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Yeh they have released heaps of papers on jacks but all of the ones i have read so far have been based on aquaculture and pellet feed formulations.Originally Posted by ozvettec1
Another source of possible info. is AIMS, Australian Institute of Marine Science, based in Townsville. I work for the CSIRO and have visited this facility on occassion, perhaps there website may have more info.
Yeh they have released heaps of papers on jacks but all of the ones i have read so far have been based on aquaculture and pellet feed formulations.
Sorry for the late reply guys and gals but i've been away from civilisation for a few days.
I was always under the understanding that Jacks once they got to that certain size they left for the reef and left all thier breeding behind them. I couldn't imagine the breeding and spawning done in open water and then the fingerlings making their way to the estuaries. Maybe I had it wrong all this time but if I am correct then making a comparison with flathead wouldn't be too accurate a guage as the Flatty are all male until around that 70cm size and after that they are the female breeders.
As soon as this post is entered im leaving for the wide bay area chasing them so i won't reply again quickly until monday but does anyone have a definite answer on the breeding cycle/sizes of MJ's????
Any help is greatly appreciated.
Cheers Chris
Democracy: Simply a system that allows the 51% to steal from the other 49%.
I have read and been told over the years that once they reach a certain size they leave to go breed, of cource some stay behind in the rivers maybe there late bloomers who knows, but once they reach that 50cm size they start heading for the mouths of the rivers thats why at the end of summer you here people catching big ones around the sea way cause they school up at the mouths of the rivers and then head for the reefs and so on to breed and grow up,not or the baby jacks make it back to the rivers once born some stay out on the reefs for ever some get swept back to the rivers, but im almost 100% sure they breed out on the reefs and not in the rivers and why would they breed when there 30-40cm there still youngens, there breeders once they reach a certain size and head for the reefs .cheers
Last edited by jackextracter; 13-09-2007 at 11:29 AM.
Lovey , My understanding on both fish is different, but I'll leave it to someone more knowledgeable to set us both straight
Lovey My understanding on flathead is that a fish under about 40 cm could be M or F, over that they are F, as M pretty much stop growing at that size. The only fish around here that are into sex change are Barra, but I could be wrong.
Just found this on the net it tells you about there breeding and migration.
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There has been little research on this species and all we know about jacks' breeding is that they lay their eggs in open water during summer and given that the mature fish live on the offshore reefs it is assumed that breeding takes place there. Jacks reach sexual maturity at four to eight years and at about 55cm in length. Their lifespan is an amazingly long 32 years and more recent indications from research is that they may live as long as 45 to 50 years. This generally means that the jacks encountered by recreational anglers in northern creeks and around mangroves are immature specimens. They feed on prawns and crabs and just about any fish they can fit in their cavernous mouths. However, they are reluctant to leave their lair, preferring to lie in wait and ambush prey that passes with the changing tides.
Last edited by jackextracter; 13-09-2007 at 11:45 AM.
some more info.
Description
Mangrove jack are energetic and powerful fighters. They reach weights of up to 16kg (150cm). They reach maturity in just over 3 years, and they are 54-55cm in length at this stage. Young fish are generally uniformly reddish-brown or copper coloured, becoming paler in reef waters and often with a pearly mark in the centre of each scale. Colour may vary depending on a particular habitat. Reef fish tend to be lighter and brighter than fish caught in estuaries. Mangrove jack are also known as red bream or even dog bream due to the sharp dog-like teeth in their upper jaw.
Habitat/distribution
Mangrove jack are marine fish, however juveniles commonly enter mangrove estuaries and rivers to the extent of the tidal influence. Adults prefer sheltered inshore coral reefs, especially offshore trawling grounds to depths of 120m and heavily silted areas. They are widely distributed in both estuaries and reef waters along the Queensland coast and the Great Barrier Reef. They also range into northern New South Wales, the Northern Territory and north-west Western Australia.
Jack could U repost that web site
http://www.westernangler.com.au/defa...article&ID=160
the first info was from here the second lot come from the dpi
http://www2.dpi.qld.gov.au/fishweb/2194.html
Last edited by jackextracter; 13-09-2007 at 12:21 PM.
i dont think they need a bag limit, you might catch 1 or maybe 2 jacks in a session, especially in SEQ, how often is it you catch between 2 and 5 mj's. even up here in nq more 6 or 7 jacks in a morning is unusual. there is no shortage of them, they are just eluseive, i have a few contacts that do alot of spear fishing that say they do school up in numbers of about a half a dozen or so, around head lands they form bigger shcools, they are a very wize fish and cotton on to whats going on very quickly. thats why you dont catch big numbers of them.
cheers chris
Gippsy (cgg81)
Cant you catch more than one or 2 in a session!!!You told me you were a better fisho than that!!!
l have to show you how its done when we get to Hinchenbrook next week
STEVO
BTW thanks for that info jackextracor. very interesting. A 35 year old MJ !!! bet that would be a cranky fish
Last edited by cdg81; 13-09-2007 at 08:50 PM.
DPI website only reflects current bag limits.
DPI are always reviewing certain species, and are in discussions with Sunfish and csiro to review jacks. they made a suggested bag limit of 2, and discuss this for some time. Jacks are currently under review, it was in Band B or QFM a few months ago. They also looked at raising the min length to 38cm, but I reckon this will not get approved.
Its not a firm decision yet, but I wouldnt be suprised if a limit of 2 comes in in the next year or so.
Im not sure if I agree or disagree with this. I just wanted to point out the process was already rolling on.
I would prefer to see more ausfishers join sunfish tagging programme. Then we could get more info on jacks habits. jacks are currently on teh tagging list, and theyre not getting enough info. C and R is not enough. What about tag and release boys?
cheers
ANdrew
I would prefer to see more ausfishers join sunfish tagging programme.
How do we get involved, Andrew?
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