Size : The grouper is a large fish, which can measure up to 150 cm. Usually, however, the specimens most commonly measure 80-100 cm.

Depth : The grouper frost lives between 10 and 50 meters deep. Younger specimens can also be encountered in more superficial waters. In any case, it goes up to 200 meters deep.

Distribution : The grouper has a very wide distribution area, ranging from the Mediterranean Sea to the Atlantic coasts: from the British Isles to South America (Brazil, Argentina, Uruguay) and from the western coasts of Africa to the Indian Ocean (Madagascar)

Living habits : Carnivorous fish, it is a great predator. It feeds on cephalopods, crustaceans and other fish. This leads her to be a curious animal, but also highly territorial. Due to fishing it is not uncommon for it to have shy behaviors which, however, give way to indifference within many protected areas where the animal does not feel threatened. In order not to alarm the grouper, in order to take photographs or to observe the animal closely, direct eye contact (eyes in the eyes) should be avoided when approaching.

Environments where it is possible to observe it : The brown grouper prefers rocky environments with shelters and cavities in which it can hide. The articulation of the seabed and the presence of caves increases the probability of meeting it.

Identification criteria : It is easily recognized by swimming and movements, with the pectoral fins waving to make the animal remain suspended from the bottom. The body is massive with dark tail and dorsal and anal fins edged with light. In the most common livery, moreover, there are light spots placed radially around the eye.

Complementary morphological description : Different liveries have been observed:

Standard livery : this is the most common livery, on a brown background and with light spots all over the body.
Clear livery : this livery, in which the body lightens below a line that connects the muzzle to the back of the dorsal fin, is characteristic of young adults who swim in open water.
Dark livery : the body is uniformly dark in color. This livery is related to the mood and is an indicator of aggression.
Dark 3-spot livery: unlike the previous livery, in this case 3 light spots are evident on the dorsal fin. This livery also appears to be related to aggression.
Silver streaks livery (male) : the radial spots around the eye, which turns white, are white-silver. The terminal area of ​​the tail and fins, instead of being dark, is gray. In addition, behind the head, there is a large clear spot and evident silver streaks on the sides. The background color tends more to black than brown. This is the livery of the large males who must defend their territory during the summer, which is the reproductive period.
Possible confusions: None, except with other groupers. In any case, the brown grouper has very particular dimensions and liveries.

Size : The grouper is a large fish, which can measure up to 150 cm. Usually, however, the specimens most commonly measure 80-100 cm.

Depth : The grouper frost lives between 10 and 50 meters deep. Younger specimens can also be encountered in more superficial waters. In any case, it goes up to 200 meters deep.

Distribution : The grouper has a very wide distribution area, ranging from the Mediterranean Sea to the Atlantic coasts: from the British Isles to South America (Brazil, Argentina, Uruguay) and from the western coasts of Africa to the Indian Ocean (Madagascar)

Living habits : Carnivorous fish, it is a great predator. It feeds on cephalopods, crustaceans and other fish. This leads her to be a curious animal, but also highly territorial. Due to fishing it is not uncommon for it to have shy behaviors which, however, give way to indifference within many protected areas where the animal does not feel threatened. In order not to alarm the grouper, in order to take photographs or to observe the animal closely, direct eye contact (eyes in the eyes) should be avoided when approaching.

Environments where it is possible to observe it : The brown grouper prefers rocky environments with shelters and cavities in which it can hide. The articulation of the seabed and the presence of caves increases the probability of meeting it.

Identification criteria : It is easily recognized by swimming and movements, with the pectoral fins waving to make the animal remain suspended from the bottom. The body is massive with dark tail and dorsal and anal fins edged with light. In the most common livery, moreover, there are light spots placed radially around the eye.

