By Scotty Kyle

I am one of the most charismatic and well-known, not to mention massive and scary, fish in the world. I am a fish of myth and fantasy, but the scientific truth is almost as exciting as the legend. I am one of the biggest bony fish in the world. My scientific full name is Epinephelus itajara, but most people know me as the Goliath grouper. This is my story. 

We were the absolute lifetime target of spearfishers and recreational anglers, as well as a very important commercial species, but this combined pressure has led to our depletion. Recently, however, through improved management and protection by man, we are making a solid, though slow and localised, recovery. Let me tell you about my appearance and size, reproduction, daily routine and feeding habits, where to find and how to catch me, and debunk a myth or two.

Appearance and size: True to the name

My species is called the Goliath grouper, and we can indeed grow as large as our name implies. We have the solid, elongate body typical of groupers. Humans describe us as “robust”, because our girth can be substantial. Our colours are variable and change with size and age. Overall, we are a mottled-brown to grey, often with small dark spots on our flanks and fins. Our youngsters have several clear, thick, dark vertical bars down their bodies for camouflage. Small specimens often have distinctive yellowish fins with dark spots.

Mouth, teeth, and the suction strike

Our mouths are massive and armed with rows of small sharp, backward-curved teeth in our lower jaws. Our lower jaws protrude and, when hunting we surreptitiously approach prey and then, when close enough, rapidly and strongly open our mouths sucking in the helpless, unsuspecting prey. Our eyes are small, but we use all our senses, including our lateral lines, to locate and move towards prey, which we can find quite easily even in coloured water.

How big do we get?

Our size is open to much discussion, exaggeration and speculation. This is principally because most often when we are seen, killed or found dead there is no means to accurately weigh us. But we keep growing until we die, and can attain truly legendary dimensions. Human scientists estimate our maximum mass at about 455 kg (1 003 lbs.) with a greatest length of 2.5 metres (98 in.), but specimens of around 200 kilograms (440 lbs) are still common in some areas. 

My cousin, the giant grouper or brindle bass (Epenephelus lanceolatus) who seems to replace my species in much of the world, could be even bigger. We are similar in size, appearance, biology and habits, occupy the same niches. It’s not clear who of us is the largest grouper, the same human scientists estimate that my giant grouper cousins can attain up to 600 kg. (1 322 lbs) and about 3 metres (118 in.) in length, but exact comparisons are not possible as our ranges do not overlap. 

Slow growth and complicated sexual relationships 

If you ask me how a fish gets so big, in a word, the answer would be “slowly”. We are a slow-maturing species and generally attain sexual maturity when we are 4-6 years old and around one metre (39 in.) long. Our sex life is complex and not well understood, even by us. We mature mostly into active, functioning males for a few years and then many, or maybe all of us, morph into functioning females, or so I am told. Personally, I am about 1.5 metres long (59 in.) and am male but what the future holds is unknown to me. I have seen very large goliath groupers of both sexes and so there seems to be a degree of “plasticity” in our gender “condition” with no absolute “rules”.

Spawning migration, drifting egg, and an estuary nursery

My parents underwent a substantial offshore migration to meet up with others and, during a communal event in the dark of night, myriads of eggs were produced – including me. My egg drifted in the upper layers of the ocean, hatched, and I fed and grew and then, at a few centimetres in length and by means not yet fully understood by humans, I ended up in a large river estuary in Brazil. In estuaries there is abundant food and essential cover for the small fry like I then was to hide from the ever-present predators. 

I began life eating uninteresting but tasty floating zooplankton (animal plankton) and slowly became what is called an “ambush predator”. I first fed on small shrimps, fish and, in fact, almost anything I could fit into my mouth. Inedible items I spat out after investigation. Estuaries, particularly those with mangrove trees, contain incredible densities of tiny fish and invertebrates and are essential components of the life cycle of many species of fish and invertebrates.

Growing up: from estuary to ocean shallows, reefs, and deeper water

I lived alone, grew, and watched as other members of my species moved downstream and disappeared into the ocean. In turn I then felt an irresistible urge to move down the estuary and into the shallows of the ocean. There, I found places with good cover in which to hide and from which to ambush prey, and life was good. I spent many years slowly cruising around the reefs and rocky areas, growing all the time, and generally moving further offshore and into deeper waters. Some of my species, however, returned to, or even stayed in, shallow waters, particularly in muddy estuaries, and some took up permanent residence in harbours or shallow water shipwrecks.

A Goliath’s routine: feeding, hunting, occasionally socialising

Food is top priority in my daily life. I love my food and I am very good at finding and engulfing it. We are what some humans call “catholic” in our taste: we eat a wide variety of food items and these can change with age, stage, locality and availability. 

We mostly hunt at night and spend our days lurking in caves or against reef walls. At dusk we glide slowly out of cover and almost imperceptibly cover ground on the look-out for potential prey. We can travel a great distance from cover after dark and can really surprise unsuspecting fish, or even sport anglers. 

