Groupers are a diverse group of marine Actinopterygii in the family Epinephelidae, in the order Perciformes.
Groupers were long considered a subfamily of the seabasses in Serranidae, but are now treated as distinct. Not all members of this family are called "groupers". The common name "grouper" is usually given to fish in one of two large genus: Epinephelus and Mycteroperca. In addition, the species classified in the small genera Anyperidon, Cromileptes, Dermatolepis, Graciela, Saloptia, and Triso are also called "groupers". Fish in the genus Plectropomus are referred to as "coral groupers". These genera are all classified in the subfamily Epiphelinae. However, some of the hamlets (genus Alphestes), the hinds (genus Cephalopholis), the lyretails (genus Variola), and some other small genera ( Gonioplectrus, Niphon, Paranthias) are also in this subfamily, and occasional species in other serranid genera have common names involving the word "grouper". Nonetheless, the word "grouper" on its own is usually taken as meaning the family Epinephelidae.
Description
Groupers are
, typically having a stout body and a large mouth. They are not built for long-distance, fast swimming. They can be quite large: in length, over a meter. The largest is the Atlantic goliath grouper (
Epinephelus itajara) which has been weighed at and a length of ,
though in such a large group, species vary considerably. They swallow prey rather than biting pieces off of them. They do not have many teeth on the edges of their jaws, but they have heavy crushing tooth plates inside the
pharynx. They habitually eat
fish,
, and
. Some species prefer to
Ambush predator, while others are active predators. Reports of fatal attacks on humans by the largest species, such as the
giant grouper (
Epinephelus lanceolatus), are unconfirmed.
Their mouths and form a powerful vacuum that pulls their prey in from a distance. They also use their mouths to dig into sand to form their shelters under big rocks, jetting it out through their gills.
Research indicates roving coralgroupers ( Plectropomus pessuliferus) sometimes cooperate with in hunting.
Systematics
Etymology
The word "grouper" is from the Portuguese name,
garoupa, which has been speculated to come from an indigenous South American language.
The family name Epinephelidae comes from the type genus
Epinephelus, which means "clouded over" in ancient Greek, referencing the cloudy membrane covering the eyes of most groupers that would have been known to European scientists at the time of description.
In Australia, "groper" is used instead of "grouper" for several species, such as the Queensland grouper ( Epinephelus lanceolatus). In New Zealand, "groper" refers to a type of wreckfish, Polyprion oxygeneios, which goes by the name hapuka (from the Māori language hāpuku).
In previous taxonomic treatments, the soapfishes of the Grammistini and Diploprionini were treated as tribes within the subfamily Epinephelinae.
Classification
Based on
Eschmeyer's Catalog of Fishes:
-
Family Epinephelidae Pieter Bleeker, 1874 (groupers)
-
Aethaloperca Fowler, 1904
-
Alphestes Bloch & Schneider, 1801
-
Anyperodon Günther, 1859
-
Cephalopholis Bloch & Schneider, 1801
-
Chromileptes William Swainson, 1839
-
Dermatolepis Gill, 1861
-
Epinephelus Bloch, 1793
-
Gonioplectrus Gill, 1862
-
Gracila Randall, 1964
-
Hyporthodus Gill, 1861
-
Mycteroperca Gill, 1862
-
Paranthias Guichenot, 1868
-
Plectropomus Lorenz Oken, 1817
-
Saloptia J.L.B. Smith, 1964
-
Triso Randall, Johnson & Lowe, 1989
-
Variola Swainson, 1839
Reproduction
Groupers are mostly monandric protogynous hermaphrodites, i.e., they mature only as females and can change sex after sexual maturity.
[Erisman, B. E., M. T. Craig, and P. A. Hastings. 2009. A phylogenetic test of the size-advantage model: Evolutionary changes in mating behavior influence the loss of sex change in a fish lineage. American Naturalist 174:83-99.][DeMartini, E. E., A. R. Everson and R. S. Nichols. 2011. Estimates of body sizes at maturation and sex change and the endemic Hawaiian grouper's spawning seasonality and sex ratio ( Hyporthodus queries, f. Epinephelidae). Fishery Bulletin 109:123-134.] Some species of groupers grow about a kilogram per year and are generally adolescents until they reach three kilograms when they become female. The largest males often control harems containing three to 15 females.
