated by one large keel at the base. They have two widely separated dorsal fins, the first having 10 to 12 spines and 10 to 13 rays, and the second being small and followed by eight finlets. Their pectoral fins are short. The front portion of their body is covered with scales.

The Frigate Mackerels are a global pelagic highly migratory species found in both oceanic and coastal waters at depths up to 200 meters (655 feet). They  reach a maximum length of 62 cm (24 inches) and weight of 1.7 kg (3.8 pounds). 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 1.4 million 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 a lifespan of five years. Very little is known about their behavioral patterns.

In Mexican waters the Frigate Mackerel are found in all waters of the Atlantic. 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 more broad vertical bars).

The Frigate Mackerels 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. They are used on a limited basis as fly-lined bait fish, chunk bait, or cut bait for fishing down deep. From a conservation perspective they are currently classified as of Least Concern, being widely distributed and very abundant in some locations.

Frigate Mackerel, Auxis thazard. Fish caught off Point Palmilla, Baja California Sur, September 2015. Length: 36 cm (14 inches).