Complementary morphological description : Different liveries have been observed:

Standard livery : this is the most common livery, on a brown background and with light spots all over the body.
Clear livery : this livery, in which the body lightens below a line that connects the muzzle to the back of the dorsal fin, is characteristic of young adults who swim in open water.
Dark livery : the body is uniformly dark in color. This livery is related to the mood and is an indicator of aggression.
Dark 3-spot livery: unlike the previous livery, in this case 3 light spots are evident on the dorsal fin. This livery also appears to be related to aggression.
Silver streaks livery (male) : the radial spots around the eye, which turns white, are white-silver. The terminal area of ​​the tail and fins, instead of being dark, is gray. In addition, behind the head, there is a large clear spot and evident silver streaks on the sides. The background color tends more to black than brown. This is the livery of the large males who must defend their territory during the summer, which is the reproductive period.
Possible confusions: None, except with other groupers. In any case, the brown grouper has very particular dimensions and liveries.

Trivia and Observations : The life of a grouper can last up to 60 years. The grouper is a protogynous hermaphrodite, that is, the female becomes male at about twelve years old, which is why the largest animals are almost all male. Sexual maturity for females is reached at around 5 years of age.
According to somestudies, sexual inversion in Europe occurs between the ages of 14 and 17 at a size of around 80-90 cm. According to other studies, however, it occurs at88 cm and 12 years of ageor even earlier, between52 and 77 cm. In any case, theminimumfishingsizein Italy is 45 cm, therefore well below the sexual inversion dimension. In Sardinia theminimum catch size is 30 cm.

Epinephelus marginatus, the dusky grouper, the yellowbelly rock cod or yellowbelly grouper, is the best known grouper of the Mediterranean Sea and North Africa coast.

Description[edit]

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 the anal and caudal fins and also often pectoral fins have narrow white terminal bands; the pelvic fins are black towards their tips while the pectoral fins are dark reddish-brown or grey; the margin of spiny dorsal fin and basal part of the pectoral fins are often golden yellow in colour.^[4] There are eleven spines and 13-16 soft rays in the dorsal fin. This species can grow up to 150 cm in standard length but is more often 90 cm.^[5]Epinephelus marginatus in the Mediterranean

Distribution[edit]

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 the Cape of Good Hope, extending east into the south-western Indian Ocean, as far as southern Mozambique, with doubtful records from Madagascar and possibly Oman. It is found throughout the Mediterranean too. The second population occurs in the south western Atlantic off the coast of South America in southern Brazil, Uruguay and northern Argentina.^[1] In the eastern Atlantic it is not normally found further north than Portugal but there have been rare records from the Bay of Biscay and in the English Channel as far north as northern France, Great Britain and Ireland.^[6]

Habitat[edit]

Epinephelus marginatus is demersal, 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 of Poseidonia 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]

Biology[edit]

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 is molluscs, crustaceans and octopii but as they grow larger other fish form an increasingly important part of their diet, with reef fish being preferred.^[4][3]

E. marginatus is a protogynous 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,^[7] although most change sex when they are between 80 and 90 cm in total length.^[4] In some populations the presence of large female fish suggests that not all females change sex.^[7] 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 where E. marginatus traditionally gather to spawn include the Medes Islands Marine Reserve in Spain, off Lampedusa in Italy and Port-Cros National Park in France, all in the Mediterranean; fishermen in Brazil suspect there are aggregations off the coast of Santa Catarina but so far none has been definitely found.^[7] In the Mediterranean spawning lasts from June to September, mating is polygynous and the spawning clusters normally have seven females to each male. Off Brazil E. marginatus reproduces in the early summer, between November and December.^[8] 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]

Fishing[edit]

Epinephelus marginatus is a popular food fish and is caught across its range by commercial fishermen while large adult fish are targeted as trophies by spear-fishing,^[3] and is readily taken by anglers.^[2] 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 in aquaculture in Italy.^[9]

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).^[10]

Conservation[edit]

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, the International 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 in South Africa. In addition, a number of Marine Protected Areas have been established to protect the habitat of E. marginatus.^[1] In Turkey 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.^[11]