Patrick - I'm a certified SCUBA diver with hundreds of dives logged around the world. Spear fishing for blackfish or grouper or similar is one thing. Tying into a multi-hundred pound tuna is another.
I was on a dive boat out of VA beach a few years ago when a school a
big amberjacks showed up. One guy jumped in with his spear gun and harpooned one. It nearly dragged him out to sea! Even when they did get him and the fish on the deck everyone had to pound on the thing to subdue it! (it was a very caveman-like scene! wish I had a camcorder)
Free diving is much more than just how long you can hold your breath under water. In some ways it's even riskier than SCUBA since you don't have an air supply. There are all kinds of risks: Air embolism, shallow water blackout, lung injuries, just to name a few. These guys who free dive for tuna are highly trained and disciplined athletes. Thier bodies are heavily conditioned for endurance w/o O2. And some do, unfortunatley, get injured or worse. You don't hear very much about them.
Be careful!
ps - It's not a record nor the largest I've taken but it sure beat the heck out of me!
[img=http://www.oceanviewhost.com/fishing/viking_tuna_jf265_anf.jpg]