Description: Brownish gray in color with dark worm-like markings on sides; strong serrated spur at bottom margin of preopercle, less noticeable in large specimens; fins dark, with anal and caudal having white margin. Often confused with black grouper; most noticeable differences are brassy spots on black grouper; tail of gag is slightly concave, black is square; gag has white margin on anal and caudal fins, black does not; under 10 pounds, gag's spur on preopercle is distinctive, where black is gently rounded.

Similar fish: Black grouper, M. bonaci; Yellowfin grouper, M. venenosa; other grouper.

Where found: adults offshore over rocks and reefs; juveniles occur in seagrass beds inshore.

Size: common to 25 pounds

Remarks: forms spawning aggregations in water no shallower than 120 feet in Middle Grounds area, January through March; current research to identify similar aggregations off the Atlantic coast is ongoing. Young gags are predominantly female, transforming into males as they grow larger; feeds on fish and squid.