[Sadovy, Y. and P. L. Colin. 1995. Sexual development and sexuality in the Nassau grouper. Journal of Fish Biology 46:961-976.] Groupers often pair spawn, which enables large males to competitively exclude smaller males from reproducing.
[Allsop, D. J. and S. A. West. 2003. Constant relative age and size at sex change for sequentially hermaphroditic fish. Journal of Evolutionary Biology 16:921-929.][Munoz, R. C. and R. R. Warner. 2003. A new version of the size-advantage hypothesis for sex change: Incorporating sperm competition and size-fecundity skew. American Naturalist 161:749-761.][Kuwamura, T. 2004. Sex change in fishes: Its process and evolutionary mechanism. Zoological Science 21:1248-1248.] As such, if a small female grouper were to change sex before it could control a harem as a male, its fitness would decrease.
If no male is available, the largest female that can increase fitness by changing sex will do so.
However, some groupers are gonochoristic.[Erisman, B. E., J. A. Rosales-Cassian and P. A. Hastings. 2008. There is evidence of gonochorism in a grouper, Mycteroperca rosacea, from the Gulf of California, Mexico. Environmental Biology of Fishes 82:23-33.] Both group spawning and habitat cover increase the likelihood of a smaller male reproducing in the presence of large males. The fitness of male groupers in environments where competitive exclusion of smaller males is impossible is correlated with sperm production and thus testicle size.[Molloy, P. P., N. B. Goodwin, I. M. Cote, J. D. Reynolds, and M. J. G. Gage. 2007. Sperm competition and sex change: A comparative analysis across fishes. Evolution 61:640-652.] Gonochoristic groupers have larger testes than protogynous groupers (10% of body mass compared to 1% of body mass), indicating the evolution of gonochorism increased male grouper fitness in environments where large males were unable to competitively exclude small males from reproducing.
Parasites
Like other fish, groupers harbor
, including
,
[Cribb, T. H., Bray, R. A., Wright, T. & Pichelin, S. 2002: The trematodes of groupers (Serranidae: Epinephelinae): knowledge, nature, and evolution. Parasitology, 124, S23-S42.] ,
,
,
, and
. A study conducted in
New Caledonia has shown that
coral reef-associated groupers have about ten species of parasites per fish species.
[Justine, J.-L., Beveridge, I., Boxshall, G. A., Bray, R. A., Moravec, F., Trilles, J.-P. & Whittington, I. D. 2010: An annotated list of parasites (Isopoda, Copepoda, Monogenea, Digenea, Cestoda and Nematoda) collected in groupers (Serranidae, Epinephelinae) in New Caledonia emphasizes parasite biodiversity in coral reef fish. Folia Parasitologica, 57, 237–262. PDF] Species of
Pseudorhabdosynochus, monogeneans of the family
Diplectanidae are typical of and especially numerous on groupers.
Modern use
Many groupers are important food fish; some are now
fish farming. Unlike most other fish species, which are chilled or frozen, groupers are usually sold alive in markets.
Many species are popular
game fish for
big-game fishing. Some species are small enough to be kept in
aquarium, though even the small species are inclined to grow rapidly.
Groupers are commonly reported as a source of ciguatera fish poisoning.[Schoelinck, C., Hinsinger, D. D., Dettaï, A., Cruaud, C. & Justine, J.-L. 2014: A phylogenetic re-analysis of groupers with applications for ciguatera fish poisoning. PLoS ONE, 9, e98198. ]
Size
Malaysian newspaper
The Star reported a grouper being caught off the waters near
Pulau Sembilan in the Strait of Malacca in January 2008.
Shenzhen News in China reported that a grouper swallowed a whitetip reef shark at the Fuzhou Sea World aquarium.
In September 2010, a Costa Rican newspaper reported a grouper in Cieneguita, Limón. The weight of the fish was , and it was lured using one kilogram of bait.
In August 2014, off Bonita Springs in Florida (USA), a big grouper took in one gulp a 4-foot shark that an angler had caught.
See also
External links
