Argyrosomus regius. Maigre (meagre) is an Atlantic fish that in spite of its name is hardly meager; it can grow up to two metres long and weigh 40kg. Commonly known as the croaker in English for the loud grunting sound it makes, it can be confused with the wreckfish (cernier); you may see it on menus now, as the result of some success in farming it.
Other names for it in English are jewfish, shade-fish, sowa, kir, corvina, salmon-bass or stone bass.
Dos de maigre on a menu sounds like the back of a skinny person, but is actually the best part of this fish, the fillet.
Image by Mario Lepage