Mackerel Scad, Decapterus macarellus
The Mackerel Scad, Decapterus macarellus, whose common Spanish name is macarela caballa, is a member of the Jack or Carangidae Family, known collectively as jureles and pámpanos in Mexico. There are twelve global members of the.genus Decapteurs, five of which are found in Mexican waters, two in the Atlantic, two in the Pacific, and one in both oceans.
The Mackerel Scads have “mackerel-like” elongated slender cylindrical bodies with a depth that is 16 to 20% of standard length. The top and rear ends of their upper jaw are straight and the lower corner is angular. They are bluish-green dorsally and silvery ventrally. They have a small black blotch on the upper edge margin of their gill cover. The anal fin base is relatively short and their second dorsal fin base is long; and, the pectoral fin is slightly longer than half their head length. They have 34 to 41 gill rakers and 28 to 33 scutes. Their lateral line has a long low arch anteriorly. Keys to identification are the 110 to 138 scales and scutes on the straight portion of their lateral line and the scales on top of their head that extend forward to the anterior margin of the pupil.
The Mackerel Scad are a pelagic species found mainly in oceanic waters at depths up to 1,310 feet. They reach a maximum length of 46 cm (18 inches). They are a poorly studied species and very little is known about their behavior patterns.
In Mexican waters the Mackerel Scads have a limited range being found only in the southern fourth of the Sea of Cortez.
The Mackerel Scad can be easily confused with the Amberstripe Scad, Decapterus muroadsi (scales on head but less than 20 scales on straight portion of lateral line), the Shortfin Scad, Decapterus macrosoma (no scales on head), and the Jack Mackerel, Trachurus symmetricus (numerous strong scutes; arched lateral line). Note: There are three Scads of the Decapterus genus residing in Mexican waters of the tropical Eastern Pacific that are exceedingly difficult to separate: the Amberstripe Scad, Decapterus muroadsi, the Mackerel Scad, Decapterus macarellus, and the Shortfin Scad, Decapterus macrosoma. They can only be identified conclusively via microscopic examination to determine the shape of their jaw bone and the scale count within the flat section of their lateral line.
The Mackerel Scads show up in the San José River basin in the greater Los Cabos area during the cold water periods between December and February when they can be caught in abundance on Sabiki type rigs out of 300-foot water. They survive bait tanks well and are utilized as live fly-lined or troll bait to target the larger big game fish such as dorado, marlin, and tuna. They are harvested in some parts of the world in large quantities and sold commercially for human consumption, however, if retained past the daily outings in the Los Cabos area, they are frozen and used later as dead fly-lined or trolled bait.
Mackerel Scad, Decapterus macarellus. Fish caught from coastal waters off Point Palmilla, Baja California Sur, November 2015. Length: 32 cm (13 inches). Fish identification courtesy of H.J. Walker, Jr., Scripps Institution of Oceanography, La Jolla, CA.