Vet Craft Sport Fishing

Terminal Tackle for Tuna Chunking
by Captain Harvey Yenkinson

The radio crackles at the end of the tuna fishing day, as the sun lowers in the summer sky. One fisherman reports," We were 3 for 7 today." His friend jumps in, " we went 2 for 11, lost alot of fish." A third pipes in, "we hooked up 5 and landed them all."

Such talk is common place among tuna chunkers, different captains reporting different success ratios. Compared to white marlin fishing, tuna fishing allows alot higher landing percentage, but still many fish are lost. Tuna are said to consume more food per pound of body weight than any other large pelagic fish in the ocean making them voracious feeders. Interestingly their prey has the smallest prey size/ predator size ratio (some large ocean mammals like whales also feed like that). Tuna have a very small mouth considerring their body mass, and the gape of their mouth being proportionately small means they consume bait less than 10 % of their own body size. The main food source for bluefin tuna are sand eels, a minute creature considerring the massive size of the tuna that frequent the inshore lumps that we fish for tuna. Yellowfin too consume small creatures, their diet consisting mostly of squid and small fish such as tinker mackerel. Tuna need to feed at fast speeds to enable them to catch their prey in such a small mouth and most baits hit are thought to be at speeds in excess of 20 knots! Tuna have tiny teeth in their mouths, used to enable them to grasp food, not to mouth or bite off a bait like a shark. Tuna swallow their baits almost immediately after they engulf them, to quickly make way for the next bait available.

Tuna have large eyes which requires good bait presentation and proper leader material. Yellowfin tuna appear to have better eyesight then bluefin, enabling yellowfin to be much more prolific night feeders than bluefin. Bluefin fishing usually is at its best just before sunrise, as the sky just begins to lighten, and continues through the day. Yellowfin are caught chunking inshore and canyons both day and night and are generally much more leader shy than bluefin.

Using this knowledge of tuna in combination with proper equipment can increase you hookup percentages.

Rods, Reels, And Fishing Line

Everybody has different preferences for fishing tackle. Large tuna can be caught on very light tackle if done properly. I believe what is important is not which tackle you use, but what condition it is in, and how you match the different components to your fishing style. Keep in mind too, that on very large fish, you may have to get off the ball (release your anchor rope from the boat, tying the end to a floating buoy). Your reel must have a good working smooth drag, so as not to hang up and inadvertently increase your drag pressure. Conventional wisdom is to set your drag to 1/3 to 1/4 of your line strength. I would advise you stay closer to 1/4 strength or less as you will find you will lose less fish when your drag settings are light. Skilled anglers use light drag settings and add a little drag as needed by using their thumbs to put additional pressure on the spool of the reel. This is a skill that is acquired by many hours of fishing for large fish, and is not an exact science.

Tuna love to find the weak link in your tackle. Fishing line or leader that is frayed or that has a knick in it, swivels that have been used for too many fish, or knots that are poorly tied may all survive a light drag, but won't survive a tight or uneven drag. Some people don't like to fish with light drags because it takes longer to get a fish to the boat. My experience is that tuna make an initial run that seems to last a similar amount of time whether you fish with heavy drags or light. If the tuna doesn't spool you on the intial run, you have a reasonably good chance of capturing the fish, moving the boat if you must. (Some large tuna can spool a reel on their initial run. Once I had a tuna spool an International 50 wide with 80 pound test and 23 pounds of drag in about 30 seconds). The other benefit of a light drag has to do with how much tissue the hook has a bite on in the tunas mouth. This is the main reason for a pulled hook. If the hook only has grabbed a small amount of tissue, a tight drag will pull the hook out of a tunas mouth whereas a lighter drag may not dislodge the hook. Many offshore fishermen have had the experience of gaffing a tuna, dropping it onto the deck and have the hook dislodge on the deck. One hard pull would have lost the fish. Keep in mind that during a long battle, the hole created in the tunas mouth widens, and keeping slack out of the line becomes even more important as the battle lengthens.


The big discussion about hooks when tuna fishing is whether to use circle hooks or conventional "j" hooks. Circle hooks were designed for commercial longline fishermen to enable a fish to be hooked soicly and not lost on an unattended fishing line. Circle hooks have the advantage of hooking a fish in the corner of its mouth, and although probably more fish are missed, hookups, once accomplished, are rarely lost as it is hard for a fish to dislodge a hook in this position of its mouth. Also this portion of the fishes anatomy is not likely to tear, whereas gut or throat embedded hooks, have a greater chance of pulling free. It is a misnomer that circle hooks always imbed in the corner of the jaw, as anyone who fishes with them will tell you that they have occasionally gut hooked tuna with this kind of hook.

