Light Tackle Billfish Part 4 – Finding Fish


Hello and welcome to the fourth instalment of Light Tackle Billfish Part 4 – Finding Fish.  To anyone who is visiting for the first time I suggest you start with Part 1 of the series “Gearing Up”.

   Well, to all those who have read the previous parts of the series you will have to bear with me on this one as it wasn’t easy to do and may not be so easy to read but I can guarantee that there will be some good information here anyway!


   This topic really should have been brought up earlier in “Part 1 – Gearing Up” but better late than never.  Get the best set of polarised sunnies in a saltwater tint you can possibly afford and don’t use them for anything but fishing. (I need to heed my own advice on that last bit)  They are by far your best tool for finding fish.  If you don’t have a good set of polarised lenses you might as well forget going Billfishing until you get a pair THEY ARE THAT IMPORTANT.  You are just going to have to take my word on this until you see a couple of fish in the water and then you will understand exactly what I am talking about.

Where To Start?

   Ok, so you have spent all week prepping your boat and gear to go chase some stick fish and you just can’t decide where to go… How do you figure it out?  Well the easiest way to do this when you are starting out is to research your area and target specific areas that are known to produce Billfish either historically or currently.  The reason I make this distinction is that many people hold off going fishing for other species if they don’t hear reports.  Well I’m here to tell you if you are chasing Billfish in the Territory and also in other locales then you may just have to bite the bullet and go because if you wait for a decent report you may never go!  On the other hand if you get a report that a certain area is firing get there pronto!  If you are relying on historical catch data to target an area just be sure that you are giving yourself the best chance possible by making sure you are there at the right time.  For example, from my observations there are two runs of fish in the Territory one from Febuary to June and another during the build up from September to November although I suspect there are fish in the Territory year round.  In my opinion the grounds wide of Dundee fish better in the earlier part of the year with the deeper water of the gutters fishing better later in the year.  All this brings me to an important point, to catch Billfish you really need to fish where they are likely to be so going to places they have been caught before is a great way to start.  Below is a rough map indicating the areas that have produced fish around Darwin.

Darwin Billfish Map

On The Water

Have a Game Plan

  Ok, so you have finally made it out to the grounds, deployed your trolling spread and settled in to try and catch some fish the question is what do you do now?  Well the first thing you need to do is have a game plan for the day.  This plan can change rapidly as the day progresses but it always pays to have one.  A good example of this is when I fish North Gutter I will start my day at the top of the Fenton Patches and head for the eastern end of North Gutter.  When I reach the gutter I will then run along either of the drop offs switching sides when I come to a choke point in the depth contours.  I will generally plan to be at the western end of the gutter during the change of the tide for the optimum bite time.  However, if at any time I find bait or sight/raise/hook a fish I will give the immediate area a good going over and may not move far from that point for the rest of the day.


   The first thing to look for when trolling for Billfish is structure.  This holds true for all types of fishing and billfishing is no different but the structure itself may be not as readily visible nor be what would traditionally be described as structure in an estaurine situation.  Even if there is no discernable predator or prey movement in association with structure it is still helpful to the fisherman as a point of reference whilst trolling. When trolling for billfish anything that deviates from a flat bottom and bare water column can be considered structure.  To make it easier to get a handle on I will seperate open water structure into two parts, surface and subsurface structure.  Lets start with subsurface structure, we will classify subsurface structure as anything that cannot be seen by the naked eye.

Bottom Contours

If you look on a GPS Map you will see countour lines which indicate points of the same depth on the seabed as different contours show different depths this then makes it easy to pinpoint peaks, shoals, gutters and holes in the sea floor all of which either provide structure to hold bait or influence the current to varying degrees or both.  A prime example of using the contour lines on your GPS maps to find fish is targeting Cul-de-sacs formed by the contour lines along a gutter.  These cul-de-sacs act to funnel the prevailing current to the surface in the form of nutrient rich upwellings which in turn attracts the bait and predators.  North Gutter is a prime example of this phenomenon, in fact, at certain times of the year it is that reliable that every large cul-de-sac in the gutter holds a school of tuna or Mackerel and of course the billfish will be lurking somewhere nearby.

Bottom Strata 

   Some types of bottom strata seem to hold bait better than others.  Mud or sand doesn’t appear to hold much in the way of bait unless it is packed into tight travelling schools whereas a firm mixed rubble bottom seems to hold looser schools of scattered bait more consistently.  Areas like this are excellent to target if the Billfish are scattered and not really herding bait as they tend to produce consistent singles and pairs of fish.  The long Lost grounds wide of Dundee are a perfect example of this type of ground.

