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Dusky grouper or Mediterranean Grouper is one of the most sought-after fish by underwater photographers for the colors of its livery and because as an adult it can reach considerable dimensions, on average over 60 kg in weight, for a length of 1.5 m. Epinephelus marginatus Cernia mediterranea Dusky Grouper
Epinephelus marginatus Cernia mediterranea Dusky Grouper intotheblue.it
Unfortunately, the quality of its meat and the “nobility” of the catch also make it one of the most fished by sport fishermen and divers. The Mediterranean Brown Grouper is therefore one of the species at risk and the IUCN red list classifies Epinephelus marginatus as a vulnerable species.
This video collects a series of encounters made in the summer of 2023 while free-diving, in two dens at about ten meters of depth. The Grouper is an extremely social species and in the summer it rises from the depths to populate the shallow depths of our coasts, so once it has chosen a safe hole it is easy to see it sharing in groups of some specimens even of different sizes and ages.
Epinephelus marginatus Cernia mediterranea Dusky Grouper intotheblue.it
In this video we even see four together in the same hole. What makes this species vulnerable and at risk is the very nature of this fish, in fact groupers are all born female! This fish is a protogynous hermaphrodite, which becomes male around twelve years of age. The large specimens are therefore all male.
Reproduction occurs during the summer period and the female that we could define as “alpha” within a group of other females, once reproductive maturity is reached, becomes male and tends to reproduce with the other specimens in the group that are still female.
Epinephelus marginatus Cernia mediterranea Dusky Grouper intotheblue.it
The specimens in this video are therefore all females as they are still small (maximum 40-50 cm) and therefore young. For this reason, spearfishermen “would be” their best custodians since freediving is the only type of fishing that allows you to select the fish and therefore let the “small” specimens live and then become males. Obviously, this does not apply to all other types of sport and professional fishing.
Unfortunately, however, we often see catches of less than 40 cm of minimum size and this is the main reason why the Grouper is becoming increasingly rare. Another factor that affects this is that this species has a swim bladder that is inflated with gas, and allows the fish to balance itself in the water just like a diver’s BCD (variable buoyancy compensator). Therefore, once caught by hooks and nets and brought to the surface, it tends to inflate due to the decrease in pressure, causing damage to the fish. For this reason, the practice of “Catch and release” with Groupers is completely impractical.
Epinephelus marginatus Cernia mediterranea Dusky Grouper intotheblue.it
The call for sustainable fishing is therefore a must for this species, which however, when it is not scared, allows freedivers to get very close to it, so we invite you to leave the spear gun and equip yourself with a video camera and torch. I guarantee that capturing a nice video and some nice photos will give the same satisfaction as killing a fish to satisfy your palate and belly.
Dusky grouper, Epinephelus marginatus (Lowe, 1834), is a fish belonging to the Serranidae family.
Description
Large in size, up to 140-150 centimeters for up to 60 kilograms of weight. Very long-lived (even 50 years with an estimated maximum age of 61 years). It is brown in color with lighter spots, tending to be darker in older specimens; typical are the light spots around the eye. The fins are also dark brown, with the exception of the margin: in young specimens it is light, a characteristic that is lost in adult males.
Epinephelus marginatus Cernia mediterranea Dusky Grouper intotheblue.it
Reproduction
The fish is a protogynous hermaphrodite, which becomes male around twelve years of age. Large specimens are therefore all male. Reproduction occurs during the summer.
Diet
It feeds mainly on molluscs, crustaceans and other fish.
Related species
In the Mediterranean Sea there are other species of Epinephelus in addition to E. marginatus such as E. aeneus, E. costae, E. caninus. E. marginatus can be distinguished from the others by the convexly rounded edge of the caudal fin, by the light lateral stripes on the head and by the typically brown color, more gray in the other species. The family of Mediterranean groupers is however completed by two other species of groupers of a different genus: Polyprion americanus and Mycteroperca rubra, known respectively as bottom grouper and red grouper.
https://it.wikipedia.org/wiki/Epinephelus_marginatus
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