Thud. Thud. Startle an unsuspecting goliath grouper and you might hear a deep, booming bark emitted from the swim bladder of the largest grouper in the Atlantic. Alarming noises aside, divers have the chance to swim alongside these majestic marine mammoths — Epinephelus itajara can grow to be 8 feet and 800 pounds — that are considered critically endangered. For an eye-and ear-opening experience, head to one of the shipwrecks off Jupiter, Florida, where spawning aggregations of 60 or more grouper can be found in season. And don’t be shocked if you hear — or feel — a boom.

When to go: August through September

Where to go: Jupiter Dive Center

Wreck of a Good Time

These Florida wrecks give you the chance to see grouper, a bit of history and more.

All the doors and portholes were removed before Mizpah was sunk to a maximum depth of 90 feet, so you’ll be able to see grouper, eagle rays and oysters in plenty of light.

Split in two pieces by Hurricane Georges in 1998 — the sections are about 100 feet apart — the Eagle offers divers double the fun, and the chance to see tarpon and grouper at 70 to 110 feet.

A freighter (Zion Train), a tanker (Esso Bonaire III) and a barge (Miss Jenny) make up the Wreck Trek, giving advanced divers — you’ll deal with current in about 100 feet of water — the chance to see three shipwrecks, along with spawning goliath grouper, moray eels and turtles, all in a one- or two-tank dive.