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Habitat and Distribution
Adults are associated with reefs and grassy bottoms, whereas juveniles are found in estuaries and seagrass beds. The species occurs in the western Atlantic from North Carolina to the Gulf of Mexico, with reports from Brazil.
Spawning season in the Gulf of Mexico
The spawning season for this species varies among regions and reports. The most common spawning season is from January through April with peak spawning in February and March. Spawning occurs from January through April off Campeche in Mexico. Off the west coast of Florida, pre-spawning aggregations occur during December and January, and spawning aggregations form and spawn during February and March. However, other studies report spawning in this region to occur over a wider season of December through May, with peak spawning during February to April.
Gag aggregate to spawn in the winter and early spring months on offshore reefs along the shelf edge at depths exceeding 40 m. Males tend to stay at or near offshore aggregation sites year round, whereas females occupy nearshore reefs during the non-spawning season. Females form pre-spawning aggregations at nearshore reefs that migrate long distances to join the males offshore. Spawning aggregation sites are comprised of tens to a few hundred fish and are highly predictable in time and space. Gag are protogynous hermaphrodites that form hierarchical spawning groups involving single-male, multiple females, and spawning likely occurs in pairs. Adults exhibit six or more ephemeral color patterns associated with sex, spawning behavior, and social status. The most conspicuous color patterns observed for Gag are those of the black-belly and black-back color phases. These color patterns are usually associated with males, but large females may also exhibit them. Gag are broadcast spawners with external fertilization.
Fishing Patterns in Relation to Spawning
On average, monthly commercial landings are greater during spawning months than non-spawning months. Recreational landings are greatest in May and are lowest during spawning months.
Management of Spawning Aggregations
The commercial fishery is managed under the IFQ program and there are no seasonal closures. Net and spearing gear are prohibited in federal waters for the commercial fishery. The recreational fishery in federal waters is managed by a daily catch limit of 2 that must fit within a total catch limit of 4 similar grouper. In state waters, catch limits mirror federal limits, or are sligtly less restrictive. The recreational fishery is closed Jan. 1 - May 31, which spans the entire spawning season. Madison Swanson, Steamboat Lumps and the Edges are closed year round. The minimum size is 22" TL for commercial and 24" for recreational.