Inhabiting shallow waters up to 150 feet (46 meters) deep, the goliath grouper prefers reef, rock and muddy bottoms. A solitary creature, the adult goliath grouper occupies a limited home range, normally including a place of safety such as a cave or ledge. In displays of territoriality, the goliath grouper will open its mouth and quiver its body. Sometimes, an audible ‘boom’ can be heard emanating from the fish, which stems from the contraction of its swim bladder. The goliath grouper is listed as critically endangered by the IUCN, mostly due to overfishing. The goliath grouper spawns in the same location year after year, making aggregation patterns easy to predict. Furthermore the goliath grouper is an easy target for spearfishermen given its large size, slowness, and lack of fear towards humans. Although it is a preferred fish for eating, studies have found that the levels of methylmercury in goliath groupers larger than 55 cm (22 inches) are higher than that recommended by United States governmental advisory criteria for human health.