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Fitzy
24-01-2002, 09:57 PM
A breakthrough in research into the captive breeding of mangrove jack should give Queensland’s anglers another reason to celebrate this festive season.

Fisheries scientists at the Department of Primary Industries believe they have discovered the secret of breeding mangrove jack fingerlings by the thousands.

These tiny fish will be used to restock Queensland’s popular freshwater fisheries, in the same way as the hugely successful barramundi restocking program.

"Anglers will have the opportunity to fish for mangrove jack in local dams– and perhaps hook one that rivals the size of adults that occur naturally only in off-shore waters," Cairns-based DPI senior fisheries scientist Dr Mike Rimmer said.

DPI scientists have conducted the mangrove jack breeding research project for the past seven years. A notoriously aggressive fish, breeding stock placed in tanks during the early stages of research spent their time "beating each other up" rather than in more romantic pursuits.

A visit to Taiwan, a major hub of Asia-Pacific aquaculture, by Dr Rimmer caused a rethink in strategy – and the trial of a mangrove jack "love nest" in ponds at DPI’s Townsville research facility.

"In Taiwan the fish were held in ponds rather than tanks, with the brood stock kept in enclosures until spawning occurs. A fine mesh net that acts as the walls of the enclosure ensures no eggs are lost.

"The eggs are then transferred into an adjacent rearing enclosure where they are reared for five days until they are large enough to be released into the pond. Food for the larvae, specially bred microscopic crustaceans, are also transferred into the enclosure. Once they are released into the pond, they take another 3-4 weeks to reach fingerling size (about 30 mm)."

The first trial of this new breeding method, conducted in November, produced 4,000 mangrove jack fingerling. The previous best was 1,500.

"With some more refinement of this method and some technical changes, we’re hopeful that we can breed 10,000 or more mangrove jack fingerlings at a time. These fingerlings will be used in stock enhancement programs across the state. It’s also intended to make this breeding technology available to Queensland fish farms," Dr Rimmer said.

Further information: Dr Mike Rimmer Fisheries scientist Ph: 40 350 100 Andrea Corby Media Officer NQ Ph: 47 222 648 mobile 042 878 3441

;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D ;D

Cremated_Reddog
25-01-2002, 05:19 PM
hiya fitzy, like you know I know stuff all about the Qld fish stocking programms and the breeding side of things but this sounds like a good thing for everyone involved and concerned... mate will have to get my butt of the ground and come join some of these fish stocking groups.....

Simon
26-01-2002, 01:28 PM
God help all those noxious fish in all the eastern impoundments, Jacks can make an impact if their numbers come good.

Cheers

Simon

jack_attack
17-08-2002, 07:16 PM
Is there any indication as to which dams will be stocked with jacks?

Will the introduction of jacks cause any conflict with other stocked fish? I mean a big jack is going to want to eat big meals, if not it will eat a lot of small ones. What is it going to do to the Bass fishery that Qld is so famous for.

Will Jacks actually eat the noxious species?

A lot of questions, does any one have the answers? Or is it all guess work at the moment?

I for one certainly hope that they do end up stocked in to some local dams. Just imagine how fast they will grow and how big they will get with all that food in there, and with them being the top of the food chain.

Who is going to be the first person to use a 1 kilo plus bass as a livie?

landy1
17-08-2002, 07:30 PM
g'day all
wow, having seen how big jacks grow out on those reefs i dont htink ill be swimming in dams that much longer. :o the concept of these buggers in dams just defies me at the moment. without trying to raise feathers, fully grown impoundment jacks would crap all over barra. catfish beware.
cheers

StuH
18-08-2002, 03:15 AM
How would they go in the inland dams of Central Qld, like Fairbairn dam at Emerald which badly needs a stocking program.
And what could be better then Jacks? ;D ;D
If the growth rates of Awoonga are any indication you could have a top fishery in under 2 years.

Stu.

Simon
18-08-2002, 04:43 AM
As I understand it most dams/stocking groups will not be able to stock Jacks into their dams due to their proximity to the coast and how and where the remaining river flows and it current ecosystem. I think the only Dams in Sth East Qld that will be elligible shall be Hinze and North Pine. but it is still early days yet. Atleast the rivers shall get a good boost if they are healthy enough.

Cheers

Simon.

lordy
19-08-2002, 04:37 PM
We are hoping to get jacks for Wivenhoe, though Somerset isn't looking so promising. It may still be a long way off and a few fights away but we are certainly going to try our hardest.

Size, yes hold on for dear life, they may/will get to huge proportions in dams.

Will they eat the bass? Unknown, it will depend on whether they stay structure orientated or go pelagic like schooling bass. Its possible they may have an adverse effect on bass. But if they do, with so many bass dams around it won't matter. I'd love to see fishing for for Jacks in Wivenhoe and bass in Somerset. Nice combo.

