Grouper

Groupers are fish that belong to the Epinephelinae subfamily of the Serranidae family of the order Perciformes. The Serranidae family includes the sea basses, however, not all of them are dubbed "groupers." Fish belonging to one of two big genera, Epinephelus and Mycteroperca, are commonly referred to as "grouper." Also known as groupers are species belonging to the tiny genera Anyperodon, Cromileptes, Dermatolepis, Graciela, Saloptia, and Triso. 

Coral groupers are fish belonging to the genus Plectropomus. All of these genera belong to the Epiphelinae subfamily. Several hamlets (genus Alphestes), hinds (genus Cephalopholis), lyretails (genus Variola), and other tiny genera (Gonioplectrus, Niphon, Paranthias) are also members of this subfamily, and some species in other serranid genera have common names that include the term "grouper." Nonetheless, the term "grouper" is commonly used to refer to the Epinephelinae subfamily.

Morphological Characteristics of Groupers Fish

• Teleosts with a strong body and a big mouth, groupers are Teleosts. 

• They aren't designed for swimming great distances or at high speeds. 

• They can grow to be quite huge, with lengths of over a metre, and the largest being the Atlantic goliath grouper (Epinephelus itajara), which weighed 399 kilogrammes (880 pounds) and measured 2.43 m (7 ft 11+12 in), though species vary widely in such a broad group. 

• Rather than biting off chunks of prey, they swallow it whole. 

• They don't have many teeth on the margins of their jaws, but inside the pharynx, they have massive crushing tooth plates. 

• Fish, octopuses, and crabs are among their favourite foods. Some species like to ambush their prey, while others are predators who hunt actively. 

• There have been no documented reports of deadly assaults on humans by the largest species, such as the giant grouper (Epinephelus lanceolatus).

• Their jaws and gills create a powerful vacuum that attracts prey from afar. They also use their teeth to burrow into sand and jet it out through their gills to construct shelters under large boulders.

• According to research, roaming coral groupers (Plectropomus pessuliferus) sometimes hunt with huge morays.

• Groupers (Epinephelinae) are carnivorous fish eaters who also eat invertebrates like octopuses and crustaceans. 

• On the vomerine and palatine bones, they have many rows of teeth along the jaw borders and in the roof of the mouth. 

• Some species have canine-like teeth that are larger. Crushing pharyngeal teeth help to augment the oral teeth.

Etymology

The word "grouper" comes from the Portuguese word garoupa, which is thought to have originated in a South American indigenous language. For certain species in Australia, such as the Queensland grouper, "groper" is used instead of "grouper" (Epinephelus lanceolatus). The wreckfish Polyprion oxygeneios, also known as hpuku in Mori, is referred to as "groper" in New Zealand. In the Philippines, groupers are known as lapu-lapu in Luzon and pugapo in Visayas and Mindanao. The fish is known as 'hammour' in the Middle East and is commonly consumed, particularly in the Persian Gulf region.

The tribes Grammistini and Diploprionini exude a mucus-like poison called grammistin in their skin, and when they are trapped in a small space and stressed, the mucus generates a foam that is toxic to adjacent fish, earning them the nickname soapfishes. Although the 5th Edition of the Fishes of the World puts these two groups as tribes within the Epinephelinae subfamily, they have been classified as their own families or subfamilies.

Reproduction in Groupers Fish

Groupers are primarily monoandric protogynous hermaphrodites, which means they only mature as females and can change sex after sexual maturity. Some grouper species develop around a kilogramme every year and are adolescent until they reach three kilos, at which point they become female. Males in charge of harems of three to fifteen females are common. Groupers frequently pair spawn, allowing giant males to prevent smaller males from reproducing. As a result, a little female grouper's fitness would suffer if it changed sex before being able to control a harem as a male. If there isn't a guy available, the largest female who can improve her fitness by switching sex will do so.

Some groupers, on the other hand, are gonochoristic. At least five times, gonochorism, or a reproductive strategy with two separate sexes, has developed independently in groupers. Gonochorism evolved as a result of large groups producing large quantities of habitat cover. In the presence of large males, both group spawning and habitat cover increase the likelihood of a smaller male reproducing. Male grouper fitness is linked to sperm production and consequently testicle size in circumstances where competitive exclusion of smaller males is impossible. Gonochoristic groupers had larger testes than protogynous groupers (10% of body mass vs. 1% of body mass), indicating that the evolution of gonochorism improved male grouper fitness in situations where large males could not competitively exclude tiny males from reproducing.

