Dogtooth Tuna (Gymnosarda unicolor)

By Fred Steynberg

This must be one of the fish species that the bulk of the salt water fly fishing fraternity would want to release after a couple of ‘trophy’ pics for the study wall. It is one of those fish that requires fly fishermen to travel to far away destinations and work hard for. Over the years anglers have become fascinated with these beauties because of their rarity, sheer size, aggressive and unexpected takes and hard fights.

Fred with a Dogtooth Tuna

The odd fish hooked and landed on fly gear was and still is considered a fluke. ‘Under-gunned’ is a  phrase I have often heard from ‘hard core’ conventional anglers referring to fly fishing tackle, when discussing Dogtooth Tuna, and here are a couple of reasons why. ! 

The Dogtooth Tuna is a large fast swimming fish in the family Scombridae (same family as our common King and Queen Mackerel, Bonito, Blue fin and Yellow fin Tuna).  It has large teeth and a straight edged first dorsal fin that is able, like that of the Yellow fin Tuna, to retreat into a well designed slot when the fish is in turbo mode.  This streamlines the body when it attacks or speeds away. They can grow to weights exceeding 150kg (330lbs) and at a weight anywhere near this mark will be a great contender on almost any fishing tackle.  The astonishing average weight caught on fly on all the excursions that I have done in the Indian Ocean during the past 15 years is around 20-30kg, already a large fish in anyone’s book.

Dogtooth on fly

Dogtooth Tuna are one of the apex predators in its environment and are non-pelagic, unlike the other family members. This means that they can be considered territorial, much like the Giant Trevally (GT) or large Groupers that select a specific area that have all the necessary attributes for such monsters to survive in.

Attacking their prey without hesitation and if not crunched and consumed whole then their large, sharp teeth can easily cut through fish flesh if smaller pieces are necessary. I have often seen smaller doggies come in on the hook with bite marks around the lower body and tail area and suspect that this comes from other doggies in the pack that will bite the hooked fish once they have resumed a feeding frenzy.  Doggies can be solitary hunters but are often seen by spear fishermen and scuba divers patrolling the drop-offs in pairs or small hunting packs.  They thus do not shoal in large numbers as with their other family members and are hardly ever found feeding on bait fish that have been trapped in shoals within the surface column of the water.  Once hooked they often use strong, speedy, deep, downward runs as a tactic to free themselves from the straining force. These tactics often cause the anglers’ line to cut on deep structures, especially when fishing close to sheer drop-offs.  Sharks, if in the vicinity, often mutilate hooked fish, especially if the duration of the fight is prolonged by lighter tackle, bad fighting (angler) techniques or the size of some of the monsters.

Being opportunistic feeders they predate on a wide variety of fish species such as Rainbow runners, Scads, Fusiliers, Half beaks, Flying fish, and other reef species. This poses a big problem for the fly fisherman because this means imitating a rather large prey and there is a limit to the size of the fly that can effectively be presented. This is one of the reasons why fly fishermen often hook the smaller 10 – 40kg fish; these fish can replace their energy chasing after smaller prey whilst larger fish need a larger food source.

Dogtooth Tuna on fly

Smaller specimens can often be found in shallower waters close to drop-offs (often referred to as walls) during fading light conditions (early morning and later in the evening) or darkness. They seem a lot more at ease venturing into the shallows in low light conditions and are then less selective.  Dark profile flies seem to work well under these conditions, especially large Black Whistlers and Zonker style flies that create movement and have added weight.  Large deceivers and deep water clousers are also an option but make sure that the hook is a strong, wide gape # 6/0 or 8/0.

Larger fish prefer the deeper water and patrol around the walls of drop-offs, much like giant Grouper and GT’s.  Unfortunately for them they are inquisitive and often would not shy away from divers.  The fact that they usually swim at depths beyond 50m makes them a difficult fly fishing quarry.  Fly anglers can really only effectively reach depths of 20 – 35m with weighted fly-lines and flies, considering current strength and the speed of the drift.  It is possible to use heavier fly lines and to add more weight in the fly to achieve greater depth, but the more weight; the less the entire process can be called fly fishing. (This is when a fly fisherman ventures too far from the true fundamentals of the sport).

We always suggest that our clients use 12 – 14 weight rods with good quality reels that have excellent drag systems. The rod should be shorter than the average 9’ + casting tool, 8’ – 8’.5’’would be the preferred length.  Distance casting when targeting doggies is not important, of more importance is the strength and lifting power of the rod and this is achieved with a shorter rod.  A shorter 12 – 14 weight rod can be used for all-round deep,   offshore fly fishing.  It is of primary importance to land/release the fish as soon as possible for reasons already mentioned.

