White Grunt

Haemulon plumieri

These schooling reef fish have almond shaped bodies with pointed snouts and forked caudal (tail) fins. They are generally silvery white or cream, with touches of bronze or yellow, and striped with blue at their heads. Their mouths are red, and they make a grunting noise by grinding their teeth together. They have been seen in confrontations, open mouths pressed together, pushing against each other for dominance.

Order – Perciformes
Family – Haemulidae
Genus – Haemulon
Species – plumieri

Common Names

English language common names are white grunt, black grunt, boar grunt, common grunt, flannelmouth grunt, gray grunt, grunt, Key West grunt, redmouth grunt, ruby red lips, and white snapper. Common names in other languages include aosuji-isaki, bocayate blanco, bococolorado, boquicolorado, cachicata, coro coro margariteno, gorette blanche, hemulon arara, jolle cocoon, roncadot, ronco blanco, ronco grande, ronco margariteno, ronco-ronco, and sard grise.

Importance to Humans

White grunt is considered good quality fish for human consumption and is typically marketed fresh. They are part of a historic Florida dish, “Grits and Grunts”. Although usually served as a panfish, some are large enough to provide small fillets. This fish has been linked to ciguatera poisoning. Although it is of minor commercial importance, white grunt is considered a recreational gamefish. It is caught primarily by hook and line off the southeastern U.S., but is also taken with fish traps, bottom trawls, and seines. In Haiti it is sometimes collected with dynamite. The white grunt is also collected for public aquarium displays.

Conservation

The white grunt is not listed as endangered or vulnerable with the World Conservation Union (IUCN). The IUCN is a global union of states, governmental agencies, and non-governmental organizations in a partnership that assesses the conservation status of species.

> Check the status of the white grunt at the IUCN website.

Geographical Distribution

The distribution of the white grunt is limited to the western Atlantic Ocean, from the Chesapeake Bay to the eastern Gulf of Mexico and Caribbean Sea, south to Brazil. It has also been introduced to Bermuda. It occurs rarely in waters north of South Carolina (U.S.).

Habitat

The white grunt is commonly found from the shoreline to the outer reef edge to depths of 80 feet (24 m) and occasionally offshore over hard bottoms to depths of 115 feet (35 m). The adults form schools with other species of fish (H. sciurus,H. flavolineatum, Acanthurus chirurgus, Mulloidichthys martinicus, and others) during the day over coral reefs or sandy bottoms. Juvenile white grunts reside inshore in seagrass beds, seeking the shelter among the spines of the long-spined sea urchin (Diadema antillarum). These juveniles organize into schools according to size. Grunts produce grunting sounds, hence their common name, by grinding the pharyngeal teeth, amplifying the sound with the air bladder. The white grunt frequently exhibits territorial kissing displays, consisting of two fish in confrontation, pushing each other on the lips with mouths open wide.

Biology

Distinctive Features
The body is moderately elongate, with an elevated and compressed back. The head is long with a sharp snout. Dorsal and anal fins of the white grunt are completely covered with scales. The caudal fin is forked and the pectoral fin long and falcate. The scales above the lateral line are larger than those scales located below the lateral line.

Coloration
The white grunt is silvery white to cream-colored, the head is bronze to yellow dorsally while the ventral side of the head and belly is white. There is a series of dark blue stripes on the head, margined with yellow-bronze running back into the body. Each scale’s margin is bronze and the posterior edge is often gray. Scale rows above the lateral line are larger than those below the lateral line. The spinous dorsal fin is chalky to yellowish-white, the soft dorsal, soft anal, and caudal fins are brownish gray. The pelvic fins are chalky, while the pectoral fins range from light yellow to chalky in color. A black blotch is located on the preopercle and the inside of the mouth is red. The color of this fish is changeable, with the fish appearing in a shade matching the immediate surroundings. Over sand, near coral, even the darkest spots may fade to a pale yellow color.

Size, Age, and Growth
Commonly reaching lengths of 17 inches (45 cm) and weights of 5.5 pounds (2.5 kg), the white grunt is not a large fish. The maximum reported length is 18 inches (46.0 cm) and weight is 9.7 pounds (4.38 kg). White grunts reach sexual maturity is attained during the third year of life when males reach 7.8 inches (20 cm) in length and females 8.6 inches (22 cm) in length. Maximum age for the white grunt is believed to be between 9 and 12 years. Studies have shown white grunt growth rates are most rapid during the first 30 days of life when average daily growth is .32mm/day. The average monthly growth rate of adults is 1.4-3.6 mm/day.

Dentition
Lacking canines, grunts have small, dense, and blunt teeth on the jaws. There are no teeth located on the roof of the mouth. The pharyngeal teeth are well developed and used for producing the grunting sounds that gives this fish its common name.

Food Habits
The white grunt feeds nocturnally, migrating off the reefs to open sandy, muddy, or grassy areas. Typically moving off the reef shortly after sunset and returning to the reef just prior to sunrise, large white grunts are the first to leave and last the return. This fish is considered a generalized carnivore, scavenging benthic crustaceans, mollusks, echinoderms, and small fishes. Grunts have also been observed to feed on material attached to pilings near offshore platforms. The small juvenile grunts pick plankton, primarily copepods, from the water column during daylight hours.

Reproduction
Peak spawning occurs during much of the year with peaks occurring during May and June off Florida, August and September off Puerto Rico and in March and April off Jamaica. The white grunt spawns offshore, over hard bottoms or reefs. There are no detailed observations on spawning behavior, however it has been observed that pairs of white grunts sometimes face and push each other with open mouths. It is not known whether this is courtship or territorial behavior. The 0.9 mm diameter eggs are pelagic and transparent. Hatching 20 hours after fertilization, larvae range from 2.7-2.8 mm in length and contain white pigment scattered throughout the body. Within 48 hours after hatching, the larvae begin to actively feed. The juveniles develop a dorsal body stripe at lengths of 23-39 mm. As they mature, pigmentation is less intense and stripes fade and there is no definite pattern other than the prominent caudal spot. The juveniles occur in shallow water in a variety of habitat types, including seagrass beds, sand flats, rocky shorelines, and coral reefs.

Parasites
Monogean, digean, acanthocephalan, nematode, and cestode parasites have all been found associated with the white grunt. Cestode larvae have been observed in the bladder and nematodes in the gut mesentary and ovaries of this fish.

Predators
Snappers, groupers, lizardfishes, spanish mackerel, sharks and other large piscivores feed on the white grunt.

Taxonomy

The white grunt was first described in 1801 by Bernhard G.E. Lacepede, a French naturalist. It was originally given the scientific name of Labrus plumierii, but changed by later workers to the current name of Haemulon plumieri. This name originates from the greek “haimaleos” meaning blood gums, referring to the red coloration of the mouth interior. Synonyms include Guabi coarca brasiliensibus Marcgrave 1648, Perca marine capite striato Catesby 1743, Perca formosa Linnaeus 1766, Labrus plumierii Lacepede 1802, Haemulon formosum Cuvier 1829, Haemulon arcuatum Valenciennes 1833, Labrus plumieri Cuvier 1834, Haemulon parae Castelnau 1855, Haemulon arara Poey 1860, Haemulon subarcuatum Poey 1861, Haemylum formosum Scudder 1863, Haemylum arara Scudder 1863, Haemulum formosum Cope 1871, Diabasis formosus Goode and Bean 1883, and Haemulum plumierii Meek and Hildebrand 1925.

Prepared by: Cathleen Bester