Grouper

Groupers are a diverse group of marine ray-finned fish. They belong to the family Epinephelidae. This family is part of the order Perciformes. For a long time, scientists thought they were a subfamily of seabasses. Now, they are treated as a distinct family. While the name "grouper" usually refers to the genera Epinephelus and Mycteroperca, many other fish share the name. This includes species in the genera Anyperidon, Cromileptes, Dermatolepis, Graciela, Saloptia, and Triso. Some fish, like those in the genus Plectropomus, are called "coral groupers."

Most groupers are teleosts with stout bodies and large mouths. They are not built for long-distance or fast swimming. Instead, they use a specialized mechanism to hunt. Their mouths and gills create a powerful vacuum. This vacuum pulls prey toward them from a distance. They do not bite pieces off their food. Instead, they swallow prey whole. They have heavy crushing tooth plates inside their pharynx, which is the throat area. This helps them process fish, octopuses, and crustaceans.

Groupers use their bodies for more than just hunting. They also use their mouths to dig into the sand. By jetting sand out through their gills, they create shelters under large rocks. Some species are ambush predators that wait for prey. Others are active predators that move around to find food. There are even interesting social behaviors observed in the wild. For example, roving coral groupers sometimes cooperate with giant morays to hunt. Groupers are also unique because they are one of the only animals that eat invasive red lionfish.

The name "grouper" has many different origins and meanings. The English word comes from the Portuguese name, garoupa. The scientific family name, Epinephelidae, comes from the genus Epinephelus. In ancient Greek, Epinephelus means "clouded over." This refers to a cloudy membrane that covers the eyes of many groupers. Names for these fish change depending on where you are in the world. In Australia, they are often called "groper." In the Philippines, they are known as lapu-lapu or pugapo. In the Middle East, they are called 'hammour.'

Groupers have a very interesting way of reproducing. Most are monandric protogynous hermaphrodites. This means they mature only as females first. Once they reach sexual maturity, they can change their sex to become males. Many species grow about one kilogram per year. They usually remain adolescents until they reach three kilograms. At that point, they become female. Large males often control harems. These harems can contain between three and 15 females.

Some groupers follow a different reproductive strategy called gonochorism. This means they have two distinct, permanent sexes. This trait has evolved independently in groupers at least five times. It is often linked to group spawning and the amount of habitat cover available. In environments where large males cannot exclude smaller males, gonochoristic groupers have evolved larger testes. Their testes can be 10% of their body mass. This is much larger than the 1% found in protogynous groupers. This change helps increase their fitness in those specific environments.

Groupers are also significant to human economies and health. Many species are important food fish, and some are farmed. Unlike many other fish, groupers are often sold alive in markets. This is seen in many parts of the world, including Malaysia. However, groupers can also be a source of ciguatera fish poisoning. Scientists use DNA barcoding to help identify species and control this poisoning. Because groupers can grow so large, they are sometimes caught by sea-anglers. The Atlantic goliath grouper is a massive example, weighing hundreds of kilograms and reaching over a meter in length.