Cottonwick, Haemulon melanurum

Cottonwick, Haemulon melanurum. Fish caught from coastal waters off Ft. Lauderdale, Florida, July 2021. Length: 15 cm (5.9 inches). Catch, photograph, and identification courtesy of Chris Moore, Peoria, Arizona.

Cottonwick, Haemulon melanurum. Fish caught from coastal waters off Cancun, Quintana Roo, August 2013 Length: 14 cm (5.5 inches). Catch, photograph and  identification courtesy of Dominick Porcelli, Lighthouse Point, Florida.

Cottonwick, Haemulon melanurum. Fish caught from coastal waters off Ft. Lauderdale, Florida, August 2021. Length: 15 cm (5.9 inches).  Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

The Cottonwick, Haemulon melanurum, is a member of the Grunt or Haemulidae Family, that is also known as the Cottonwick Grunt and in Mexico as ronco lomo manchado. Globally, there are twenty-one species in the genus Haemulon, and all twenty-one are found in Mexican waters, fourteen in the Atlantic and seven in the Pacific Ocean.

The Cottonwick has and oblong, elongated, compressed body that has a depth that is 34% to 37% of standard length. The adults are an overall silvery gray with a black stripe, that widens toward the rear, along the upper back and lower part of the dorsal fin that extends through the upper half of the caudal peduncle, the joins a horizontal black “V” on the caudal fin, affording for an easy identification. Their head and body have up to 7 faint yellow stripes. Their anal, pectoral and pelvic fins are white. The inside of their mouth is red. The juveniles have four black stripes, one just above the centerline, one from the upper snout that runs above the eye along the upper back and upper caudal base, one thin stripe that runs from the top of the eye back along the lateral line and curves down to join the lower stripe in front of the caudal base, and one that runs from the snout, through the eye to the caudal fin base. Their head is bluntly pointed with a slightly convex upper profile, a small terminal mouth, and two large pores on the underside of the chin. Their anal fin has 3 spines and 8 or 9 rays, their caudal fin is forked; their dorsal fin is continuous with 12 spines, a small notch, and 15 to 17 rays. They have 26 to 28 gill rakers. They are covered with rough scales with the scale rows below the lateral line being oblique.

The Cottonwick is found in clear water within reefs and over hard substrate at depths up to 50 m (165 feet). The juveniles are found inshore within vegetation; the adults are found offshore often in large schools. They reach a maximum of 43 cm (17 inches) in length and 0.55 kg (1 lb 3 oz) in weight. The feed primarily on crustaceans. Reproduction is oviparous with distinct pairing during breeding season. The Cottonwick 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 Cottonwick is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico, with the exception that they are absent from the Texas border to Tuxpan, Veracruz, and the east coast of the Yucatán Peninsula in the Caribbean.

The Cottonwisk is a fairly easy identification due to its markings. If confused it would be with either the Bluestriped Grunt, Haemulon sciurus (numerous bluish-white stripes on the sides) and Caesar Grunt, Haemulon carbonarium (ten thin stripes on the sides).

From a conservation perspective they are currently considered to be of Least Concern, being widely distributed with stable to slightly decreasing populations. They are pursued by artisanal, commercial and recreational fishermen being caught with hook-and-line, spears, and traps and considered to be a quality food fish primarily sold in local fish markets, however, they are known to contain ciguatoxin. They are also utilized by the aquarium trade including public aquariums. They are prone to regional overfishing and are a known component of the diet of the highly invasive. In a large school they are considered by underwater divers to be an exceptional species.