Filmed in Palm Beach Florida by Ramon Llaneza. During reproduction (immediately after the full moons between June and December), they come together in groups of at least 100 individuals. These groups are known as spawning aggregations, and they form at relatively few places throughout the species’ range. Individual Atlantic Goliath Groupers likely travel many miles to reach their preferred spawning sites and form part of the spawning aggregation. At these sites, the groupers reproduce by a method known as broadcast spawning, where females release eggs and several males release sperm into the water column above deep reefs all at the same time. This method increases the likelihood that eggs will become successfully fertilized and that fertilized eggs will not be eaten by egg predators on the reef surface. The giant of the grouper family, the goliath has brown or yellow mottling with small black spots on the head and fins, a large mouth with jawbones that extend well past its small eyes, and a rounded tail. It also has five dark body bands or stripes that are most visible on young goliath.
Goliath grouper populations dramatically declined throughout their range during the 1970s and 1980s due to increased fishing pressure from commercial and recreational fishers and divers. Prohibited species receive greater protection to ensure continued health. This led to a prohibition from harvest in U.S. waters in 1990.
Goliath grouper populations have substantially recovered since the harvest prohibition took effect. There have been increases in abundance in certain areas, and the distribution of goliath grouper populations has extended into areas of its former range throughout Florida, including the Big Bend and Panhandle regions.
However, it is not clear as to when they may fully recover and when harvest restrictions could be relaxed.
Goliath grouper is the largest of the western north Atlantic groupers. This giant can reach 800 pounds (455 kg) and over 8 feet (2 meters) in length. The Florida record is a 680-pound goliath grouper caught off Fernandina Beach in 1961. The species had been targeted both commercially and recreationally since at least the late 1800s.
Goliath grouper are extremely vulnerable to overfishing due to a combination of life history traits such as slow growth, long life, late sexual maturity, strong site fidelity and the formation of spawning aggregations.
When not feeding or spawning, adult goliath groupers are generally solitary, sedentary and territorial. Before the goliath grouper reaches full-size it is preyed upon by barracuda, king mackerel and moray eels, as well as sandbar and hammerhead sharks. Once fully grown, humans and large sharks are the goliath grouper's only predators.
Goliath grouper are opportunistic predators and feed mostly on slow-moving, bottom-associated species. Calico crabs make up the majority of their diet, with other invertebrate species and fish filling in the rest. Goliath grouper will occasionally feed on fish that are struggling on a fishing line, but they have not been shown to actively hunt down fast, free swimming fish such as snappers and groupers. Prey is ambushed, caught by a rapid expansion and opening of the mouth that allows prey to be sucked in and swallowed whole.
Goliath grouper were found in tropical and subtropical waters of the Atlantic Ocean, both coasts of Florida and from the Gulf of Mexico down to the coasts of Brazil and the Caribbean.
In waters off Florida, young goliath grouper spend up to 5-6 years in mangrove habitat, particularly in the Ten Thousand Islands area off southwest Florida, which seems to be its center of abundance and may serve as critical nursery habitat. Because mangroves serve as important juvenile habitat for these fish, their loss could affect population recovery even if reproductive levels of adult fish are high. As they grow, goliath grouper move to shallow reefs, eventually joining adult populations offshore on shallow artificial and natural reefs. Adults seem to prefer habitat with overhangs, bridges, piers and shipwrecks.
Goliath grouper are relatively long-lived, with a maximum known age to be at least 37 years old. However, some scientists estimate that these fish may have the ability to live over 50 or even 100 years. Reproductive maturity first occurs in fish 5 or 6 years of age (about 36 inches in length) due to their slow growth rate. Males mature at a smaller size (about 42 inches) and slightly younger age than females. Females first mature at 6-7 years of age and 47-53 inches in length. Goliath grouper have been known to form spawning groups of 100 individuals or more. These groups occur at consistent sites such as wrecks, rock ledges and isolated patch reefs during July, August and September. In southwest Florida, presumed courtship behavior has been observed during the full moons in August and September.