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We are lucky enough to have two of the Lutjanus family of fish endemic to Central Queensland, Fingermark (L.johnii) and Mangrove Jack (L.argentimaculatus).

They are both very solid fish that have powerful teeth (hence the Jack is often referred to as 'dog' or 'dog fish') and both have big powerful tails and are very much the close combat specialists. The colour of Mangrove Jack varies according to their habitat so they present in a range of colours from silvery red to sold red and dark olive brown tones. Fingermark are generally golden bronze to silver with a grey spot on each side of the flank which looks like a finger mark (hence their name).

From a fly-fishing point of view both these species are very sort after sport fish. They turn up or start feeding as the water starts to warm as winter fades and are great targets right through till the heights of summer has passed and then gradually they move off into deeper water reducing their food intake considerably. As both jacks and fingermark mature they move out to deeper structure around rocky and coral reefs.

They chase the same sort of food items as bream, grunter and flathead including prawns and shrimp, small fish, crabs, molluscs such as rock oysters and worms so it’s not surprising that representations of prawns and small bait fish preferably tied on solid #2/0 or #3/0 hooks are great flies for mangrove jack and fingermark. That is not the end of the story for mangrove jack and fingermark as both are very territorial and will willingly take other non natural looking flies that 'inadvertently' draw their attention.

Excluding the deeper water areas mangrove jacks and fingermark are found generally in the same haunts as grunter, and each other, but for jacks and fingermark you need to work at getting your flies as deep into structure as you can . . . always remember neither will travel far for a feed.

The sort of structure they haunt when feeding is very diverse and includes natural structure such as mangrove roots, rock bar, reefs, walls, drop off's and drowned timber as well as man made structure such as bridge pylons and jetties and boat moorings. Jacks and fingermark don't more far to take a bait but once committed are very quick in the execution of their strike and are generally heading back to cover by the time they have snatched their target.

The general areas to target jacks and fingermark around Gladstone are the gutters and structure of our coastal rivers including the Calliope River, South Trees Inlet and the Boyne River, the mangrove lined back waters of the harbour and structure in local estuary bays like Colosseum and 7 mile and moving a little further away the Narrows and Turkey Beach.

BEST TIMES

The effects of the moon is a key elements in relation to bite windows

 
As a rule of thumb with other conditions remaining the same:

• The best time to fish for mangrove jack and fingermark, and most fish, is the first 7 days after the new moon.
• As for all fishing the time just before and after sunset and dawn can be a significant time for a bite window.
• In those periods of above average summer temperatures many species of fish including jacks and fingermark can sense that the barometric pressure is about to drop as an afternoon storm forms. That triggers a dramatic bite window for mangrove jack and fingermark as they feed up pre storm. Once the anticipated barometric pressure does drop and storm becomes active they turn off just as quickly as they started feeding.
• It's interesting to note that mangrove jack and fingermark have eyes that have evolved to allow them to hunt at night.

The following 3 rules of thumb apply to barramundi and there is anecdotal evidence they may also apply to mangrove jack and fingermark ... I am still seeking fact based evidence to confirm that.

1. With other conditions remaining the same is that there seems to be significant bite windows as the moon either comes up during the night or becomes visible after sunset.
2. Once it’s dark if the moon is not up it’s not worth fishing.
3. Alternatively, if the moon is up throughout the dark with other conditions remaining the same there is generally a fairly big bite window a few hours after the sun sets.

BEST TIDE

Generally mangrove jack and fingermark are most active on the last of the rising tide and the first of the falling tide. As you work through this post you will realise that a good strategy, particularly if you have a low tide around dawn or dusk, is to fish the last two hours of the falling tide and the first two hours of the rising tide.

• The rising tide gives, from a jack and fingermark perspective, small fish, shrimp and prawns are vulnerable as they move into the mangroves and other structure where they can feed and feel relatively safe.
• Once the tide inundates mangroves grunter have a tendency of moving too deep into the root systems to be able to be targeted on fly.
• As the tide changes jacks and fingermark and for the early part of the falling tide become good targets on fly.
• As the falling tide progresses and it starts to get too shallow for the jacks and fingermark they retreat from the mangroves and target and forage for the small fish, shrimp and prawns as they are flushed out of mangroves and other structure.
• Once the flush declines the jacks and fingermark retreat to holes and other deeper structure close to where they were feeding as often not accessible because of depth of the holes and the increasing run off the tide.
• On the tidal ebbs jacks and fingermark tend to school up in deeper pockets in rivers particularly during rising tides.
• Whilst active during the day the best fishing for grunter can be in the dark.
• I tend to favour neap tides when when water movement is much slower.

STEALTH

Keep in mind that mangrove jack and fingermark are easily spooked so you have to be stealthy in your movements and casts.

• So when you approach an area you going to fish do it slowly and if available quietly under the power of your electric motor and take advantage of any cover that's available. Don't cast a long shadow over or motor over over the water your going to fish. Longer casts are important and cast to the side of any fish your targeting.
• If your using an anchor deploy and retrieve slowly so that there is no bumps or chain noises that will spoke fish.

TECHNIQUES

When they are feeding mangrove jack and fingermark are generally deep in structure feeding on prawns, shrimp and small fish and if you want to consistently catch jacks and fingermark you will need to set you gear up in a way that helps you achieve accurate casts deep into and behind structure.

Another thing I know for sure is that an average size 40 cm jack or fingermark is a powerhouse and once hooked it's first intention will be to get deeper into or under cover ... they fight well above their size.

Mangrove jack and fingermark are both scroungers and predators in that on the one hand they will foraging around the bottom and in and around structure for tucker yet on the other hand they will will take advantage of structure and wait for food to come to them. They eat a wide range of tucker including prawns, shrimp and other crustaceans, crabs,worms and molluscs such as oysters. They generally feed alone or with a couple or few other fish in the same area.

My preferred gear is a #10 weight fly outfit with a straight rod length leader of 30lb Maxima Ultragreen. Depending on water depth I generally work between a floating line at the shallow end/s of the tide and and an intermediate line at the deeper end/s of the tide.

WET FLY SELECTION

When fishing wet flies for mangrove jack and fingermark, because of the need to fish deep into structure I favour flies that have some sort of structure guard or flies that swim hook point up. Having said that if your not getting snagged occasionally your not casting deep enough into structure.

Focus on repeatability twitching the fly and then letting it sit so you in the zone as long as possible. A lot of takes come as the fly settles on the pause and then the only problem you have is to get the fish out to clear water and into the net ... often easier said than done.

In terms of sub surface flies given that both mangrove jack and fingermark typically feed as deep as they can in structure you may want to consider including structure guards on those flies.

Given their diet, imitations of prawns and shrimp and small fish imitations in natural colours are a good option.

Pregnant prawn

Mud prawn

Articulated flashy swimmer

Clousers in natural colours eg. Olive or grey over shrimp

Articulated swimmer in Qantas colours

Surface and top water fly selection

The best time to use surface and top water flies for mangrove jacks and fingermark is as the tide is falling and fish are focused on bait being flushed out of mangroves. In these conditions it's worth giving your floating and top water flies a swim because the surface action can be exhilarating.

Articulated booby

Popper

Wiggle minnow

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