Bullet Mackerel, Auxis rochei
The Bullet Mackerel, Auxis rochei, whose common Spanish name is melvera, 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 Bullet Tuna. Globally, there are only two species in the genus Auxis, this species found in Mexican waters of the Pacific and a second species found in Mexican waters of both the Atlantic and the Pacific. The Bullet Mackerel found in Mexican waters of the Pacific is the subspecies Auxis rochei eudorax.
The Bullet 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 broad nearly vertical bars 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 7 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 9 to 12 spines and 10 to 13 rays, and the second being small and followed by 8 finlets. Their pectoral fins are short. The front portion of their body is covered with scales.The Bullet 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 55 cm (22 inches) and weight of 1.8 kg (4 pounds). They normally travel in large schools at times mixed in with the Frigate Mackerel or Frigate Tuna, Auxis thazard. Each female releases between 31,000 and 103,000 eggs annually with the eggs and larvae being pelagic. The larvae from the two species of Auxis are the most abundant of all 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 Bullet Mackerel is found in all waters of the Pacific with the exception that they are absent from of the northern half of the Sea of Cortez.
The Bullet Mackerel is very similar to and can be very easily be confused with the Frigate Mackerel, Auxis thazard (15 or more broad oblique to horizontal bars beginning under the first dorsal and pectoral fins).
The Bullet Mackerels are considered an important commercial catch in certain parts of the globe 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.
Bullet Mackerel, Auxis rochei. Fish caught off Point Palmilla, Baja California Sur, November 2015. Length: 25.0 cm (9.8 inches).