The dusky grouper (Epinephelus marginatus Lowe, 1834) is a fish belonging to the family Serranidae. Epinephelus marginatus Cernia bruna
One of the largest migratory fish that divers may encounter in the Mediterranean and has been disappeared for many decades couse of spearfishing. For this reason it was essentially vanished from our shores as a result of overfishing. It a hermaphrodite species that changes sex during growth. The underwater fishing has on it a particularly detrimental effect, because the prey most desirable are the large specimens, which, in this species, are almost always male: the effect has been to make the reproduction extremely difficult.
In recent years things have improved and small specimens of groupers have reappeared near the rocky shores even in a few meters of water as we show in this short video.
Many serranid species are brightly colored, and many of the larger species are caught commercially for food. They are usually found over reefs, in tropical to subtropical waters along the coasts. Serranids are generally robust in form, with large mouths and small spines on the gill coverings. They typically have several rows of sharp teeth, usually with a pair of particularly large,canine-like teeth projecting from the lower jaw.
All serranids are carnivorous. Although some species, especially in the Anthiadinae subfamily, only feed on zooplankton, the majority feed on fish and crustaceans. They are typically ambush predators, hiding in cover on the reef and darting out to grab passing prey. Their bright colours are most likely a form of disruptive camouflage, similar to the stripes of a tiger.
Many species are protogynous hermaphrodites, meaning they start out as females and change sex to male later in life. They produce large quantities of eggs and their larvae are planktonic, generally at the mercy of ocean currents until they are ready to settle into adult populations. Typically groupers live in their lair, where they feel safe, and go out to get food and check the territory.