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Size
8 feet (2.5 m) -
Diet
Fish, sharks, juvenile sea turtles and crustaceans -
Range
Indo-Pacific -
Habitat
Tropical shallow reefs, caves, wrecks and estuaries
Physical Characteristics
Size
- Largest of all coral reef-dwelling bony fish.
- Common length up to 8 feet (2.5 m)
- One of the largest recorded was 9.8 feet (3 m) and weighed more than 882 lbs. (400 kg).
Color
- Juvenile giant grouper are bright yellow with large, irregular black or dark brown bars
- As adults, irregular patterns break up and their coloring becomes a muted, mottled olive-gray.
Body Composition
- Has a very large mouth that expands and protrudes to create a strong suction to draw in prey.
- Mouth has at least seven rows of teeth on the middle of the lower jaw.
- The giant grouper’s eyes function effectively in dim light, which gives it an advantage over its prey during dawn and dusk feeding times.
- Eyes also rotate so grouper can see approaching prey without moving its head.
Animal Fun Fact
Because it is long lived and late to reproduce, the giant grouper is highly susceptible to overfishing. Fishermen generally target larger individuals, meaning that, frequently, too many breeding specimens are removed from a population for it to sustain itself.
Diet / Feeding
Diet
- Consists of fish, sharks, juvenile sea turtles and crustaceans, including spiny lobster and mud crabs.
Feeding Behaviors
- Ambush predator that lies in wait while hiding in holes, crevices and reef overhangs.
- Swallows food whole.
- Occupies the upper end of the food chain:
- Few reside in each area; few found on any one reef.
- Replacing older fish with a young individual takes many years.
Range / Habitat
- Occurs in the Indo-Pacific from the Red Sea to Algoa Bay, South Africa through the Hawaiian and Pitcairn islands and south to Australia.
- Found in tropical shallow reefs, caves, wrecks and estuaries commonly to 164 feet (50 m) deep. Full depth range is 13-328 feet (4-100 m).
- Most widely distributed of all the grouper species, but tends to be solitary with a “home” that they typically stay in.
- Juveniles tend to stay in sheltered areas like under ledges. Adults are found more offshore around piers, bridges, and wrecks.
Reproduction & Growth
- Protogynous hermaphrodite; starts out life as a female and can later change gender to become male.
- Does not reach sexual maturity until it is about 20 years old. Fishing usually removes the largest, and therefore oldest, fish first.
- Slow-growing and lives up to more than 50 years.
Conservation Status
- “Data Deficient” on IUCN Red List.
- The population is thought to be declining 20 percent rate every ten years.
- Populations of this species have been drastically reduced worldwide due to overfishing but long-term quantitative data are not available across a large portion of its range.
Additional Information
- Other common names for this species are “Queensland grouper” and “brindle bass.”
Sources
- Encyclopedia of Fishes. 2nd Edition, pgs. 195 -199
- Fishes of the Great Barrier Reef. Randall, J. E., pg. 109
- Fishes of the Tropical Eastern Pacific. Allen, G. R., pg. 106
- Reef Fish. Thresher, R. E., pgs. 153 -155
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iucnredlist.org
