The hookset and fighting a tarpon...
First, foremost and before we go any further, YOU MUST LEARN TO STRIP STRIKE!!!
The strip-strike is the only way to impart enough power to penetrate a tarpon's bony mouth with a fly. With tarpon, a good strip strike is executed in two steps. First, gently come tight to the fish which allows the hook point to find flesh and then power the hook home with the rod pointed directly at the fish by pulling on your line hand. The strike is an aggressive strip hence STRIP-STRIKE! There should be no bend in the rod! Only shift the rod tip after you feel the hook has been driven into the jaw. You'll know it if it's right. With no bend in the rod, you're connected directly to the hook via the line. A strip-strike also keeps the fly in the fish's strike zone if the hook misses its mark.
So...
LEARN TO STRIP-STRIKE!
If you try to set the hook as soon as the fly disappears in the mouth of the fish, you will simply pull the fly out of the tarpon's mouth. Strike only after you see the tarpon shut its mouth and turn its head. Again, strip strike with rod tip low and pointed at the fish. Then after the hook has been driven home, move the rod sideways in the opposite direction of the fish’s turn.
A set strike (commonly seen with trout anglers) employed by raising the rod tip to set the hook will never even come close to penetrating a tarpon's hard mouth. This set strike also pulls the fly completely out of the fish's strike zone.
A coming tight hookset common with bone fishermen (which is a less aggressive strip strike followed by a rod raise as the hook comes tight) does not drive the fly into the bony jaw of a tarpon.
So...
LEARN TO STRIP-STRIKE!
Set your drag before you cast to a fish, and once hooked, get all the spare line safely out through the guides. Always fight a tarpon on the reel... to do otherwise, invites disaster. Until the fish is on the reel, watch your line, not the fish. After getting the line on the reel, hold your rod parallel to the surface of the water and use the power of your twisting torso to put pressure on the fish with the rod's butt section.
This low angle not only generates much more power than a rod held high, but it also forces the fish to swim slightly deeper and minimizes the number of rejuvenating air gulps a tarpon can get.
One of the advantages of being an air breather (like a tarpon) is that air breathers can more rapidly recover from oxygen debt. This is because atmospheric air has a denser concentration of oxygen than water. This explains why tarpon roll during an extended fight. Tarpon thus have two sources of oxygen available to them during a fight. Their large gill surface area and their ability to breath air explains how tarpon are capable of such long extended fights. By not allowing a tarpon to reach the surface, you eliminate an important source of oxygen and you can tire out a tarpon much more quickly.
In addition, by keeping your rod low and twisting your torso, you can make a fish work harder by forcing it to swim in the opposite direction from the pull. Plus, the added drag from the line in the water will further tire the tarpon.
When a tarpon jumps, you should bow to him by thrusting your rod towards him. Remember the weight of a submerged tarpon is diminished by a huge amount. When he jumps he loses the buoyancy of the water and weighs what he actually weighs. When falling back to the ocean, his weight is increased by gravity. The tarpon can now easily break a leader if he falls on the line. The leader system will more likely hold up if the pressure is taken off during the jumps.
When fighting a tarpon, keep the fish off balance and do not let the fish rest and certainly not gulp air as previously discussed. Keep maximum pressure or "heat" on the fish at all times. You want to break the tarpon's spirit early in the fight and if you do, many times they will come more quickly to the boat and there is less chance of the hook pulling or working its way out. In addition, a quick conclusion to the battle does less harm to the fish which translates to a higher percentage of successful releases.
So, when fighting a tarpon, remember these FOUR things:
• Fight with the butt section of the rod. This may mean pointing the rod almost directly at the fish at times for greatest leverage.
• Fight the fish “down and dirty,” meaning low-angle, lateral pressure away from the fish’s direction of travel whenever possible. Keep his head underwater by holding the rod tip low.
• Bow to the fish when he jumps.
• Fight a tarpon aggressively. If they get the idea that they can do what they want, they will never give up. Put the heat on them from the beginning.