Dark is when lobsters and crabs venture out of hiding and these are among our favourite, tasty and crunchy. Fish that’s shoaling, fast-moving and alert, are not easy for us to approach but, as we love fish flesh, we concentrate on slow-moving species such as skates and rays. We have been seen eating small marine turtles, sea snakes or even swimming birds and we will try eating anything that looks tasty and is small enough to fit in our mouths.

When anglers “play” a fish, we sometimes play too

Any fish acting strangely attracts our attention and we will investigate it. A fish that an angler hooked and is “playing” behaves strangely enough for us, which occasionally results in surprises for humans. There are several harbours and piers where well-known members of my species reside. Some innocent angler may hook a fish and, as he reels it in, a goliath grouper engulfs it and slowly swims off, much to the dismay of the angler. Anglers in boats, too, sometimes see our massive bulk rise from the deep to engulf their fish just as it nears the surface. One of my cousins has several pieces of nylon dangling from his mouth because of repeatedly taking anglers’ fish.

Mostly solitary, occasionally aggregating: A Goliath’s social life

My species is mostly a solitary species and, as our movements are usually after dark, little is known of where we go and when. Groups of smallish members of my species are often seen around structures such as reefs and jetties but, when fully mature, we prefer our own company. Humans call us “highly territorial”, but they know of localities where aggregations of goliath grouper are seen each year and assume this is spawning related. I did hear a story from a cousin who had lived for years in an aquarium, that several large goliath groupers could live there in apparent harmony. 

A few tips for Davids: Where to find, how to catch a Goliath grouper, and why you shouldn’t

The Atlantic goliath grouper, as the human name implies, is found in the warmer areas of the Atlantic Ocean. On the western coast we can be found from northern Florida, south to Brazil and we are quite common in the Gulf of Mexico and parts of the Caribbean Sea. On the eastern side of the Atlantic, we can be found off Africa from Senegal to Congo, mostly in estuarine systems or around offshore islands with suitable reefs.

Depth range: The Goliath likes it shallow

Despite our impressive size, we tend to shun deep waters. Humans estimate our normal depth range as 1-50 metres (3-164 ft.) with a few specimens going down to 100 metres (328 ft.). This is probably due to our nocturnal habits and small eyes as, in deep waters, we can see very little.

If you insist on trying to catch one

Across most of our range, we are a protected species. But even where fishing is allowed it is not easy to land a large goliath grouper. To have a chance you need a strong “broomstick” spinning rod with an excellent quality reel plus very strong braid. Live bait like a medium-sized fish, especially stingrays, work well and can entice us to take a nibble. The trick, however, is to stop us retreating into our cave or wreck. 

We were also very popular with spearfishers, spearing “monster” specimens, but spearfishing my species has now been mostly stopped. There is little point in fishing for us as impressive photos are difficult to take and photos of dead fish now often elicit a negative response from many humans.

Myth busted: Goliath groupers do not eat humans!

That cousin I told you about shared an aquarium with a 50 kg (110 lbs.) shark. One night, feeling a bit peckish, he decided to eat it. In the morning, the human guards were most surprised to see the shark protruding from his mouth. Shortly after that he was released back into the ocean – as humans, who were not much larger than 50 kg, had been swimming with him and feeding him by hand and didn’t wish to end up with an item on his menu.

My cousin got lucky, as the worries of these humans were unfounded. Indeed, we are physically capable of eating humans and stories of this have been circulating for centuries, but they are false. We occasionally approach divers, but this is out of curiosity or in defence of our territory. There is absolutely no evidence of Goliath groupers ever approaching humans with an intent to harm them. 

The goliath returns: Fishing pressure and protection.  

We used to be a significant part of many commercial inshore catches. Our low and decreasing numbers, plus slow growth, have resulted, happily, in our being taken off the “allowable” species in many areas and countries. We are still locally important in the aquarium trade, both for “fishtanks” and large aquaria, but this is on a small scale. 

As already mentioned, across most of our range we are protected species. Landing a Goliath grouper in places such as Florida is prohibited and even taking my species out of the water for a photo is not allowed. This protection is helping us rebuild stocks and many humans now have opportunities to see and interact with us in the wild.

Historically, we had a bad relationship with humans, but a corner has been turned. Thousands of people now have opportunities to be impressed by our size and magnificence in our natural habitat and tourism around our species is growing.

My giant grouper cousin tells me that around Taiwan, for example, his species had been wiped out but now humans have bred them in captivity and re-established them in some areas. So, despite an unfortunate history of exploitation, our two species have moved to a position of partial mutual respect, benefit and support.

Next in ‘Life History of a Fish’

Life History of a Fish: Roosterfish

I am a tropical nearshore predator, most common around the Sea of Cortez, Baja California, and off the Pacific Coast of Costa Rica, Panama and Ecuador. I have a prominent dorsal fin, resembling a mohawk, and impudent manners, which is earned me the nickname the Punk of the Pacific, but most humans know me as Pez Gallo, or Roosterfish. CONTINUE READING