The juveniles are greyish brown marked with large, dark grey roughly rectangular blotches on the upper part of the body and fins.

[2] The Gulf grouper is found in the eastern Pacific Ocean where it is endemic to Mexican waters from San Carlos, Baja California Sur south to Mazatlán.

According to the NOAA fisheries, Bahía Magdalena has the only known population of Gulf Groupers along the coast of the Baja California peninsula.

In the southern Gulf of California these aggregations cover areas larger than 1,000 square metres (11,000 sq ft).

[1] Gulf groupers at a young age tend to prey on different types of fish and invertebrates such as crabs and shrimp.

Reproduction period starts in April and ends in June where they gather in packs to form spawning areas that are typically in reefs.

The Gulf grouper is known as being protogynous hermaphroditic, which is when an organism matures as a female but later transitions into a male or vice versa.

[citation needed] The Gulf grouper aggregate into larger groups once a year to form spawning grounds for reproduction.

The Gulf grouper was first formally described as Epinephelus jordani in 1889 by the American academic Oliver Peebles Jenkins (1850–1935) and the ichthyologist Barton Warren Evermann (1853–1932) with the type locality given as Guaymas in the state of Sonora in western Mexico.

[1] The Gulf grouper population suffers due to toxic chemical runoff such as a gas spill that can greatly affect the water quality for the fish.

Scientists that are part of the NOAA have gone to implement different ways to improve the quality of the habitats that are meant to support the Gulf grouper.