male or female flattie's

[Blaster Bretty]

Ok bloke's and blokette's, I have been living under a rock for quite some time and I see an awfull lot of ranting + raving about peep's saying things like...."I caught and released a huge female Flattie" or it might be...."I caught 2 male flattie's and 3 female's but the female's were thrown back".
So my question tonight will be......How do you tell the difference between a female and male flathead???
I myself have only ever caught 2 flatties, 1@40cm and the other @43cm, as a consequence they were caught on separate days and by accident as I was fishing for bream. and both were eaten as I will eat what I catch on the day and do not catch heaps and heaps of fish to store away, catch and release is practised but more to the point of it all..... how do I tell the difference between female and male flattie's.
Please help.

Bretty

[wayno60]

i dont know about flatties but with a lot of aquarium fish, and not going by colour differences, you vent sex fish., males have a more rounded vent where the fems are oval shape....
i also found this
Why do we have size limits?

In Queensland, there are limits on the size of #sh that can be legally taken for many species. There are minimum size limits and also some maximum size limits.
Size limits are typically based on biological research into each species' reproductive cycles. Minimum size limits generally allow #sh to spawn at least once and contribute to the population before they are taken.
However, in some species larger individuals contribute more to the population, which is why maximum size limits apply. For example, most barramundi begin their lives as males and later, as they grow larger, become females. A maximum size limit is applied to protect large females and to allow them to spawn.

[tunaticer]

Brett,
From what I understand nearly every flathead over 70cm is female. Males apparently do not grow in excess of 70cm as a rule.

Jack.

[xrnath]

Brett,
From what I understand nearly every flathead over 70cm is female. Males apparently do not grow in excess of 70cm as a rule.

Jack.

That's what I believe too.. studies have found that the largest males rarely exceed 65cm :)
There was also some speculation a while back that Flatheads (mainly Dusky) were hermaphroditic?
Without cutting one open to view the gonad (by then of course is too late), there's no visible signs to my knowledge... however I would also like to know more ;)

[Cammy]

Thats interesting, males apparently dont grow more than 70cm.... would also liek to hear more.

Cam

[reel scream]

There was also some speculation a while back that Flatheads (mainly Dusky) were hermaphroditic?


Heard similar in that males turned to females once they reached a certain size. ? Barra do the same.

Here's a thought- maybe thats why men grow man boobs once a certain size;D .

Cheers Scott

[reidy]

There was an intereresting thread sometime back with regards to flattie sexes.
If my memory serves me there was some debate with regards to 700mm+ flatties all being female as some southern off shore fish didnt fit this model.
Cant remember the exact thread title but its about somewhere.
Cheers
Reidy

[coucho]

Dusky Flathead and as far as i am aware tiger flatties too don't change sex the females just grow larger and faster then males very hard to tell the sex without running a knife through.
males never grow much larger the about 50cm and females don't reach sexual maturity until around 40-50 cm the larger females produce more and healthier offspring which is why you should let them go

[Outsider1]

From the research I have read, there is no evidence that Dusky Flathead change sex at any time in their lifecycle.

The research suggests, as Coucho has mentioned, that female flathead reach sexual maturity at about 45cm and 3 years of age. From samplings females make up a large percentage of fish over 50cm. Females also grow to a larger size and at a faster rate than males.

Females also apparently produce more eggs are they grow larger.

Here is a sample of some research on the Flathead fishery. I have copied some relevant paragraphs. See page 7;

http://209.85.173.104/search?q=cache:mqeTPHpMTW4J:www2.dpi.qld.gov.au/extra/pdf/fishweb/inshore_dart_grunter.pdf+flathead+lifecycle&hl=en&ct=clnk&cd=1&gl=au&client=firefox-a

Cheers

Dave

[Gorey1]

I'd like to know how to tell the difference when a flathead is smaller than 70cm. Sure you can assume a 70+ is female but what about a 50cm fish? It's terrible when you cut open a legal fish to find eggs. I'd rather throw all the females back just in case.
Is there different colouring or shape etc. to look for?

[Outsider1]

I'd like to know how to tell the difference when a flathead is smaller than 70cm. Sure you can assume a 70+ is female but what about a 50cm fish? It's terrible when you cut open a legal fish to find eggs. I'd rather throw all the females back just in case.
Is there different colouring or shape etc. to look for?

No obvious distinguishing features as far as I have been able research so far.

Size is probably the only rough guide, 45cm or less and it is more likely to be a male. "From samplings females make up a large percentage of fish over 50cm".

Time of the year could also offer some hints, between September and March when they are said to spawn, a "fat" larger fish is probably a female.

The other thing to realise is that the bigger they get, the greater number of eggs they produce. A 90 cm female could be producing 10 times the number of eggs of a 50cm female. So letting them go over say 50 or 60cm is probably a good "line in the sand". Unless you want to stop targetting them completely, or at least when they are spawning!

I think the current slot sizes in Qld are probably pretty close to very good science. Certainly the anecdotal information since the slot sizes were introduced is that Flatties have made a very strong comeback in hard fished waters around the Gold Coast.

Cheers

Dave

[GBC]

Betty,

Boys have banannywhackers hanging down
Girls don't

[DR]

here's a bit of background, just scroll down to the flatties
http://www2.dpi.qld.gov.au/extra/pdf/fishweb/inshore_dart_grunter.pdf

[Lovey80]

Her is the Flattie thread i think a few were refering to. I started it in Jan this year. Basically as far as dusky flathead go males don't reach the 70cm mark so anything over that is confirmed as a female. I too believe that flathead have made a good comback since the bracket size limmit was introduced

http://www.ausfish.com.au/vforum/showthread.php?t=123511&highlight=flathead+lovey80

Cheers

Chris

[Scott nthQld]

There used to be a lot of hype that flatties, like barra, would change sex when they reached a certain size, but as we know now, not true.

I don't think there is a way to tell the males from females from any external physical attributes, so if keeping them between the slot size limits its mainly luck of the draw, I've caught them in the low 40's, only to open them up and find out the were indeed female and full of roe.

I guess the benefit by having the slot size limits is that it helps prevent the taking of the brood stock, but still allows kids and the like to take a 60-70cm fish (which is huge to them) home and reap the praise and pat on the back from mum and dad. Personally, I don't go much on big flathead on the plate, like most fish, the bigger they are, the the more the table quality goes down, I'd rather take home 4-5 45cm flatties for a feed or 2 than take home 1-2 69.9999cm flatties.

[Blaster Bretty]

thanks to all that have replied.
I guess at the end of it all scott's last post on this thread really does sum it up.
I suppose the debate will rage on however but it's a question I really needed an answer to ,due to the fact I will be targeting the flattie over the next 2 weeks (nugget's club comp you see) and I really was hopeing that if I was lucky enough to nab a couple then I would of been able to tell if they were he's or she's with the later going back of course.
once again thanks to all, I got the idea of it now.
Cheer's

Bretty