Friends of mine who fish commercially for giant bluefin have gotten away from circle hooks because of the lower hookup percentage. If one holds both styles of hooks in your hand, logic would dictate that a conventional hook would lodge in the fish a greater percent of the time. Circle hooks are very forgiving of angler skill as a slack line will less likely lead to a lost fish. Tuna are notorious for making a run away from the boat, then charging straight back towards the boat. Unskilled anglers assume they have lost the fish, while skilled anglers are reeling as fast as they can to remove the slack line! Another advantage of circle hooks is that they limit the chaffing of leader material, as the leader is not within the tunas mouth, abrading on their tiny but sharp teeth. Tuna are sometimes lost after a lengthy battle, as the teeth finally abrade the leader to the point of breakage. The proper technique for fishing with circle hooks is to leave a minimal amount of drag on the line, just enough to prevent a backlash. After a bait is taken, advance the drag as the run begins, allowing the tuna to turn at an angle from the boat, allowing the hook to set in the corner of the jaw. I personally prefer conventional hooks unless I am going to release the tuna we catch. Opinions vary, with different captains having better luck with certain hooks, but my experience is that you will have a better hookup percentage with conventional hooks. The proper way to fish conventional hooks is to keep the drags half way up to strike, keeping a good amount of tension preset on the line. As the tuna swallows the bait at high speed the hook is pulled free of the bait and sets in the tunas stomach, throat, or mouth, all happenning in a fraction of a second! Fishing in free spool with conventional hooks will yield a lower percentage hookup ratio as the tuna may dislodge the bait if it feels the tension, before the hook has a chance to set. This is the reason for so called "run offs" and can be avoided by keeping drag set on the baits. When I first started to tuna chunk, I was amazed at how small the hooks were for such a large fish. The upside to small hooks is that they let the baits sink more naturally if free spooling out line and are easy to hide inside the bait. The downside of small hooks is that they take a smaller bite of tissue, the amount of tissue grabbed is limited by the distance between the point and shaft of the hook. I use Eagle claw tuna hooks when I fish and may use hooks as large as 9/0 to get a better bite of tissue, so less hooks are pulled free. If the hooks aren't sharp or have been used before, I will touch them up with a file. Once a hook can penetrate the tissue, it can grab ahold, but a dull hook point may be completely pulled out of the tunas mouth, and the tuna is never hooked up.


The benefit of swivels is to keep baits from spinning. The downside of swivels is that it makes for two more knots that can fail. I like to use swivels of 150 pounds, perferring the new (Spro) titanium ones, due to their small size. I do not like to use smaller swivels not because of the poundage rating, but because the narrow diameter of the metal in the smaller swivels can cut the line under tension. Baits can be fished without swivels, tying the hook directly to the fishing line. Baits that are being free spooled back into the chunk trail, are not likely to spin, as are dead sticked baits.


Knots are always a subject of interesting discussion and I have employed many types over the years. I am now down to two knots when tying tuna tackle: improved clinch knot and palomar. Both are very reliable knots, easy to tie, and reduce the breaking strength of the line very little. If I were to use one knot only it would be the palomar. This amazingly simple knot is easy to tie in low light conditions, hard to tie wrong, and has mimimal effect on reducing line/leader strength. I do not like to snell hooks for tuna fishing as the snell can creep up into the eye of the hook, and the sharp edge of the eye of the hook can cut the line. If you like to snell hooks, check the edge of the eye to see if it is sharp, welded eyes eliminate that problem.

Leader Material

Most discussions of tuna chunking end up being about what leader material was employed. It is interesting that early in the morning when the bluefin are biting aggressively, I believe you could catch them on a piece of rope! Most years, when fishing shark tournaments in June, someone will catch a bluefin on a wire leader. Early morning bluefin are not leader shy on most days. When fishing for larger bluefin around sunrise we have caught them on 150 pound Ande leader. However, due to not wanting to change leaders too much as the action can be fast and furious, we generally use 80 pound fluorocarbon as our starting leader material.

My thoughts on fluorocarbon are that it is surely less visible than monofilament, but maybe only 50-60% less visible. Hold a piece of 80 pound monofilament, and 80 pound fluorocarbon in the water side by side, and you will see what I mean. Certain brands like Momoi are clearer in appearance, and in my opinion less visible then cloudier looking lines. The commonly held belief (and advertisement) that fluorcarbon is "invisible" is just not true. I use fluorocarbon because it is less visible to the tuna. We will switch to lighter strength leaders if fish are in the area and not taking our baits. If boats around you are hooking up, try dropping down in leader size, and the bite can dramatically improve for you. If you are worried about leader abrasion in the tuna's mouth, a mouse trap rig is easy to hide by making a slit in the side of the butterfish.

