Tags Fish Guide

Black Marlin

Tags Fish Guide
ANY angler who has witnessed a big black marlin strike a bait or lure for the first time generally remembers it well, for it is a truly awesome sight. It is a display of effortless speed and agility that belies the size of this magnificent fish.

That experience should hopefully be followed by the sound of the consistent scream of the reel as the fish peels off line as if there was no drag on it at all – and you instantly become aware that you are going to have to get all that line back on the reel. How much line can a black marlin take on its first run? The answer of course is all of it, if you’re not careful.

Big black marlin have a place in fishing folklore all of their own, as do blue marlin, and they have both been immortalised by writers like Hemmingway and Zane Grey.

Unfortunately West Australian waters are not blessed with large numbers of black marlin, and neither are they generally of the size encountered off the Great Barrier Reef. Most blacks encountered in Western Australia will not be large by world standards, but even so they are still capable of giving a good account of themselves.

Black marlin are mostly tagged and released these days, as part of an international tagging program co-ordinated by the New South Wales Fisheries Department, in conjunction with the Australian Game Fishing Association. Other global tagging programs, such as the one run by The Billfish Foundation, also collect essential information about the movements of back marlin.


Black marlin are frequently confused with blue marlin, especially when the fish are under 100 kilos in weight. However the pectoral fin on a black marlin does not fold back when pushed by hand whereas the blue’s does. The bill on a large black also tends to be shorter and heavier than that of a blue marlin.

SizeThe world record black marlin stands at a massive 707.60 kilos taken off Peru in 1953, with the Australian record standing at 654.08 kilos caught off the Great Barrier Reef in 1973. In WA the biggest black recorded weighed a mere 286.5 kilos and was caught at Exmouth in 1986. It can be seen by the dates of capture that, despite great advances in tackle design, big black marlin are not as common these days, for a multitude of reasons (see Threats).
As with blue marlin, male blacks only grow to around 180 kilos and this means that fish over this size are female, although both sexes enjoy the same lifespan.


Black marlin can be found in tropical and sub-tropical waters of the Indian and Pacific oceans, generally ranging northwards from 36 degrees south off WA. They are mostly found in the surface layer of the ocean, above the thermocline, in water deeper than 100 metres in water temperatures ranging from a chilly 15 degrees Celcius right up to 30 degrees. Generally black marlin are found not too far from land masses or coral atolls.
Breeding and migration
As is the case with highly valued marlin species, we know very little about the breeding habits of black marlin although their larvae have been found off north-western Australia between October and March. Although it is thought that black marlin spawn in waters off WA’s North-West, it is still not known for sure.
Breeding is thought to occur at water temperatures of 27-28 degrees Celcius.
Black marlin can be found moving along the west coast, close to the 200-metre isobath of the Continental Shelf as this area frequently holds quantities of small tuna and mackerel.
They can travel huge distances and one black tagged in 2007 off New South Wales was recaptured in Papua New Guinea only 59 days later. The total distance between tag and recapture point was 1474 nautical miles, which is an average of 30 nautical miles per day. Black marlin are true oceanic travellers.


It has been estimated that WA recreational anglers retain less than a handful of black marlin each year.
The largest threat posed to black marlin stocks right around the Indian Ocean is from the large foreign longline fleets, some of which operate just outside Australia’s 200-nautical mile limit. For some longliners on the high seas black marlin are one of their target species. As yet the Indian Ocean Tuna Commission has proved ineffective in reducing any fishing effort and black marlin are already recognised by Australian researchers as having stock levels well below what is desirable. Indeed some hold the view that black marlin stock may be down to as little as 10 per cent of what they were before they were fished.
The long term future for black marlin in the Indian Ocean does not look good, and sadly little or nothing is being done to redress the situation. On the other hand black marlin stocks on the east coast of Australia seem to be holding up well.

Tackle and bait

The main methods used for catching black marlin are trolling baits and lures. But these days many anglers choose to use skirted surface trolling lures, even in places like Cairns where big baits have ruled in the past. Perhaps the reason is that fishing lures is easier and can be carried out successfully even by relatively inexperienced crews. Fewer anglers these days are acquiring the skills required to successfully rig a bait that will not only swim enticingly, but will keep doing that for several hours, hence the increasing use of lures.
The best baits for marlin are probably the ones you find out on the fishing grounds, because that is what black marlin are most likely to already be looking for. Head rigging a skipping tuna to run high off outriggers is not too hard, but tuna don’t lend themselves to being rigged as swimming baits, and this is where baits like mullet come into their own. Live baits can be deadly for black marlin and these days circle hooks are becoming more popular as they minimise the deep hookups previously associated with this method of fishing.
Marlin lures come in a range of size and colours and increasingly are being fished with a single hook pinned upright, which is giving some good hookup rates with easier and safer releases. There are some great lures available these days, both from Australian manufacturers and from Hawaiian craftsmen. Because the range of lures is so large it is best to find out what works well in a specific location and go and buy those lures.
Fishing for black marlin, even in WA, is best done using 37kg and 60kg chair or stand-up outfits.

Fishing methods

When fishing baits for blacks two rods are more than adequate. Fishing baits does require the use of a set of good outrigger poles so that a drop-back can be used and the head of skipping dead baits can be held clear of the water, causing them to skip enticingly. Similarly, swimming baits should also ideally be run from outriggers.
Live baits should be carefully bridle rigged and fed back into the water while the boat is just in gear. Drop about 25 metres of line in the water between the crew member holding the line and the rod tip – this provides the drop-back required. When the bait is far enough out simply sit and hold the line (carefully). When trolling live baits it must be done very slowly, with the boat moving ahead at only a couple of knots.
When lure fishing I like to run a pattern of at least four, sometimes five, lures staggered in the wake of the boat to avoid tangles. How and where to successfully position lures is an art form that must be learned.
The common adage for marlin is if you find bait you’ll find marlin. They love tuna and slimey mackerel and are often found not too far away from them. When you find bait don’t troll your lures through it, just set up a trolling pattern around the edge of it so that you don’t put the bait down and also so the blacks can see your lures in clear water rather than being obscured by the bait.
Trolling along current temperature lines can turn up some fish too, as can FADs and other floating objects. Look for birds as a sign of where the bait is and if all else fails troll the dropoffs.
I fish a strike drag of one-third of the line class I’m using and this often results in the black marlin hooking itself. However, the increasing use of single hook rigs has resulted in anglers moving towards light drag settings that only just stop line coming off the reel at trolling speed. The drag is then eased up to strike drag when the fish is running away from the boat – not unlike fishing circle hooks.
Handling any marlin alongside the boat is potentially a dangerous business and all care should be taken to protect the crew, and of course the fish. Swim tired fish by holding their bill just below the surface of the water and moving slowly forward, with the boat just in gear, to flush water over their gills. Even very tired fish can recover.

Sea Fishes of Southern Australia by Barry Hutchins and Roger Swainston.
Stud South Coast Silvers by Tim Gray (Western Angler Feb/Mar 2006)
Compiled with the assistance of Dr. S Alex Hesp, Murdoch University.

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