Hard Body Jack Tactics
  |  First Published: February 2007

Mangrove jack are the rascals of north Australian estuaries and often beat anglers at their own game. Hard, fast and powerful short runs often give the fish an advantage when the fight is near structure. When casting at snags you have to be ready to give the fish a bit of curry in a hurry. That first burst of adrenalin from the fish usually determines who wins the battle.

Mangrove jack have always been my saviour when chartering in Cairns. I don’t think I ever had a disappointed customer when jacks were out on the chew. They were my second most requested target estuary species after barra. Fish between 1-2kg are prolific around the tidal reaches of our northern rivers and estuaries and are frequently caught right up into the far fresh water reaches whilst targeting other sport species.

Jacks are caught in northern NSW in small numbers but as you travel north along Queensland’s east coast their numbers increase and they extend all the way around to the north west of WA. Any 50cm jack is an exceptional estuary specimen even though they do grow to 15kg. The larger fish usually migrate out of the estuaries when they reach 45-50cm and school up in deeper water around structure. However, trying to tackle them out of the estuary environment is a totally different story.

Trolling the Creeks

Trolling is scorned by some but worshipped by others. I’ve found that trolling for mangrove jack can be deadly. It’s an effective way to introduce inexperienced anglers to lurefishing and a great way to explore a new area. I’ve spent many relaxing afternoons sipping on a beverage, trolling up jacks and just enjoying life.

In my early 20s, when I first started experimenting with lures, I occasionally trolled up the odd jack and a few other species in the Gold Coast canals and the Fisherman Island rock walls in the Brisbane river. When I moved to Cairns where the jack population is considerably thicker I adopted the same tactics with instant success.

The most important factor when trolling for jacks is to be ‘in the zone’. I think the ideal zone is around 30cm off the bottom. The occasional puff of sand or bump over a log doesn’t hurt – it can even be a turn on. You don’t want to be on the bottom all the time or you’ll end up retrieving a lot of lures with a tackle back. Lifting and lowering your rod as you watch the sounder will raise and lower the lure in the water column. Letting out or retrieving line will do the same thing.

Stagger your lures to try and cover as much area as possible and to avoid fouling on bends. If you’re spreading different depth lures, place the deeper divers in close and the shallower lures further back. When working a new creek take the time to map out your troll path concentrating on the channels, structure and mangrove undercuts. It’s possible to troll more than three lines a side when targeting deep mangrove undercuts or steep snaggy banks if you stagger them correctly. However, it’s tough to land fish if there are only two of you.

I’ve found that the best creeks and canals have an average low tide depth of 2m. I have used downriggers to troll for jacks in depths to 15m, but the deeper you get, the thinner the numbers although there is a distinct increase in quality. Once you start targeting deep structure fingermark, trevally and pesky cuda become a more frequent catch. You will get onto the odd patch in deeper water and on rock bars but the shallower creeks are much more predictable, reliable and thicker in numbers. Once you catch a jack, work over the same area a few times as there are usually a few hanging out together. They are probably there in the same area for a good reason – food availability!

90% of my trolling in the estuaries was done with the big 4 banger at idle speed. The noise of the engine doesn’t seem to deter jacks except in the smaller constricted creeks.

Twitching a slowly trolled Jack Snack or Barra Pro Mini behind an electric motor in these small tropical creeks on hot summer afternoon low tides can be deadly but the average size lacks a little.

Get to know your local creek because the more you troll it, the more better you will become.

Casting the Snags

This can be brutal! Once you’ve been bricked by a jack back into the snags you realise how important it is to get the upper hand straight away. I’ve seen balls of fish fighting for a lure as it’s retrieved from the snaggy haunts they reside in.

When choosing a bank I always look for deep snags, shady mangrove undercuts and mangrove root lines that are still submersed at low tide. Run-off gutters and creeks with snags at their intersection are usually a sure thing.

Once you’ve picked a likely looking area, drift past or anchor up at a comfortable casting distance and cast at the structure as closely as possible. Don’t sit on a snag and flog it to death, if you don’t get a hit within six casts move on. Casting accuracy determines the success of a trip especially when the fishing is a bit tough. If you’re not getting your lure into the thick of it – you’re not in far enough.

An electric motor is a must for anyone serious about targeting jacks but a mental calculation of the tide, current and wind can also work depending on the severity and circumstances of conditions. If you don’t have an electric and drifting just isn’t working, anchor back off the snags and work them over. This is more time consuming but usually results in more fish being hooked.

Take the time to work out a game plan. I usually head upstream and pick the prime looking banks, work my way back down the chosen sections with the outgoing tide and then back up with the incoming tide. This helps save the battery power for the electric motor especially on extended trips.

Jacks are usually responsive to medium/slow erratic deep retrievals, but experimentation always is the key. A good place to start is with a buoyant lure that will dive down the snag face a little. If you hit the snag just let your lure float up a little and continue retrieving.

Poppers also take their toll in the snags particularly in the upper freshwater reaches or on the mangrove fringes around the neap tides. This is a much more visually rewarding style of approach suited for low light situations (first light, last light and shaded areas).


As with most species, tide and moon phases influence the feeding patterns of mangrove jack. They can be caught at day or night, on low or high tides but attention to tides and applying the right techniques for those tides can make all the difference. The best luring time, for casting and trolling, is the two hours either side of the low tide change. At high tide, anglers should target them on the flats areas around mangrove fringes and rock out crops. No run – no fun! I have found the most consistent results come from 1-2m of run-in tide. The five days leading up to the new moon are a good time to target them and the lead up to the full moon also produces good numbers.

Jacks tend to go off the bite in the cooler months when the water temperature (12-20) drops suddenly. You can still catch them in winter if you float live baits into the snags or target them at night on the mangrove flats. I imagine that further south you would get a slightly shorter bite period over a year. Jacks, like barra, respond well to sudden rises in the water temp and react badly to sudden drops.

In Cairns, jacks are not considered a viable target species for charter operators from May to August. In my home waters when the water temperature rises back up to 22-24 jacks go in search of food just like a bear coming out of hibernation. The warmer the water, the more energetic, curious and troublesome the fish become.


A 3-5kg spin or bait caster combo will do the job fine depending on your preference. Use the best gear you can afford and look after it.

I use a Daiwa Sol baitcaster and a Loomis 662 but an Abu full of 20lb braid and an Ugly Stick would knock over the average fish you’re likely to encounter. They won’t be taking long blistering runs but you will need to lock the thumbs down and pull the bigger fish up short if they head home in a hurry. You might pull a few hooks but it’s better than loosing a few lures.

When trolling back the drag off a little especially if the rod is in the holder because they hit very hard. There’s a lot of inertia behind the boat, when the fish hits a trolled lure the boat keeps going, the rod bends a little and something has to give. Don’t be lazy, hold your rod and use your arm as a shock absorber.

For leader I recommend about 1m of 40lb mono or fluorocarbon attached via a double to the main line. No swivel! I prefer to use a perfection loop but a snap clip can be used for ease of changing lures.


Match the hatch in size more so than colour and match your lure to the depth in which you’re fishing.

Most of the lures I use for jacks are between 5-10cm. Mann’s 10+, C-Lure Jack Snacks and Barra Pro Minis are my all time favourites. Use sharp hooks; this is very important for your hook up rate.

I’ve seen jacks caught on every colour of the rainbow but I usually start off with a natural colour. On some days one particular colour will catch every fish and on others they’ll hit everything you throw at them. Remember tomorrow might be a totally different story. What works today might not be in season tomorrow however it’s still a good place to start.

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