Parasites on Groupers Fish

Parasites such as digeneans, nematodes, cestodes, monogeneans, isopods, and copepods are found in groupers, as they are in other fish. According to a study conducted in New Caledonia, coral reef-associated groupers have roughly ten parasite types per fish species. Pseudo Rhabdo Sonchus species, monogeneans of the Diplectanidae family, are common and abundant in groupers.

Images of Groupers Fish

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Red Grouper Fish

The red grouper (Epinephelus morio) is a ray-finned marine fish that belongs to the Epinephelinae subfamily of the Serranidae family, which also contains anthias and sea basses.

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Potato Grouper

The potato grouper (Epinephelus tukula), sometimes known as the potato cod or potato bass, is a ray-finned fish that belongs to the Epinephelinae subfamily of the Serranidae family, which also contains anthias and sea basses.

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Peacock Grouper

Cephalopholis argus, also known as the peacock hind, roi, blue-spotted grouper, and heavenly grouper, is a ray-finned fish that belongs to the Epinephelinae family of groupers. The anthias and sea basses are also members of the Serranidae family.

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Humpback Grouper

The humpback grouper (Cromileptes altivelis), commonly known as the panther grouper or (in Australia) barramundi cod, is a ray-finned fish that belongs to the Epinephelinae subfamily of the Serranidae family, which also contains anthias and sea basses.

Uses of Grouper

Several species of grouper are significant food fish, and some are currently farmed. Unlike most other fish species, groupers are frequently sold live in marketplaces, rather than cooled or frozen. Many different species of fish are popular for sea angling. Some species are tiny enough to be kept in aquariums, however even these are prone to fast growth.

Ciguatera fish poisoning is usually associated with groupers. Because fish can be easily identified with molecular methods, even from meal leftovers, DNA barcoding of grouper species could aid in the control of Ciguatera fish poisoning.

Size 

A 180 kilogramme (400 lb) grouper was captured off the coast of Pulau Sembilan in the Strait of Malacca in January 2008, according to Malaysian daily The Star. At the Fuzhou Sea World aquarium, a 1.8 m (6 ft) grouper swallowed a 1.0 m (3 ft 3 in) whitetip reef shark, according to Shenzhen News.

A 2.3 m (7 ft 7 in) grouper was reported in Cieneguita, Limón, by a Costa Rican newspaper in September 2010. The fish weighed 250 kilogrammes (550 pounds) and was attracted with one kilogramme of bait. A 310 kg (680 lb) grouper was caught and sold to a hotel in Dongyuan, China, in November 2013.

In August 2014, off the coast of Bonita Springs, Florida (USA), a large grouper swallowed a 4-foot shark caught by an angler in one mouthful.

Ecology of Groupers Fish

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The 159 species of grouper (Family Epinephelidae) found around the world are extremely important ecologically, and many of them are commercially valuable wherever they are found. Many top-level predators in warm-temperate and tropical ecosystems are associated with deep-water and shallow hard-bottom reefs, and they follow pleistocene continental shelf and shelf edge shorelines. Their interactions with the environments in which they live are so striking in some cases that they appear to be keystone species and ecosystem engineers species that increase the complexity of the habitat and thus the diversity of the communities in which they live by their very presence or behaviours.

While each grouper species has its unique set of characteristics and individuals have their own quirks there are a few things that they all share. Many reef fish, including groupers, spawn offshore on shelf and shelf-edge reefs. 

Their pelagic larvae spend 40-60 days in the open ocean before arriving at inshore nursery grounds. They develop into little juveniles after they arrive, and they stay in their nursery habitat for periods ranging from 5 to 6 months (Gag) to 5 to 6 years (Red Grouper & Goliath Grouper). They then migrate to adult populations on the other side of the ocean. Each life stage has highly distinct requirements for survival as they move from habitat to habitat, occupying different niches based on their size and position in a food web, whether they eat plankton, bottom-dwelling crustaceans, or other fish.

Life histories and behaviours that they share are layered on top of this life cycle. They take a long time to grow, and their social systems are sophisticated, providing signs for sex change. They also show a high level of site fidelity inside their home ranges and at their spawning aggregation sites, where they are simple to catch, thanks to extraordinary advances in navigational gear that allow them to target highly specific locations.

