Close up image of a goliath grouper in south Florida.

Every now and again, we get some tourists that stop by the shop and ask us…

“Where do you guys going diving?”

To us, this may seem obvious…

The ocean, man!

But some people, locals and tourists alike, don’t realize how much life lies just 7 minutes east of our dive shop.

A bit south of Deerfield Beach, our hometown, Florida holds the world’s third largest barrier reef known as Florida Reef.

From the Florida Reef, a collection of reef systems spans the coast, running east and west.

In addition to reefs, South Florida also offers various artificial shipwrecks.

These wrecks provide a new dimension of life and opportunity for divers to experience.

One of the best phenomenons that occur annually on a prominent wreck in South Florida is the goliath grouper spawning season.

Goliath as their name depicts, are huge grouper who aggregate for reproduction purposes at the same wreck, at the same time each year.

These nearly 800 pound fish come together in crowds of 30-50 goliath grouper, reaching up to 100 at the M/V Castor wreck - truly a spectacle you won’t want to miss.

Learn more about goliath grouper and how you too can add this experience to your diving bucket list!

About the Goliath Grouper

The goliath grouper is the largest species of bony fish.

Goliath grouper, scientific name Epinephelus itajara, is also called Itajara in some regions, can grow to a length of 8.2 feet (2.5 meters) and can weigh up to 800 pounds (363 kilograms).

These car-sized fish are slow moving and are typically found in rocky reefs, wrecks, artificial reefs, and oil platforms.

Juvenile goliath groupers are known to hang out in mangroves, but tend to prefer structures as they mature.

Goliath grouper inhabit the waters from northern Florida south, all the way down and around to the Gulf of Mexico to the Caribbean and South America, including the coast of Brazil.

The lifespan of these fish is about 37 years, males reach maturity after six years, while the females take about eight years.

Interestingly enough, even though goliath grouper have many sets of teeth, they feed by swallowing their prey whole.

Since Goliaths are at the top of the food chain as the reef's natural predators, their populations are often low throughout most of the year unless it’s spawning season.

Another contributing factor to their population is their slow moving nature and routine predictability at certain sites.

Overfishing of goliath grouper between the 1970s and 1980s contributed to a huge population decline, endangering the species.

Prior to the overfishing, divers of the time report seeing hundreds of goliaths, sometimes looking like a solid wall due to the sheer amount of these giant fish.

Since these fish are slow moving, they’re easy to hunt, both spearfishing and with a rod and reel.

In 1990, goliath groupers were prohibited from harvesting in hopes to recoup the population.

In 1991, NOAA identified goliath grouper as an endangered species.

Thankfully, this move allowed the species to rebound and in 2004 NOAA transferred goliath grouper from the endangered species list to the species of concern list.

In 2006, goliath grouper was removed from the species of concern list, but still not legal to harvest.

There’s a lot of debate currently whether or not goliath grouper should be made available for harvesting given its rebound in population.

However, due to their slow moving nature and routine predictability at certain sites, others argue open harvest will create the same situation we saw in the 70’s and 80’s.

Other concerns include the fish’s high mercury content, which makes the fish toxic to eat.

Goliath Aggregation

Every year in August through October, goliath groupers congregate to spawn.

Spawning is how goliath grouper and lots of fish reproduce.

As mentioned above, goliath grouper move very slowly and tend to visit the same sites year after year.

This predictability is excellent for divers looking to spend some quality time with these gentle giants.

Goliath groupers love to hang around structures and artificial reefs, most notably wrecks.

These areas where they are known to congregate are vulnerable to fishermen.

A recent win for goliath grouper and divers who are looking to continue visiting these aggregations, was a decision made unanimously by FWC.

Thanks to a dedicated group of divers and conservationists, Palm Beach County Dive Association, FWC has marked off three popular dive sites as no-take zones.

These sites include MG-111/Warrior Reef in Jupiter, the Ana Cecilia/Mizpah wrecks in West Palm Beach, and the M/V Castor wreck in Boynton Beach.

This is especially important because these sites are the only spots that goliath grouper routinely visit for spawning.

Lucky for us, we regularly visit the M/V Castor, particularly during goliath grouper season.

M/V Castor

The M/V Castor is a very popular artificial reef in Boynton Beach, Florida.

Before becoming a popular dive site, the Castor was a Dutch freighter, built in 1970 when it was originally named the M/V Dorothee Bos.

It was designed as a dry cargo carrier to transport timber.

The ship’s name changed several times before being changed to M/V Castor.

In 1999, M/V Castor was seized by the U.S. Customs after the US Coast Guard found more than 10,000 pounds of cocaine on board.

On December 14, 2001, the M/V Castor was sunk as part of the Palm Beach Artificial Reef Program.

The M/V Castor is a 258 feet long, 37 feet wide freighter ship, with the bow pointing south.

The ship was originally sunk in 110 feet but has shifted to 118 feet over the years due to storms and hurricanes.

Hurricanes have broken up the ship over the years and the ship now lays on its starboard side with the deck sitting between 90-100 feet and the bow at 80 feet.

The Castor wreck is known to be one of the most vibrant and colorful wrecks on the Palm Beach coast.

In addition to its colorful corals, the M/V Castor is known for its goliath grouper presence.

Usually, about 10-30 goliath grouper live on this wreck at all times of the year.

The M/V Castor is a must-do wreck, but it’s important to keep in mind that the right conditions are needed to visit this site and enjoy it to its full potential.

Current is a huge factor when visiting the Castor, just something to keep in mind.

Thankfully for us, goliath grouper’s spawning season takes place during August - October, typically a great time to dive in South Florida as long as a hurricane isn’t brewing.

Join Us for the Goliath Grouper Aggregation

If you didn’t know much about goliath grouper before, we hope this post gets you a bit more familiar with these giant fish.

It’s truly incredible to watch these beautiful, very large fish slowly swim in front of you, giving you the moment to really take it in.

When you see various goliaths swimming around you…

It just feels surreal.

You can find out about our different dive charters by following the link below to our FareHarbor booking system.


Happy diving!

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