Yellowmouth Grouper

Mycteropreca insterstitialis has an elongate, robust and compressed body which is no deeper at the origin of the dorsal fin than it as the origin of the anal fin. It standard length is 3.0 to 3.4 times its depth. The preopercle is angular and has an obvious lobe at its angle, this lobe has enlarged serrations, there is a clear incision in the preopercle above this lobe. The dorsal fin contains 11 spines and 16-18 soft rays while the anal fin contains 3 spines and 10-12 soft rays. The dorsal fin has a pointed rear margin while the anal fin has a pointed margin at its lower posterior edge in adults. The caudal fin is rounded. The adults are pale brownish-grey in background colour marked with closely set small brown spots on the dorsal half of the head and body. In some fish the body is marked with irregular dark bars.

Mycteroperca interstitialis is found in the western Atlantic Ocean. Its distribution runs south along the coast of the United States from Cape Hatteras in North Carolina to the Bahamas, including Bermuda, and into the Gulf of Mexico, throughout the Caribbean Sea to Brazil. In Brazil it is found from Maranhão to Santa Catarina, including the islands of Trindade and Fernando de Noronha.

Mycteroperca interstitialis is an important species in the fisheries of Bermuda, the Gulf of Mexico, and throughout the Caribbean where it is caught with hook-and-line, traps, and spear. It is a scarce species and is not normally a primary target for fisheries which target M. bonaci and M. phenax. There have been reports of significant declines in many areas where there are large-scale grouper fisheries. Conservation measures which have been undertaken have not been effective and more measures are required and so the IUCN have classified it as Vulnerable.