Fitzy
20-08-2002, 06:20 AM
Fish eat fish, that's their very nature. Im sure that bass eat bass, yellowbelly eat bass, bass eat yellowbelly etc etc
We stock Mary River cod, they definately eat bass. Last year a 10 kg cod from Somerset wouldn't swim away when released so its stomach contents were examined, it has 3 bass in its gut.
So to minority of wowsers & wankers who are worried about fish getting eaten by barras or jacks WAKE UP & SMELL THE COFFEE, it already happens with what we stock now.

How about we simply stop stocking bass in Wivenhoe, then there'll be nothing to worry about. ::)


Fitzy..

jack_attack
20-08-2002, 01:41 PM
It seems a bit strange that Jacks may be aloud to be stocked in to Wivenhoe but not Somerset. Personally, I would like to see them in all the dams. The more jacks there are around the better.

Do I take it that there is nothing concrete about the stocking of jacks? Any one have an idea of a time frame of when they will be available for stocking? Is there some thing we can do to help it along?

Brett_Finger
21-08-2002, 05:52 PM
Fitzy,
mate i have to tell you, the thought of Jacks in the ponds excites me!!!!!
the grouth rate so far from the studdies indicate an excelerated grouth to impoundment fish as opposed to jacks in "the wild" this will start sorting out the boys with the light Perchin gear !!!
a 4kg jack or bigger on light perch gear.... YEEEEEEEE HAAAAAAAAA
Hookin,TBF ;)

MikeC
03-09-2002, 06:20 AM
Fitzy - I'm not too sure it's fair to refer to the more cautious members of the fishing fraternity as 'wowsers' ans 'wankers'! We have a great bass fishery here and it's worth preserving, surely! Perhaps you'd argue that there are already more bass swimming around in SEQ than Nature ever intended, but by the sound of things that will also be the case with mangrove jacks.
No doubt someone somewhere knows the optimal stocking level for each and every dam. I just hope they find the correct balance. Jacks would be a fabulous addition to the freshwater fishery, just as jungle perch would be. As much as I love catching bass it adds another dimension to fishing when you can't nominate with certainty what's on the other end of the line. That's the case of course in Clarrie Hall, and while I understand and support their thinking, I sure hope that one day they put some cod in there. And yes I DO know they eat bass.
But getting back to the point - we sure are spoilt these days. When I first fished for bass back in the late60's- and no, I'm NOT trying to sound like an old sage who knows better than anyone else - it was a thrill to have a fish so much as BUMP your lure, never mind catching one! Nowadays we can catch bass to several kilos and STILL it's not enough! We want more. Will the SIP cover the cost of the jacks??? Does it even cover the costs now?? HAH!! Will other species numbers suffer as a result? Hopefully those who know about optimal stocking rates can answer that, and again hopefully they can produce a good balance.
I consider myself to be neither a '######' nor a 'wowser' - but maybe blindness is a trait of such people ;D - however I remember what it's like to go a whole bass season without catching a single fish, and I cherish the fishery we have today.
Mike

Fitzy
03-09-2002, 04:14 PM
Hi Neil,
While I certainly didn't name names, there certainly are some wowsers & wankers out there with hidden agendas. If you, in my comments, see a hat floating & put your head into it that's your choice. Each to their own I suppose.
The precautionary principle gets flung around far too easily these days. Why do some folks endorse this policy without question on the one hand, and then openly allow exemtions with the other? Take a look at the stocking of Murray/Darling sepcies on the eastern side of the Great Divide. It's rather hypocritical from my persective. I don't care either way, I'll continue to work towards a brighter angling future for everyone & if that means stepping on a few toes, then bully beef for them. But let's at least some consistency in policy.

Me? Well I personally believe that we are yet to approach the potential of many of our stocked lakes. Why not use these (previously almost devoid of fish) water bodies for recreational use? Some may enjoy catching a feed, others may enjoy some sportsfishing or C&R fishing, again, each to their own.
I too have enjoyed the pre-stocking wild bass fishing, it's not an exclusive club. Used to get rather excited about getting a 30 cm fish back then, now we call it a rat.
Yes, there could well be more bass in many waterways these days, there is also several million mega litres more water for fish to live in as well in the form of lakes. Along with these lakes come the massive protein sources for medium & apex predators to eat.
I'm not so blindly wrapped up in bass & bass fishing to see that many other species are worthy of stocking for all types of anglers to enjoy. I believe stocking groups should (most do anyway) take this into consideration when deciding upon numbers of fish to be stocked & what species. I'd be willing to give up bass in one or two SEQ locations to see one or two Jungle Perch & Jack locations pop-up. Anglers can only be winners by this happening.
Stocking density levels? All stocking groups operate within QFS guidelines. If these are incorrect for any given location, then it is QFS than need to wear the responsibility for this.

Cheers,

Fitzy..