| Epinephelus marginatus | |
|---|---|
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Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Perciformes |
| Family: | Serranidae |
| Subfamily: | Epinephelinae |
| Genus: | Epinephelus |
| Species: | E. marginatus |
| Binomial name | |
| Epinephelus marginatus (Lowe, 1834) | |
| Synonyms[2] | |
| |
Epinephelus marginatus (Latin pronunciation:[epiːˈnepʰelusmarɡiˈnaːtus]), thedusky grouper,yellowbelly rock cod oryellowbelly grouper, is a species of marineray-finned fish, agrouper from thesubfamilyEpinephelinae which is part of thefamilySerranidae, which also includes theanthias and sea basses. This species is the best known grouper species of theMediterranean Sea and North Africa coast.
Epinephelus marginatus is a very large, oval-bodied and large-headed fish with a wide mouth which has a protruding lower jaw.[3] The head and upper body are coloured dark reddish brown or greyish, usually with yellowish gold countershading on the ventral surfaces; the base colour is marked by a vertical series of irregular pale greenish yellow or silvery grey or whitish blotching which is normally rather conspicuous on the body and head; the black maxillary streak varies in its markedness; dark brown median fins; distal edges of theanal andcaudal fins and also oftenpectoral fins have narrow white terminal bands; thepelvic fins are black towards their tips while the pectoral fins are dark reddish-brown or grey; the margin of spinydorsal fin and basal part of the pectoral fins are often golden yellow in colour.[2] There are eleven spines and 13–16 soft rays in the dorsal fin. This species can grow up to 150 cm instandard length but is more often 90 cm.[4]
Epinephelus marginatus has two disjunct distribution centres, the main one is in the eastern Atlantic from the west coast of Iberia south along the western coast of Africa to theCape of Good Hope, extending east into the south-western Indian Ocean, as far as southernMozambique, with doubtful records fromMadagascar and possiblyOman. It is found throughout theMediterranean too. The second population occurs in the south western Atlantic off the coast of South America in southernBrazil,Uruguay and northernArgentina.[1] In the eastern Atlantic it is not normally found further north thanPortugal but there have been rare records from theBay of Biscay and in theEnglish Channel as far north as northernFrance,Great Britain andIreland.[5]
Epinephelus marginatus isdemersal, normally found in and around rocky reefs from surface waters down to as much as 300 metres in depth. It often occurs in the vicinity of beds ofPosidonia sea grass. Juveniles are generally found more inshore than the adult fish, even being found in rock pools. Where they are protected, in marine nature reserves and no take zones, both adults and juveniles occur in shallow waters, but the depths at which juveniles are found is always shallower than the preferred depths of adults.[3]
Epinephelus marginatus adults are solitary and territorial, preferring areas with a rocky substrate but both adults and juveniles will enter brackish waters, such as estuaries. Their main food ismolluscs,crustaceans, andoctopuses. But as they grow larger other fish form an increasingly important part of their diet, with reef fish being preferred.[2][3]
E. marginatus is aprotogynous hermaphrodite, meaning that all fish begin adult life as females but as they grow larger and older they develop into males. They attain sexual maturity at quite a late age, females begin to breed when they are around five years of age, and then between their 9th and 16th years they change into males, most commonly at 12.[3] The fish start to transform into males at a length of 65 cm,[6] although most change sex when they are between 80 and 90 cm in total length.[2] In some populations the presence of large female fish suggests that not all females change sex.[6] During the breeding season small clusters of a few tens of individuals form at specific spawning sites, an exception to their normally solitary existence. Known sites whereE. marginatus traditionally gather to spawn include theMedes IslandsMarine Reserve inSpain, offLampedusa inItaly andPort-Cros National Park inFrance, all in the Mediterranean; fishermen in Brazil suspect there are aggregations off the coast ofSanta Catarina but so far none has been definitely found.[6] In the Mediterranean spawning lasts from June to September, mating is polygynous and the spawning clusters normally have seven females to each male. Off BrazilE. marginatus reproduces in the early summer, between November and December.[7] While spawning, the dominant males set up territories and aggressively defend them from neighbouring males and smaller females. They are reported to live for up to 50 years.[3]
Epinephelus marginatus was first formallydescribed asSerranus marginatus in 1834 by theEnglishbotanist,ichthyologist,malacologist and clergymanRichard Thomas Lowe (1802–1874) with thetype locality given as "offMadeira".[8] The namePerca gigas was coined by theDanishzoologistMorten Thrane Brünnich (1737–1827) in 1768 but was unused and some authorities are of the view that this name should be suppressed by theInternational Commission on Zoological Nomenclature.[9]
Epinephelus marginatus is a popular food fish and is caught across its range by commercial fishermen while large adult fish are targeted as trophies byspear-fishing,[3] and is readily taken byanglers.[10] The slow growth rate of this species and its particular mode of reproduction make it vulnerable to over-exploitation, for example the targeting of large males by spear fishers may skew the sex ratio even further and affect reproductive productivity.[1] There have been attempts to grow and breed this fish inaquaculture in Italy.[11]
In some countries the dusky grouper is considered a delicacy. Referring to its preference among restaurant guests, the Spanish say 'De la mar el mero y de la tierra el carnero' (From the sea the dusky grouper, from the land the lamb).[12]
Epinephelus marginatus catch declined by 88% in seven countries between 1990–2001, these countries forming a significant part of its overall distribution. In other regions, such as West Africa, where this species is heavily exploited, there is little data about the status of this fish. For these reasons, theInternational Union for Conservation of Nature has assessed E. marginatus as being Vulnerable, citing a suspected reduction in the population size reduction in excess 50% over the last three generations and where the causes of the decline continue. Conservation measures have included a spearfishing ban for ten years in France and bag limits inSouth Africa. In addition, a number of Marine Protected Areas have been established to protect the habitat ofE. marginatus.[1] InTurkey recommended actions have included no take zones along the Aegean and Mediterranean Sea coasts and a total fisheries ban for a minimum of 3–5 years.[13]
