Several types of fish go by the common name grouper, a collection of fish prized for its economic value as a menu item and commercial fishing. Size, color and geographic range vary greatly for different species. The black grouper, for example, is a particularly large and popular species for commercial fishing operations and can reach over 4 feet long and weigh close to 180 pounds.
Common Name vs. Classification
The term "grouper" sometimes refers to a few different types of fish in the family Serranidae. This family includes true groupers, sea bass and fairy basslets. More commonly, however, groupers are any fish in the subfamily Epinephelinae, particularly those in the genera Epinephelus and Mycteroperca.
Groupers are a diverse group, but a few characteristics are shared by most. Groupers are known for their camouflage skills; many species are speckled with colors similar to the reefs they inhabit, which hides them from both predators and prey. In addition, some can change their colors. Most lack teeth, but instead have powerful plates in their pharynx that allows them to hold and crush their prey. Groupers exhibit protogyny, meaning they change sex from female to male. Groupers tend to be solitary fish, but form large aggregations during spawning time, which in turn can lead to over-fishing.
Range and Habitat
Groupers live in every ocean, although habitat preferences vary greatly between species. In general, groupers are reef-dwellers in tropical and subtropical waters. The juveniles of many species tend to live in seagrass beds near the shore until they reach maturity and are large enough to inhabit the sometimes dangerous reefs. Time to maturity varies greatly by species: goliath groupers may stay in their nursery habitats for five to six years while the gag grouper may remain for as little as five to six months.
Role in Food Chain
Groupers as a group tend to be pivotal members in the delicate food chains of coral reefs. As ambush predators, these fish lie in waiting for smaller fish to pass by. Since many species lack teeth, they rely on the powerful sucking motion created by their gills. Other species, such as the camouflage grouper, have many short, spiky teeth that aid in feeding. They are dominant as predators, eating anything that will fit in their mouths. Most hide in caves or crevices along the reef and are slow-moving fish that tend to stick close to home. Although they are powerful predators, larger fish such as hammerhead sharks, barracuda, moray eels and mackerel feed on groupers.