Wrecks, Shoals and Pinnacles

   Wrecks, shoals and pinnacles are fairly obvious forms of subsurface structure and all are prime bait holding locations found by using your GPS maps and a quality sounder.  Even a small lump has the ability to attract bait and influence a wide area so anything holding bait is worth a closer look.  Here is a screen shot of some hard structure holding bait.  Whilst bait is holding hard against the structure we also can clearly see that it influences the bait density across the entire water column and this is what we are interested in.

Lowrance HDS screenshot.

Current Lines And Upwellings

   Current lines can be regarded as both surface and sub surface structure.  There are a huge variety of current lines, some with debris such as weed or foam caused by wind and friction between the bodies of water moving at different speeds and often in different directions.  Distinctly seperate bodies of water form due to differences in both salinity and temperature which both affect the water density.  Different densities of water resist mixing and therefore have the ability to form these separate currents. Current Eddies are caused by the friction of the water currents both on and below the surface. And it is in these areas, especially on the edges that we find the greatest mix of nutrients, oxygen levels and temperature variances.  This in turn attracts the greatest concentrations of bait and predators.  In addition, from a predator/prey perspective small bait fishes are unable to travel through temperature changes and associated salinity and oxygen levels easily. Larger predators take advantage of this “wall” to herd bait fish more easily than in the open ocean.  Here is an example of some current lines with both rough and calm water corridors evident and a distinct colour change in the fore ground.

Current lines with colour change


   Weed is considered to be a nuisance by many fishermen but it is an excellent form of structure to look for when  searching for billfish.  By far the best is Sargassum weed as one of the billfishes’ favourite prey food the Flying Fish uses the weed to spawn on in addition to using it as cover.  If you see any commotion in or around floating weed get up there fast as it is quite likely there will be a lit up fish waiting for you.  A particularly memorable example of this happened at Long Lost last year.  We spotted a commotion on the surface close to some floating weed some distance ahead of us and proceeded to head in that direction.  When we got there a Sailfish of around 20kg was there.  He was that lit up and aggro from chasing flying fish around that he was batting a small piece of driftwood around with his bill!  Needless to say he didn’t turn down the bait we pitched to him….   This is an example of a Sargassum weed raft if you look closely you can see it has formed on a current line. 

Sargassum Weed Raft

 Assorted Floating Rubbish and FADS

   Any floating rubbish at all no matter how small has the ability to hold baitfish and is always worth a look.  As example me and a mate were fishing Darwin harbour recently and came across a couple of empty chip packets floating in the water.  When we went over to pick them up we discovered there were 5 or 6 small baitfish sheltering underneath each of them.  If nothing else floating debris may be holding Dolphin fish, Tripletail or Cobia. The shipping pallet in the photo below is a prime suspect.

Pallet FAD

Other Predators

   Other predators in the area are always a good indication of bait in the area and are invariably worth taking note of.

Turtles And Sea Snakes

   Both Turtles and Sea Snakes are excellent indicators of good bait fish concentrations in an area.  Turtles in particular seen to have a preference for the sort of water Billfish are found in and I always regard them as a good sign.

Tuna And Mackerel Schools

   Depending on the size of the individuals in a school versus the size of the Billfish in the area Tuna and Mackerel schools may or may not be prey items.  Billfish will still hang around Tuna and Mackerel  schools even if not feeding on them and they may be feeding on the same baitfish so it is always worth a troll around the vincinity of a school.  In addition Tuna schools in particular can serve as excellent points of reference when trolling in an area.  For example wide of Dundee I will regularly troll from school to school if there are tuna spread through a large area of interest, it breaks the monotony and is often a productive technique although it can be hard to resist putting a lure through sights like this…

Tuna School


   There are a vast array of seabirds that can indicate the presence of bait and predators but in the tropics there are three of particular note to the Billfisherman.  All birds exibit certain behavioural characteristics in the presence of baitfish and predators and only time on the water can really key you in to what is happening but in short any bird that is trying to hold station in a given area or is diving consistently is worth investigating.

Common Tern

   The common tern is the most prevalent bird you will encounter offshore in the tropics.  It will reliably indicate the presence of small to mid size bait and is common on both Mackerel and Tuna schools.  It will also be in attendance when Sails and small Blacks are feeding on Sardines, Anchovies and Herring.

Common Tern

 Northern Gannet

   The Nothern Gannet is an excellent indicator of both large bait and the apex predators that go along with it.  A single Northern Gannet holding station is always worth closer investigation as it is more than likely there will be a large predatory fish underneath.  Northern Gannets possess the ability to dive deep after bait and watching a flock of them do this is Awesome.

