Goliath Grouper

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Goliath Grouper

Goliath grouper are a mostly quiet, mostly gentle behemoth that can be found in rocky shores and in shipwrecks. Once a prized game fish, it is now legal only to catch and release the giants. Divers often find them fascinating and will approach the languid fish as they guard their territories. This usually results only in a few nice pictures and an interesting story, but the fish – which can be four times larger than a human – should be treated with respect and caution.


Content List

1. Scientific & Common Names

2. Characteristics

a. Breeding

b. Behavior

3. History

4. Present Status

5. References


Scientific & Common Names

Kingdom - Animalia

Phylum - Chordata

Class - Actinopterygii

Order - Perciformes

Family - Serranidae

Genus – Epinephelus

Species – itajara

Common Names – Goliath grouper, giant seabass, black bass, jewfish (the name, though once common, was deemed culturally insensitive and the use has been mostly discontinued)


Characteristics

An exceptionally large fish, the Goliath grouper can reach sizes of over eight feet and eight hundred pounds, with an average size about half that. The thick, slow moving fish has a mottled, earth tone coloration with lighter stripes running vertically and rounded pectoral and caudal fins. They can live from 30-50 years, but the current average is believed to be 9-15. They have several rows of teeth in their lower jaw and faintly defined canines, marking a difference from other Atlantic grouper.


Breeding

The Goliaths, normally notorious homebodies, will travel up to several hundred miles for their summer spawning. Anywhere from a few dozen to a hundred individuals will congregate in shallow water where eggs and sperm are then released. After fertilization, the eggs float on the water currents until the larvae hatch. With extremely elongated pelvic and dorsal fins, the planktonic larvae are vaguely kite shaped but they transform into juveniles that resemble adults in a few weeks. The juvenile will move to sheltered areas like mangroves or estuaries until they mature. While it has not been confirmed with Goliaths, many grouper species are protogynous hermaphrodites, where they first mature as females and some then transition to males. Males become sexually mature at 4-6 years of age and females at 6-7, which is when most will emigrate from their juvenile territories into the coastal waters.


Behavior

Goliath grouper can be found in shallow, coastal areas in the warmer waters of the Atlantic, and a small portion of the eastern Pacific, although that is a separate species from the Atlantic population (Epinephelus quinquefasciatus). In the Atlantic, it can be found from Florida to the southern reaches of Brazil, including the Gulf of Mexico and the Caribbean. There are also populations on the western African coast possibly as far north as Senegal and the Congo to the south. They can be found at depths up to 150 feet and they prefer shallower, rocky areas. Rare for a grouper, they can also be found in brackish waters with the juveniles preferring mangroves and estuaries. They especially like caves, or defensible areas such as ship wrecks and they will defend their territory. Goliaths are even capable of emitting an audible grunting sound from their air bladders that acts as a warning. While they can eat anything they can fit into their large mouths, including sharks and young sea turtles, about half of their diet consists of crustaceans, especially crabs.


History

Fossil records dating from the upper Miocene show an immediate ancestor of the modern day Goliath grouper that is nearly identical. The minor genetic differences between the Pacific and Atlantic Goliaths would indicate that there has been slight change in the species over millennia. Little is known about them before the late 1800’s, when they became targets of organized fishing, but their numbers have plummeted at least 80% since then.


Present status

A highly sought after game fish, Goliath grouper are very slow developing fish and they are decidedly susceptible to overfishing. There have been strict controls in the US since 1990 and the Caribbean since 1993, but the fish is listed as critically endangered by the International Union for the Conservation of Nature (IUCN) and will take years to recover, even with no legal fishing. The populations in south Florida seem to be recovering, but the controls remain in place in the hopes that the population will spread. The other threat to the fish is mercury - found in nearly all marine animals - it is found in its highest concentration in top tier predators and long lived animals, both of which describe Goliaths. Many adults have been found with lesions in their livers from the pollution, and development of juvenile may be compromised by the neurotoxin.


References

Florida Museum of Natural History: Ichthyology

Mercury Poisoning: The Undiagnosed Epidemic by David Hammond

A Field Guide to Coastal Fishes: From Maine to Texas by Valerie A. Kells, Kent Carpenter

Synopsis of biological data on the Nassau grouper, Epinephelus striatus (Bloch, 1792), and the jewfish, E. itajara (Lichtenstein, 1822) by Yvonne Sadovy

Species Profiles: Life Histories and Environmental Requirements of Coastal Fishes and Invertebrates (South Florida): Black, Red and Nassau Groupers by Darryl E. Jory

Mortality Rates of Snappers and Groupers by Stephen Ralston, NPAA

NOAA – National Oceanographic and Atmospheric Administration

How many species of goliath grouper are there? Cryptic genetic divergence in a threatened marine fish and the resurrection of a geopolitical species by: M. T. Craig, R. T. Graham, R. A. Torres, J. R. Hyde, M. O. Freitas, B. P. Ferreira, M. Hostim-Silva, L. C. Gerhardinger, A. A. Bertoncini, D. R. Robertson