From the North Coast of NSW right up to the Cape, Mangrove Jacks are a favourite target species for many anglers. They can be very challenging with many fisho’s getting bricked in the first few seconds of a hookup. They smash lures readily and fight really hard making them a very worthy adversary. They also happen to taste really good too.
Its takes around 6-8 years for a female Jack to reach maturity at which time they can make their way out to offshore reefs to spawn. Reef Jacks can grow over a metre! They also live well over 40 years!
So do you kill them for a feed or release them? Out of all estuary species, Jack’s in my opinion should be released every time. Why? Well over the years I've heard many reports of fisho’s finding a fallen tree somewhere up an estuary covered in Jacks. They fish it for a few weeks and kill every fish they catch and after that there’s simply no Jacks to catch in that location.
Jack’s are very territorial and some studies have shown that even when released many kilometres down river they still return to their family snag. So if you keep all the Jacks off a particular snag you're really just wiping out an entire family. Some of these Jacks could be 20, 30 or even 40 years old! I think more research is needed on Mangrove Jacks as they really are a very cool fish that I hope to be able to keep catching for years to come in my local estuary.
With all that said I’ve kept many Jacks for a feed when fishing in the tropics as some of those schools have hundreds in them and I know the impact is very minimal. I guess it’s a numbers game. They are certainly far less prominent the further South you go so maybe we should all think twice about necking one for a feed. Catch a few Flathead maybe!!! ;-)