First, there are many different types of grouper found all over the world. Fortunately, most groupers have the same characteristics as far as habitat and behavior. Some popular groupers I like to hunt are gulf, leopard, and broomtail groupers. Gulf groupers are the bigger of the three, and can be well over a 100 pounds. They are considered rare, so keep that in mind before choosing to pull the trigger. These fish are delicious, and it makes hunting them especially rewarding.
Groupers love structure. Wrecks, drops offs with shelfs, and rocks are popular places to find them. Look in holes and under ledges were the bait fish gather. Groupers have big appetites so use that information to work for you. They can usually be found in water depths anywhere between 15' to 100'.
Year round inmost places, summer months will bring larger grouper in shallower. On the Pacific side of the U.S. and Mexico, groupers spawn from April-June time fame. During this time, larger numbers of grouper gather as part of the reproductive process.
One technique if the visibility is good that I like to do, is diving down on top of the fish in their blindspot. As I get closer to the fish, I glide the last 20' or so down until in range of the fish. If the visibility isn't good you may have to dive down on bait and wait on the bottom while grunting to attract a grouper. My gear setup all depends on water depth and the visibility that I’ll be hunting in for that area. The main thing about groupers is to stop them dead in their tracks. First for larger groupers, I prefer a big float that will stop them from going into deeper holes. Second, my floatline should have minimal stretch with the length being similar to the water depth I’ll be diving. Third, at a minimum I rig my spears with strong dyneema shooting line to avoid getting cut by reef or rocks. Coated cable is best but you can get into trouble with it if you get entangled. The shooting line length should be minimal, like 1 wrap, for poorer visibility spots.
Two reasons for this;
1. Puts immediate pressure on fish and stops it. Minimizing the amount of shooting line prevents the fish from running deeper and holding up in a hole.
2. Prevents entanglements. If you can only see 10’ or 15’ you don’t need 20’ of shooting line.
As for spear shafts, I prefer at least a 8mm or /5/16” or larger double flopper shaft. Again, I think that shooting a larger grouper with a flopper gives you more leverage and at times prevents the fish from holding up deep in a cave. Slip-tips around rocks just aren’t a great option and groupers have fairly tough flesh so tear outs are less of a factor. Your gun should be 3 bands at a minimum to penetrate a larger grouper at max range distance.
The shot placement.
Ideally, shooting a larger grouper straight in the face “unicorn style” prevents it from even going in a hole and increases the chance at stoning it.