Linecatsers Black whistler

Doggies look as if they can run a mile when hooked, especially on fly tackle. Under the correct amount of strain, however, and with the correct tackle they should not run more than 50 – 100m at a time. I have witnessed large doggies run further but the large specimens are rare.  No less than 300m, 50lb backing of good abrasive ability, such as Spectra Tuff or Tuff line will suffice.

We use 500 – 700 grain depth finders and find that with the correct fishing technique the line should reach depths of 20 – 30 meters.  A fly at this depth might even attract a Dog tooth that is patrolling further down.  An 800 grain (lead core) fly line can be used but they are extremely heavy and uncomfortable to use and in my opinion not a fly fishing tool. Many fish species often feed on the outgoing and incoming tides, so the peak offshore fly fishing time will almost always coincide with stronger water movements.  Often when fly fishing a drop-off with currents in a lull the fly and fly line could sinks straight to the bottom.  This is normally when the action stops or slows down until the tide turns again.

Doggies are found in crystal clear, warm, tropical water and they depend heavily on their  eyesight, among other senses, to locate their food.  When fishing with trawling, spinning or live bait tackle (conventional), doggies often excuse heavy wire traces and accept the offering. When fly fishing, however, fish will often not eat the fly if a steal trace (shock tippet) is used, nylon coated or not.  It could be that the action of the fly is impaired by the stiffness of the material or it could be the fact that it is more visible than the nylon shock tippets.  

When one looks into the doggies mouth it appears as though it would be able to bite through the thickest nylon on the market but unlike the teeth of for example Tiger fish, Wahoo or Shad; Dogtooth Tunas’ teeth are sharp but not serrated and do not lock together perfectly when the jaws lock.  A 60 – 80 lb mono or fluoro carbon shock tippet works for us.  This does not imply that every doggie hooked on monofilament or fluoro carbon will be landed, some will be lost, but the hook-up rate is greater. If you feel uncertain about using nylon then a shorter piece of steel will have less of a negative affect on fish and can be used.  The problem with this is that doggies often swallow the fly deep and a short steel trace will then render itself useless.  I have often witnessed anglers using a foot or two length of nylon coated wire or piano wire as a shock leader and they have very little success.

Small reef fish often grab the large flies when we drift from the shallow banks, 12 – 20 meters deep, towards the drop-offs, in search of doggies.  Amazingly these fish that weigh no more than a pound or two accept large flies.  Once hooked they add very little resistance on a 12 – 14 weight fly rod and are often stripped back with the hand that manages the fly line, without using the reel.  The struggling little fish can attract the attention of a Dogtooth swimming in the vicinity.  They often pounce on the little fish as it lifts off the bottom on the way to the surface.  This astounds the angler who thinks that their little hooked fish has suddenly come to life and turned monstrous.  The ‘live bait’ is taken with such vigor that it may at times be swallowed right down into the Dogtooth’s stomach.

It must be said that different chumming methods can be used to attract Dogtooth Tuna to the boat and can be extremely effective in low light.  Fly fishermen, because they drift freely, need to constantly move position to stay within the target zone and the effectiveness of the chum-line is then lost.

Dogtooth Tuna are by any means one of the most ferocious hunters in the tropical waters, and give a good account of themselves when hooked on any tackle, but there is a down side to hooking and landing these beauties.  They do not revive well, in fact half the fish that we have seen landed did not survive and this can be a huge waste especially on a trip where freezing space is minimal.  Some say that it’s the expanding air bladder of the fish that keeps it buoyant but this can surely not always be the case as fish often only intercept the fly a couple of meters below the surface.

Doggies in my opinion fight their ‘hearts out’ and are often completely exhausted by the time they are landed, especially when using lighter tackle, complicating reviving the fish.  It might be a good idea to release them while in the water and not to pull them onto the deck.  Problem is that we all would like a photo for some ‘bragging’ rights later.  A hose that pumps salt water through the fish’s gills could be used to oxygenate the fish but even then the fish should not be out the water for longer that a few seconds.

It sounds a little cliché but these fish are not as plentiful as we would like to believe, making catch and release necessary. Their habitat is in some parts of the world under serious pressure and large fish are rare in areas that have been over fished.  They are in a way much like (especially the big guys) the old Potato or Brindle Bass that have for many years lived in their territory and have become such an intricate part of the system.  Indiscriminate harvesting of these fish by spear fishermen and fishermen alike can place this fish out of reach for many sportsmen.