Northern Gannet

 Check out this video to see what I mean.  I watched a flock of Brown Boobies do this in Broome and it just blew me away.

Brown Booby

   A close relative of the Northern Gannet, Brown Boobies exibit the much same behavioral characteristics.  If you see a number of these birds in one place chances are the action isn’t too far away!

Brown Booby


   Needless to say baitfish are the key to success in finding Billfish and the old adage “find the bait and you will find the fish” will lead to success the vast majority of the time.  All of the above is aimed at finding both the bait and the attendant predators but sometimes bait won’t have birds on it and will be seen as a slight ripple on the surface or it may be picked up on your sounder in the middle of nowhere just to remind you that there are no hard and fast rules when it comes to fishing.  Billfish can, and will feed on just about any fish that they can swallow but there are predominant bait species in any area and they do have their favourites.

Sardines, Pilchards, Herring and Anchovies

   All these baits are much favoured by Sailfish and small Black Marlin and are assumed to comprise a large proportion of the inshore Billfish diet in the tropics.  This grouping of baitfish is sometimes hard to tell apart but will look something like the following:




 Flying Fish

   If there is one bait that screams Billfish the Flying Fish is it.  This bait is the main cause of free jumpers and they really get the Billies revved up and in the mood to feed.  As previously stated Flying Fish spawn on Sargassum Weed and the Billfish will hang around in hope of a feed if Flying Fish are in the area.

Flying Fish


   To be honest I’m not sure how prevalent Garfish are as forage species for Billfish but I do know they inhabit the surface of offshore waters.  Regardless of this one fact is undeniable, Billfish love them and in my opinion they are the Numero Uno billfish bait in Northern waters.   Garfish lend themselves well to rigging with circles.  They can be quickly and easily rigged to swim like Ian Thorpe and given their slender shape they pitch very well.


Mackerel and Tuna

   Make no mistake for any reasonable sized Billfish both Mackerel and Tuna are very much on the menu.  In the North small Spotted Mackerel in particular make excellent skip and swim baits.  A very similar species that Americans call Spanish Mackerel is used extensively in US waters.  Towing a Mackerel as a skip bait on 15 or 24kg tackle gives a two fold advantage. Firstly it puts you in the game for a serious sized Marlin and secondly the bait will work just fine as a teaser for any smaller fish that may show up.  Small Queenfish are a good substitute for this senario, in fact they are probably even better.


 Sighting Fish

   So far we have talked about observing the signs that will increase our chances to find Billfish when on the fishing grounds but by far the most exciting way of finding fish is to sight the fish themselves.  The slightest sign of movement on the surface should be investigated.  At the least it may be baitfish movement which is one of the things we are looking for anyway.  But it is surprising just how often it is a Billfish and depending on the mood of the fish these sightings can most certainly be converted into hookups.  For years the Striped Marlin fishery in Southern California has relied on this as their primary method of catching fish.  To put it into a local perspective here’s some stats from my last season, out of the 21 fish the boat released in the 2010 season 6 out of the 21 releases were from free swimmers.  Nearly a third of the total and that included the largest fish for the season a 80-100kg Black.  So as you can see keeping your eyes open is well worth the effort.  This is also the reason why I make such an issue out of having a pitch bait ready and waiting at all times.  When it comes to Black Marlin be aware that in the water they don’t often look Black.  Expect them to be any colour from pale blue to a deep purple, light moss green and even a drab brown. The fish will most likely change colour as it “lights up” to attack your bait. Sails are mostly a beatiful blue/purple with neon blue highlights when they are “lit up”.

Free Swimming Sail

    I hope this has helped someone out there in their quest for a Billie.  Stay tuned for the next installment Light Tackle Billfish Part 5 – Trolling tactics.



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4 Responses to Light Tackle Billfish Part 4 – Finding Fish

  1. deepblack says:

    Great stuff mate, great to hear you’re getting amongst them.

  2. jonr says:

    Hi john
    – I followed your tips and got my first sail this week – but dropped about 10.. I am hooked now


  3. jeffish says:

    Gday John
    Very valuable info here,can,t thank you enough for putting so much time into this.
    Hope to post up pic of my first billie soon,,so far only done about 50 hours on the hunt
    and only raised one,but no hook up,,,next time for sure.


  4. trevor schultz says:

    Hi John

    just finished reading your blog, and would like to congatulate you on a fantastic job so much valuable information. Thoroughly enjoyed reading it. Thanks for sharing.

    Cheers, Trevor

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