Scott’s Species – mangrove jack, an aggressive inshore opponent

In this week’s edition of Scott’s Species, Western Angler editor Scott Coghlan casts his attention to WA’s north and discusses a formidable inshore opponent — the mangrove jack.

Species: Mangrove jack, Lutjanus argentimaculatus
Eating: 4 stars.
ID: Copper/crimson colouring, large teeth.

Jacks are aggressive beasts, as show by this one which hit Scott Coghlan’s stickbait intended for a GT!

One of the most fun fish to catch in our northern creek and inshore waters and superb looking with their crimson colouration and prominent teeth.

Jacks are an aggressive predatory fish that grow to more than 15kg and more than 1m in length, but are usually encountered at about 1kg to 2kg.

Big fish caught offshore are a striking sight.

The biggest jacks are found on offshore reefs, but small specimens can be prolific in estuarine and inshore waters from Kalbarri north, although they sometimes do show up farther south and have been caught around Perth marinas at times.

Exmouth Gulf has some great populations of jacks in its creeks, and they are spread through the Kimberley and Pilbara.

Some of my best jack fishing was sight casting to them in clear water at Kuri Bay.

Jacks love to gather around rockbars and snags and in tidal creeks and are renowned for their ferocious attacks on bait and lures, often diving back into cover before the startled angler realises what has happened.

Fishing structure is a sure way to encounter jacks and gear needs to be sturdy to cope with the initial strike and fight.

Jacks like to head straight for cover, as Jason Coleman found out in an Exmouth creek.

They will take just anything when they are in mood, including all the usual fish baits, lures and flies.

Soaked bait can be very effective and picking a spot close to their haunts and berleying up is a good way to bring the fish to you.

The tricky thing with jacks is that the bait or lure often needs to be put in the most perilous position to entice the fish to leave its cover and strike.

Poppers can be exciting way of fishing for jacks as they launch onto surface lures like mini-barra, but minnow lures to 10cm are more reliable as they work when the fish aren’t as fired up.

Soft plastics fished in close to structure can also be deadly on jacks.

Jacks are more active in the warmer months and when the water heats up places like the Exmouth Marina offer some fun fishing for kids and families for them.

Fishing for them is not an exact science and jacks can be caught on spin or baitcasting gear — heck, some even get caught on handlines.

My favourite way to target the smaller models we usually encounter around Exmouth Gulf is casting lures on lightish spin gear with 5-7kg line that offers a challenge and enables them to show off their fighting capabilities.

I don’t win every battle, but when I do it’s very rewarding!

Mangrove jack can be a formidable foe at nearshore and estuarine areas, just ask Jason Coleman!