Importantly if switching to 20 or 30 pound leader, remember to adjust the drag on your reel according, or just fish with lighter equipment, which is what I do. When fishing light tackle or light leaders, anglers need to remember all the factors that are putting tension (drag) on the leader. The drag pressure can be tested with a scale at the dock, but other factors take over as a fish is played. The initial strike of a tuna instaneously puts more tension on the line, until the drag starts to allow line to be released. As less line is present on the reel, due to laws of physics, the drag increases as the line peels off the reel. An experienced angler will pull back on the strike lever as the line peels off a reel, though it is tempting to do the opposite. Also keep in mind that a belly of line pulling through the water also adds to the tension on the leader. A good rule of thumb is to error on the side of the drag setting being too light when fishing light leaders.

Testing Your Terminal Tackle

I cannot stress how important it is to test your system before you fish with it. Every leader set up I use gets prestressed before I allow it to be used for fishing. I put my hook in a stable eyelet on my boat, wrap the line in my gloved hand and put the approximate appropriate amount of tension on the line for the leader material I am using. A scale can be used for more perfect assessment. Sometimes for reasons I cannot even see, a leader will break, and I am alot happier having this happen at the dock then at the fishing grounds. Use caution when testing your terminal gear. When a leader does break, the hook may go flying towards you, so try to pull the leader away from your face, and use protective eye cover.

Bait Rigging

Conventional bait rigging involves hiding the hook in the bait, usually butterfish, with the hook point barely protruding. Hooks poorly placed in the bait not allowing the hook to pull free once tension occurs on the line, can cause a missed fish. Fishing with live baits such as spot, allows a more exposed hook placement. Interestingly, due to tunas preference for small baits, minnows or eels can be an effective bait as well, and allows an excellent hookup percentage. Another bait very prevalent on the inshore waters are croakers, and the smaller ones that I have saved in my livewell at the dock (made from a 55 gallon plastic container drilled with many holes, and floated with a "noodle" collar) have caught tuna for me as well.

Angling and Gaffing

The basic causes for a bait being taken and a fish not being landed can sometimes be bad angling technique. Not keeping constant tension on the fish is a common beginning angler mistake. Another common angler error is to allow the fish to rest. Standing there with an outstretched rod, with no drag flying off the reel, is enabling the tuna to use the current to rest as it rids its muscles of lactic acid. Unfortuantely tuna recover their strength quicker than we do, and constantly working the fish, keeping its head facing the boat, will result in a quicker landing.Tuna have a habit of running underneath an anchorred boat, requiring the angler to dip the rod tip under the water, to keep the line from hitting the hull or running gear. Also if the decision has been made not to get off the ball (stay anchorred), a rod may have to be carried up to the bow, under the anchor line, and back down the other side of the boat. Tuna should be followed from side to side in the cockpit, particularly with outboard motors, to keep the fish from running the line under the motors.

Another cause of a missed fish is poor gaffing technique. No other situation is more disappointing than losing a big tuna after a one or two hour fight. Bluefin literally fight to their death, and gaffing is a fairly easy chore. Don't rush the gaffing job, wait for their slow circles to bring them close to the surface, then make a clean shot, trying to gaff in the head, to avoid damaging the meat. Yellowfin are a little harder to gaff at the boat, but again patience till a good shot is allowed is the way to go. Keep in mind the refractive index of the water which makes the fish appear in different spot than it actually is. My technique is to let the pole of the gaff contact the fish, then quickly lift up.

Failure Analysis

Improving your catch percentage requires analyzing the possible failure components. An empty hook coming back means the hook never set in the fishes mouth and hook type, hook sharpness, hook placement in the bait, and hook size needs to be examined. A line coming in with a broken leader requires examination of the leader. If it has a small curly end, the knot broke. If the leader broke in the middle somewhere, either the leader was knicked or the drag setting was too high. If the line comes in with no leader, obviously your main line broke. Again if the line is curled, it broke at the knot, if the line has no obvious curls it broke due to a shaffed line or improper drag setting.

Better angling technique comes with spending hours on the rod. Better gaffing work requires patience and self confidence to land the fish. Tying knots that won't fail, comes with sitting on the dock and tying them repeatedly, and testing their holding power at the dock. Checking the condition of your lines and leaders on a daily basis also reduces failure.

Keeping all these factors in mind may make you the next captain to shout on the radio, " we went five for five!"