Description:
The black grouper is a robust, oblong grouper that grows to a length of approximately 4.5 feet.  Body depth is less than the length of the head, which is convex in profile.  The lower jaw projects beyond the upper.  The jaws have well developed canine teeth.  Scales are large and ctenoid.  The preopercule is evenly rounded with no notch or lobe at the angle.  The nostrils are subequal.  The dorsal fin has 11 spines, with 15-17 soft rays and a deeply incised interspinous membrane.  The anal fin has 3 spines and 11 – 13 soft rays.  The pectoral fins have 16-17 rays.  Both the dorsal and anal fins are somewhat rounded at the margins, but the caudal fin is truncate. 

Body color varies greatly depending on hormonal levels and activity of the fish, but is typically light tan or olive to gray or dark brown marked irregularly with brassy or bronze colored blotches that are somewhat rectangular in shape.  Reticulations are separated by slightly bluish markings.  Spots may join to form horizontal streaks along the sides.  The soft dorsal, anal, and leading edge of pelvic fin all have dark margins, while the pectoral fin has a narrow orange margin. 

Habitat:
Adult black grouper prefer rock bottoms, drop-off walls, and coral reefs to depths of 32 – 98 feet.  In the eastern Gulf of Mexico, black groupers are found in waters deeper than 98 feet.  Smaller black grouper tend to be found in shallower waters.  Young juveniles are commonly encountered in seagrass beds in south Florida.  Most grouper species move to progressively deeper waters as they age, but can remain site-specific for long periods of time.  Black grouper have been observed to depths of 495 feet. 

Similar Species:
Black grouper are easily confused with 2 related species:  the gag, M. microlepis, and the yellowfin grouper, M. veneosa.  Black grouper are more easily distinguished from yellowfin grouper due to their having a straighter caudal fin and rows of rectangular spots and blotches, which tend to be larger and more defined than in the yellowfin grouper.  Black grouper also have a narrow, orange outer margin on the pectoral fins, while the yellowfin grouper has a wide, yellow pectoral margin. 

Small black grouper are difficult to distinguish from gag less than 15.5 inches because gag at that size are similar in overall coloration and marking pattern and have not yet developed the characteristic notch and rounded lobe at the angle of the preopercule.  Scale counts separate the black grouper from the gag;  the black grouper having 78-83 lateral line scales, while the gag has 88-96. 

Range:
Black grouper range from New England south through Bermuda, Florida, the Gulf of Mexico, the Bahamas, and the Caribbean, to southeastern Brazil.  Occurrences of this species north of the Carolinas are thought to be due to larval transport in the Gulf Stream current rather than from immigration of adults.

Black grouper are abundant in south Florida, the Florida Keys, Cuba and the Bahamas.  They are common on Florida's west coast, but are somewhat less common in east central Florida.