Sex change

The transition from female to male sex in groupers is a one-way street. The onset of sex change in Gag (Mycteroperca microlepis), one of the more significant species fished in the eastern Gulf of Mexico, is brief, occurring only in late winter or early spring. Men and females are separated at other times, with males remaining offshore on spawning locations and females moving to shallower water. All of the population's reproduction occurs during the brief period when the sexes co-occur. All of the sex change cues work in the same way. If there are only a few males, dominant females will change sex so that more males are available the following spawning season.

Because of this combination of characteristics, they are extremely sensitive to exploitation and habitat degradation. There are currently no management plans in place to safeguard their social structure or nursery environment properly. While marine reserves have proven to be an effective tool for conserving offshore spawning grounds, they have yet to be implemented in nursery habitat, which is still vulnerable to eutrophication, development, and industrial contamination.

Spawning Aggregation

The number, size, and location of spawning aggregations in grouper vary along a more or less continuous spectrum. For example, compare the Nassau grouper Epinephelus striatus, which forms spectacularly large aggregations at specific locations for only a few days around the full moons of December and January, with Gag Mycteroperca microlepis and Scamp Mycteroperca phenax, which both form smaller aggregations over a broader area for about two or three months. Then there's the Red Grouper, Epinephelus morio, which doesn't seem to aggregate at all, and the Goliath Grouper, Epinephelus itajara, which gathers in aggregations of roughly 100 individuals in late summer and early fall (August - October).

Habitat

Because of their great commercial worth, groupers (family Serranidae) are found in stony and coral reefs throughout the tropics and subtropics of the world (161 species). They are also threatened by overexploitation from fishing, particularly for the live fish trade. The groupers developed as a particularly vulnerable group of fish among the commercially significant marine fishes. At least two of the 50 grouper species found in the Andaman Nicobar Islands are now endangered. In the Andaman and Nicobar Islands, one species, the big grouper (Epinephelus lanceolatus), is protected under Schedule I of the Wildlife (Protection) Act, 1972.

Hormonal Manipulation in Groupers

In many tropical and subtropical areas, particularly Southeast Asia, groupers are one of the most commercially important food fish (Kanemaru et al., 2012). In some species, juveniles differentiate and spawn as females for up to 14 years before undergoing sex reversal to males as long-lived protogynous hermaphrodites. Androgens, particularly 17-methyltestosterone (MT), and aromatase inhibitors, were used to promote sex change in order to overcome a scarcity of mature males for aquaculture. 

Unlike gonochoristic species that undergo permanent sex reversal when given steroids at the key phase of gonadal sex differentiation, groupers who are chemically treated while sexually immature often revert back to females the following spawning season. MT administration to juvenile fish modifies germ cell development from oogenesis to spermatogenesis, but not steroidogenic enzyme expression patterns, according to gene expression analyses. Permanent androgen-induced sex change appears to include ovarian cyp19a1a gene suppression and subsequent declines in serum oestrogen levels in both gonochoristic and hermaphroditic species. 

Species of Groupers Fish

The common species are Ep. tauvina (Greasy groupers), Ep. malabaricus (Speckled groupers), Ep. diacanthus (six banded reef cod), Ep. epistictus (Broker line groper), Ep. fasciatus (Red banded grouper), Ep. morrhua (Banded cheek reef cod), Ep. undulosus (Brown marbled grouper), Ep. merra (wire netting reef cod), Ep. fuscoguttatus (Brown marbled grouper), Ep. chlorostigma (Brown spotted grouper), Ep. longispinis (Spotted grouper), Ep. lanceolatus (Giant grouper), Cephalopholis sonnerati (Red coral cod) and Cephalopholis boenak (Blue lined sea bass).

Fun Facts

Grouper Facts

• Epinephelus itajara, the goliath, is the largest grouper in the Western Hemisphere, reaching 8 feet in length and weighing over 1,000 pounds.

• To spawn, individuals can travel up to 100 miles.

• These hardy fish can survive in brackish water and thrive in low-oxygen environments.

• Small goliath grouper (under 4 feet, or five to six years old) like mangroves, while larger adults prefer coral reefs.

• Mercury levels in goliath grouper captured in Belize exceeded the permissible levels for human consumption by 40%.

Queensland Grouper Facts

• The world's largest reef-dwelling bony fish is the Queensland grouper. The bodies of adults are mottled brown to dark grey and stocky. They are frequently spotted hovering in midwater or stationary on the bottom.