The wreck of the MG-111 barge and the nearby pillars of Warrior Reef to the north aren’t very scenic as dive sites go– just a smooshed hull and a few tall vertical posts sunk 60 feet deep in the sand off Jupiter, FL. But for the opportunity to visit with some really large marine creatures– some of them the size of Mini Coopers –there’s no better place to visit in Florida right now.

Beginning with the August new moon, and likely through early October, scores of huge Goliath grouper hang around these motley artificial reefs getting to know one another and perpetuating their endangered species. They station themselves up- and down-current and inside the structures, occasionally making booming noises that sound like submerged bass drums. If you refrain from chasing them and remain stationary on the bottom, they may approach closely enough for you to shoot some amazing photos and video.

On my recent dive, I quit counting the gigantic fish at 50. They were cautious around me, but not spooky. One hovered inside the MG-111 about four feet away from me, opening and closing its wide mouth as I watched. As if that weren’t enough live entertainment, a five-foot Southern stingray glided by overhead. And at the Warrior Reef, a really large loggerhead turtle sat calmly in the sand while a small, tagged green turtle nibbled on sponges. All around them milled more Goliaths. To call it an epic dive is a vast understatement.

Florida State University research scientist Dr. Chris Koenig and his colleagues have identified some 20 Goliath grouper spawning sites off Florida’s Atlantic and Gulf coasts– including the one I visited. Most of them are wrecks and rocky outcroppings extending from Fort Myers south to the Dry Tortugas in the Gulf and from Jupiter south to Boynton Beach in the Atlantic. The Jupiter wrecks are the prime hot spots for viewing– easily accessible located only a few miles offshore.

Spawning, Koenig says, takes place late at night during new moon phases from August through October. Goliaths travel from as far as 300 miles away to join these aggregations and most depart when spawning is over, leaving a few stragglers year round. Koenig and colleagues have collected millions of Goliath eggs in their nets around the reproduction sites and hope someday to rear them so fish can be stocked in areas where they are heavily depleted.

The seasonal Goliath dive tours are an important economic driver for local businesses whose owners are vehement advocates for the gentle, mottled-brown fish. Goliaths have been protected from all harvest in Florida since 1990 when they were nearly wiped out by overfishing. In recent years, their recovery has prompted some hook-and-line and spear fishers to urge managers to re-open the fishery, but that’s not likely to happen anytime soon.

The most recent scientific stock assessment that might have led to a re-opening flunked peer review because it was inconclusive–lacking baseline information on Goliaths before they were hammered to near extinction in the 1970s and ’80s. Another potential obstacle to resuming harvest is that larger animals show high levels of mercury– a toxic heavy metal that can cause an array of health problems in humans who consume it. Koenig says Goliath mercury levels are so high that the fish themselves get sick and die of it. And, he says, the species is still threatened by poaching, recreational catch-and-release fishing, and bycatch in the bottom longline commercial shark fishery.

So, for right now, it seems the function of the Goliath grouper is to be the star of underwater safaris and video documentaries like the lions of the Serengeti. Take the plunge to see them before they split for the season.