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Fun Facts about Atlantic Goliath Groupers

[Phylum: Chordata] [Class: Actinopterygii] [Order: Perciformes] [Family: Serranidae]

Imagine a grumpy looking fish with an average weight of 350 kilograms and a large, powerful body that measures well over two metres long (8 feet).

This segment contains fun facts and interesting information about the largest species of grouper fish in the Atlantic Ocean. We explain where these behemoths live, what they eat, and how they reproduce.

Grouper Fish Habitat & Geographical Range

The goliath grouper is one of the top level apex predators that inhabits most tropical and some temperate environments, especially:

The best place for divers to see the Atlantic goliath grouper is around rocky clusters and large muddy reef structures (natural or artificial).

Atlantic goliath groupers (scientific name Epinephelus itajara) are a fascinating species of fish. They are one of the largest reef-dwelling marine giants found anywhere in the Atlantic Ocean.

Pro Tip: They tend to thrive best in the sheltered shady areas of large sunken shipwrecks and underwater caves or ledges.

Atlantic Goliath Grouper Characteristics

In fact, all grouper species belong to a diverse group of ray-finned fishes known as "teleostei". In general, they are a stout fish with a broad head, menacing looking downturned mouth, razor sharp teeth, high set small eyes, and a heavy body.

Most of the species have dull body colouring, with various mottled patterns of green and brown. Others have bright and bold patterns, especially the red grouper (Epinephelus morio) that lives in deep water environments - down to depths approaching 180 metres (600 feet).

One of the most surprising grouper fish characteristics is being able to change their body colouration depending on their mood, activity, or surroundings.

Here's the thing:

Goliath groupers can vibrate their swim bladder to produce loud, low-frequency, booming sounds. The sounds are often used in territorial disputes or during the courtship ritual.

Goliath Groupers Size and Weight

So, how big are Atlantic goliath groupers? In fact, they start life as tiny larvae and measure only a few millimetres long. But, a full grown adult can reach a length of 2.5 metres long (8 feet) and weigh up to 363 kilograms.

These factors contribute to their general "slow and lazy" demeanour when swimming around the rocks and reefs of oceanic benthic zones.

Are Goliath Groupers Aggressive?

As a matter of fact, no they are not! But, due to their gigantic size, these carnivores often appear threatening and fearsome.

In truth, groupers are quite a timid fish. Even so, the males are big and brave enough to defend their territory if they feel threatened.

They are a surprisingly curious fish, and goliath groupers have very little fear of humans. As a consequence, scuba divers often get extremely close to them - which is great if you enjoy taking underwater photographs!

Pro Tip: Despite their imposing demeanour and gargantuan size, the Atlantic goliath grouper fish will not eat you and it is not the animal that kills most humans around the world!

What Do Grouper Fish Eat?

You don't need to get close to a grouper fish to see that it has an enormous mouth and some teeth. Yet, they use bony tooth plates at the back of the throat (pharynx) and their powerful jaws to crush prey to death - rather than biting it.

Using the width of their mouth, and the strong gill muscles, they create a suction system that draws food into their throat. In actual fact, they usually swallow food whole - instead of ripping pieces from it.

By and large, the favourite daily diet for most grouper species will include slow-moving fishes, along with a healthy supply of:

Interesting Fact: This feeding technique is so powerful, groupers often suck their victim into their mouth from a significant distance away. They actually use the same "sucking system" to shift and remove sandy substrate from their shelter.

How Do Groupers Reproduce?

Not only are grouper fish protogynous hermaphrodites (practice sequential hermaphroditism), but they also live in a monandric relationship.

Put another way:

They all function as females from birth. They transform into males as they grow older, and usually mate with only one sexual partner. Hence, groupers change gender from females to males during their early development or later in their adult life cycle.

Reaching sexual maturity can take as little as a few months or several years. The average grouper lifespan is thirty years in the wild. Yet, the goliath or "jewfish" specimen can grow to be fifty (50) years old. They are one of the longest-living fish species in the ecosystem.

This part is important:

Despite being mostly a solitary species, Atlantic goliath groupers congregate in large groups at selected locations and reef sites to spawn.

Thus, they release their eggs into the ocean as a group (a process called "collective spawning"). The juveniles will stay in protected mangroves and estuaries for about six (6) years.

Threats and Natural Predators

There are several reasons why the general populations of groupers worldwide is in serious decline. Typical threats to the long term survival include overfishing, habitat destruction (e.g. human development of mangrove habitats), and being:

To summarise, goliath groupers have a crucial role to play in helping to maintain the balance of reef ecosystems by controlling excessive populations of some prey species.

Important: Legislation was put in place in 1990 to protect Atlantic goliath groupers living in US waters. Catching and keeping them has been prohibited by law since then. Yet, in 2016 the IUCN Red List of Threatened Species cited the population status of the Atlantic goliath grouper as "Vulnerable" (VU).

Related Information and Help Guides

Note: The short video [1:57 seconds] presented by "Deep Marine Scenes" contains magnificent footage of the largest species of grouper in the Atlantic Ocean.

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