The mottled grouper has an oblong, compressed body which has a depth which is less than the length of its head, its standard length is 2.8 to 3.2 times its depth. The preopercle has a serrated margin with the serrations being enlarged at its angle, where there is a rounded lobe below an incision into the margin. The dorsal fin contains 11 spines and 15-17 soft rays while the anal fin contains 3 spines and 11-12 soft rays. The caudal fin is truncate in juveniles and subadults but it is concave in adults with a standard length of more than. They are usually reddish brown in colour, often mottled with black or pale grey spots and having a black streak above the upper jaw. The juveniles have a black saddle blotch on the caudal peduncle. This species has a maximum publishedtotal length of, although a more common total length is, while the maximum published weight is.
Distribution
The mottle grouper is found in the eastern Atlantic Ocean and parts of the Mediterraean Sea. In the eastern Atlantic it id found from southern Portugal and Spain, along the western coast of Africa as far south as Angola. It was formerly found in the southern Mediterranean from southern Spain and Morocco to Egypt and Israel but it has been expanding its range and is now found as far north as Provence in France and the Adriatic Sea. It is absent from the Black Sea and records from the Macaronesian Islands are misidentifications of Island grouper and records from Brazil are similarly misidentifications of the comb grouperM. acutirostris.
Habitat and biology
The mottled grouper is a demersal species which occurs over rocky reefs and adjacent sandy substrates as deep as. It tens to be commoner at shallower depths from in the eastern Mediterranean. It readily takes to artificial reefs such as shipwrecks off Sicily. Juveniles are usually found in shallower inshore waters. It feeds on molluscs and small fishes. It is a protogynous hermaphrodite, the transition from female to male happens when they are nine years oold and have attained a total length of. The females reach sexual maturity at a total length of about around four and five years of age. Spawning aggregations have been recorded off Israel, Senegal, Turkey and Corsica.
Parasites
As most fish, the mottled grouper harbours a variety of parasites. These include the diplectanid monogenean Pseudorhabdosynochus regius on the gills and the philometrid nematodePhilometra inexpectatata in the gonad.
