Grouper
The word “grouper” comes from Portuguese “garoupa”. One interesting fact to know is that in New Zealand and Australia, the name for several species of Grouper is referred to as Groper, as in the Epinephelus lanceolatus Queensland Groper. In the Middle East, the fish is known as Hammour, and is widely eaten, especially in the Gulf Region.
Groupers usually have a stout body and a large mouth and are not built for long-distance fast swimming. They can be quite large, and lengths over a meter and weights up to 100 kg are not uncommon, though obviously in such a large group species vary considerably. They swallow prey rather than biting pieces off it.
They do not have much tooth on the edges of their jaws, but they have heavy crushing tooth plates inside the pharynx. They habitually eat fish, octopus, crab and lobster. They prefer to catch their prey by waiting for them to approach, instead of swimming after them. According to the film-maker Graham Ferreira, there is at least one record, from Mozambique, of a human being killed by one of these fish.
Their mouth and gills form a powerful sucking system that sucks their prey in from a distance. They also use their mouth to dig into sand in order to form their shelters under big rocks, jetting it out through their gills. Their gill muscles are so powerful, that it is nearly impossible to pull them out of their cave if they feel attacked and extend them in order to lock themselves in. There is some research indicating that roving coralgroupers sometimes join with giant morays when hunting.
Most fish spawn between May and August. The young are predominantly female but transform into males as they grow larger. They grow about a kilogram per year. Generally they are adolescent until they reach three kilograms, when they become female. At about 10 to 12 kg they turn to male. Usually, males have a harem of three to fifteen females in the broader region. In the rare case that no male exists closeby, the largest female turns faster. Most males look much wilder and bigger than females, even if they happen to be smaller.
Many groupers are important food fish, and some of them are now farmed. Unlike most other fish species which are chilled or frozen, groupers are generally sold alive in markets. Any species are popular flish for sea-angling. Some species are small enough to be kept in aquaria, though even the small species are inclined to grow rapidly.
The species Epinephelus lanceolatus can grow very large: there have been reports of them growing big enough to swallow a human bather or even a scuba diver: for example, Arthur C. Clarke wrote that while scuba diving in an inlet on the coast of Sri Lanka he saw a grouper about 20 feet long, and 4 feet thick side to side, living in a sunken floating dock.
Swallowing an ordinary open-circuit scuba diver would need a throat that can expand to about 2 feet square. It could be that Epinephelus lanceolatus does not grow that big more often because it needs a big enough shelter to hide from attack by sharks or seals, and that the situation may change if the current worldwide decimation of sharks for the shark fin trade continues.