Cero, Scomberomorus regalis

Cero, Scomberomorus regalis. Fish caught from coastal waters off the Florida Keys, December 2014. Length: 30 cm (12 inches). Catch, photograph, and identification courtesy of Ben Cantrell, Peoria, Illinois.

Cero, Scomberomorus regalis. Fish caught from coastal waters off Islamorada, Florida, January 2016. Length: 51 cm (20 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).

The Cero, Scomberomorus regalis, is a member of the Mackerel or Scombridae Family, that is also known as the Cero Mackerel and the Painted Mackerel and in Mexico as sierra. Globally there are eighteen species in the genus Scomberomorus, of which five are found in Mexican waters, three in the Atlantic and two in the Pacific Ocean.

The Cero has an elongated fusiform, strongly compressed, torpedo-shaped body. Dorsally they are an iridescent bluish-green with the sides and belly silvery in color. They have a mid-lateral bronze stripe that runs from the pectoral fin to the base of the caudal fin and yellow-orange streaks along with three or four rows of small yellow spots above and below the lateral stripe. The anterior third of the first dorsal fin is bluish-black. Their head has a short pointed, snout with a mid-sized mouth that extends to the margin of the eyes and is equipped with a single row of large uniformly sized closely spaced teeth on each jaw. Their anal fin does not have spines but has 15 to 20 rays and is followed by 7 to 9 finlets; their caudal fin is deeply forked with 1 large and 2 smaller keels at its base; their first dorsal fin has 16 to 18 spines; their second dorsal fin has 15 to 19 rays and closely follows the first and is higher and similar in shape to the anal fin and is followed by 7 to 9 finlets; their pectoral fins are short; and their pelvic fins are long. They have 11 to 14 gill rakers. Their body is covered with small scales. Their lateral line gradually curves down toward the caudal fin base.

The Cero is a coastal pelagic schooling species found in the subtropical and tropical waters off North America and the Caribbean. They are normally found as solitary individuals and occasionally in schools over coral reefs, wrecks, and along ledges in the upper portions of the water column at depths up to 20 m (65 feet). They reach a maximum of 89 cm (2 feet 11 inches) in length and 7.8 kg (17 lbs 3 oz) in weight. As of March 31, 2023, the International Game Fish Association world record for length stood at 65 cm (2 feet 2 inches) caught in coastal waters off Key West, Florida in November 2021. They are a voracious opportunistic shallow water predator that feeds on herrings, silversides, shrimp and squid. They have the ability to swim at speeds of up to 48 kph (30 mph). In turn they are preyed upon by Wahoo, numerous Sharks, Dolphins and sea birds. Reproduction is oviparous with each female releasing between 160,000 and 2,230,000 eggs into the water column that are quickly fertilized by males. Eggs are pelagic and generally hatch within twenty-five hours. The Cero 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 Cero is very similar and easily confused with the Spanish Mackerel, Scomberomorus maculatus (lacks the long thin stripe on the side; anterior of second dorsal not black), and the King Mackerel, Scomberomorus cavalla. (lateral line dips below the second dorsal; 6 to 10 gill rakers; anterior of second dorsal not black except in juveniles).

In Mexican waters the Cero is a resident of Mexican waters of the Atlantic but has a limited distribution being found around the Yucatán Peninsula in both the Gulf of Mexico and the Caribbean.

From a conservation perspective the Cero is currently considered to be of Least Concern with stable, widely distributed populations. They are not a significant commercial species but in some parts of their region they are pursued by commercial fishermen via hook and line, gill nets and purse seines. They are a popular sport fish due to the speed, agility and quality as a food fish although they are known to contain ciguatoxin. They are frequently encountered by divers but normally flee.