by Gavin Smithers
Billfish are found in all oceans in tropical waters and seasonally into latitude 40 in warm currents. They are generally oceanic but can be found in coastal waters also. Some areas of world renown include Hawaii, Baja Mexico, Florida, Great Barrier Reef, North Western Australia, The Pacific Islands, New Zealand, Mozambique, Natal in South Africa, Tropical West Africa.
I live in Coffs Harbour, on the East Coast of Australia, and this article is focussed on Marlin and Sailfish in Australian waters. However many of the observations in this article can be applied to hunting overseas.
There are three billfish in Australian waters which are a chance for divers operating offshore, these are Black Marlin, Striped Marlin, and Sailfish. Other Australian billfish include Blue Marlin, Swordfish, and Spearfish but these are less reliable.
Black and striped Marlin are chased by divers in NSW, Queensland and in smaller numbers north of Perth, Western Australia. In eastern Australia Black Marlin are found year round in the north and during summer in NSW. Striped Marlin are found in summer in the south and in cooler water months further north.
"Black Marlin have the potential to reach well over 500kg..."
Black Marlin have the potential to reach well over 500kg. The current Australian spearfishing record is 176.9kg. Striped Marlin may reach over 200 kg. The Australian record is 99.5kg.
Black Marlin are more likely to be encountered in coastal waters while Striped Marlin tend to be found well offshore. A Black Marlin is a possibility whilst chasing Mackerel in Northern NSW or Kingfish etc at southern locations such as Jervis Bay or the Banks. A number of big Black Marlin have been taken in relatively shallow water in Natal, South Africa. Striped Marlin are more likely whilst targeting Marlin, Tuna or Dolphin Fish far offshore.
Young Black Marlin are the most likely Marlin to encounter as they migrate down the East Coast during summer. Most fish are 80 kgs or less and are a possibility even for shore based divers. Darren Higgins took one at Seal Rocks from the shore. Hotspots include reefs or islands off the Sunshine Coast, Gold Coast, Byron Bay, Coffs Harbour, South West Rocks, Forster to Port Stevens , Jervis Bay, and the Banks. The run commences in January on the Sunshine Coast whilst April would be better in southern NSW. Warm, clear water with current from the north (or south if in Northern Hemisphere) are advantageous. Any reef or Island with bait on it could produce a Marlin. Dive on the up-current side near bait, as for any pelagic fish. Bigger Black Marlin could be encountered on the Barrier Reef especially on outer reefs.
Striped Marlin are often fished near the hundred fathom line. Black Marlin also are found here. They are a difficult target for a spearo as there is a lot of water out there, also good boats are needed to operate well offshore.
Striped Marlin have been taken while trolling teasers. Dead baits or game fishing lures are trolled and when a Marlin strikes, a diver can enter the water and hope for a shot at the swift moving, excited fish. Keep the teasers simple and near the boat. Marlin come up to investigate engine noise and are not shy. The late Mark Searle took a Stripie like this.
Hookless teasers are towed close behind the boat while the diver remains prepared for a quick entry should a billfish appear. Riglines are coiled to allow tangle free deployment.
Baitfish schools in deep water have a good possibility of billfish and tuna being found under them. If you are lucky enough to come across bait schools in deep water check them out but watch the bities! Ian Puckeridge and Paul Riordon recently took good marlin from a baitball off Port Stephens. Improve your chances trolling or finding bait offshore by looking for bird activity, current lines or temperature differentials, and known spots such as the edge of the continental shelf or over canyons. Speak to game fishermen, they are a wealth of knowledge.
We have raised tuna by berleying along the hundred fathom line. Marlin also respond to berley. Use small cubes of fresh fish or cubed trap pilchards. Don't use tuna oil or make surface slicks, both will bring sharks. You need light wind conditions or the boat drifts from the berley too quickly. Deploy a flasher in the berley trail. This is not the place for a screw up, make sure you have a boatie and stay close to the boat.
Sailfish are similar in habits to small Black Marlin. They can occur from Port Stephens north on the East Coast and are taken in north western Australia. Sailfish are also taken in the Coral Sea. Sailfish can reach 100kg. The Australian record is 63.2kg.
Try the hotspots listed for Black Marlin in summer-autumn. Warm water, current from the north and schools of Alligator Gars are good signs. We have had success diving in about 30m of water up current from reefs and islands.
Finding billfish is the hard part. They are self assured and inquisitive, so spearing them is not that difficult but landing them may be. Billfish respond well to flashers. I have taken one Marlin checking out a Rob Allen flasher and it presented a fairly easy shot. Marlin and Sailfish that I have taken or seen while diving without a flasher have all glided in for one look and then headed off , presenting shots from broadside or from slightly behind. None have been very shy. Aim for the shoulder or mid body above the stomach cavity. Small Black Marlin are soft and spears can work loose. Sailfish have pretty tough skin and spears hold well. Rob Allen notes that the spine is widest where it joins the head exactly where the top of the gill plate ends. He recommends this as the place to aim for if possible. Rob also recommends that big marlin need to be shot near the head or the subsequent fight to land the fish becomes extremely difficult. This is because a fish shot or hooked towards the rear is constantly able to swim away from the direction of pull rather than being lead in the direction of pull.
"be mindful of dangers..."
If you should find yourself attached to a big fish, be mindful of dangers such as coils of rigline, currents, sharks, and the billfish itself. Fight the fish patiently, conserve your energy, do not get too far down-current of the boat unless someone is keeping watch on you and don't try to subdue the fish if it is still lively.
Equipment needs to be well maintained and strong. I prefer to use an 11 litre solid float and always have some bungee in my rig. The role of the float is to prevent fish diving too deep and to retrieve fish if they do dive. Floats, therefore, must be strong enough not to implode at depth if a fish sounds. One litre of float volume provides one kg of lift minus float weight. My float of 11 litres therefore provides about 8 kg of lift - similar to the drag used on 25 kg game fishing gear. This will return most fish to the surface within a few minutes but they may have covered some distance by then! If chasing big Marlin two floats would be better. Use bungee between floats if you use two in order to provide drag incrementally.
Guns can be either European style or American. The European style guns of 1.3 m or so are light and versatile and have the advantage of being able to take smaller fish and bottom fish while diving. The American style guns are heavier, have multiple rubbers and are more specialised. Properly rigged they are very powerful.
American style guns are more suitable if diving in places where Marlin or Tuna are your only targets and where unloading and reloading are not regularly required. Unless chasing extremely big fish 8mm spears are heavy enough and 7mm spears in European style Rob Allen guns have taken the world records for Black Marlin and Sailfish.
Floats, lines, crimps, attachment points to guns and spears, shooting lines and floppers or detachable heads all need to be assessed for strength before tackling big fish.
Eating qualities of Striped Marlin are good, as are smaller Black Marlin. Black Marlin have a high mercury content and are probably not a fish that you should eat frequently. Smaller Sailfish are quite palatable but not as good as the Marlin. Happy Hunting!