Snapper Spawning - something to consider

[bigmack]

Guys - I know you have all been doing pretty well on the knobbies...........as part of the discussion on fish imports/fish farming I found this article about snapper farming and spawn rates. Next time you catch a a bigger fish consider the amount of eggs that a fertile female snapper can potentially produce;

Females spawn repeatedly over a 3 – 4 month spawning season. In a spawning season, a 3 year old
female may produce 250,000 eggs, a 1.5kg female may produce 300,00 to 400,000 eggs and a 10
year old female may produce 5 million eggs.
Fish can mature after 2 years. Mature broodstock are usually held in spawning tanks or floating net
cages, at a sex ratio of 1:1 and a density between 0.5 and 1.5kg/m3. Females with oocytes (eggs
before the completion of maturation) greater than 0.9mm in diameter can be readily induced to ovulate
using hormone induction. Induced spawning techniques using human chorionic gonadotropin (HCG)
are well developed, however, natural spawning produces better quality eggs.

Can anyone on the forum tell me if its possible to identify female sanpper (No its not the ones with lipstick & mascara)

Tx
Phill

[mackmauler]

A spawning closure on the reefs they spawn on for a couple of months Phill is the go, considering there brood stock doesnt do anything for the average punter or a pro out to put 500kg onboard in a night, fisheries are in charge of making the big decisions, as for identifying the bitches the mega ugly ones seem to be males much more often or at least have no eggs, thats an observation of mine with no scientific evidence, the males must play some importance in the whole thing to ay??

[bigmack]

HI MMAuler - the document was very interesting because the fish can change sex. The research seemed to indicate that the fish might be able to do this depending on the need of the stock or independent schools.

I agree that a reef closure would be a good idea or put a size limit on fish like they have for flathead to protect the breeding stock. If you consider that most of us have been pulling reasonable snapper since July last year - then a couple of months closure wouldnt hurt.

It wouldnt be the first time either that I talked to commercial guys at the ramp who bragged about 300 plus kilos of snapper when they were cleaning their dinner of spanner crabs and parrot.

5,000,000 eggs is a lot of potential fish from one fish!

Cheers

[fish2eat]

Very impressive statistics......you would think that releasing just one old female would fix up the stock shortage. However, the percentage that survive to adulthood is extremely small, I doubt that anybody could tell you how many of those eggs would make it to being adult fish, so we'll never know, but it is purely a numbers game.....you'd have to think survival would be less than 1% of eggs laid in the wild.

[Huggy_B]

in perth the snapper spawning area is closed to allow them to "do their thing" so to speak. its a good initiative IMO.

[jeffo]

i reckon they should have a closure on just about all fish at some stage in the year...the way the fishing is getting these days.
one thing i always wonder though, how much stress do we put on a fish bringing it to the boat? will this stress affect the breeding cycle of that fish if it is reading to spawn? (i have thought this aboutt he giant black marlin in cairns)

[rando]

DPI should be breeding ,(growing to optimum survival size) and releasing a couple of million of all our table fish each year.
Weve been hammering these populations for two hundred years, and its only going to get worse.
We should be replacing what we have taken. In ten or twenty years we could have a fishery like " the old days"
I know a bunch of you will say it will create more problems , but if we do nothing all the fisheries will eventually collapse. Remember this , what we have now is a remnant population, without intervention the original populations are gone for good. IMO
rando

[bigmack]

Agree with that! MAFFISH in NZ have been doing this for at least ten years that I know of. Sometimes this country and our government (it doesnt seem to matter which side) are so slow at taking up initiatives like this.

As they said in one of the classics - when there is nothing left to eat - you cant eat the money!!

Phill

[RCG008]

All so true. Talk to the old guys at our local club and stocks are small compared to 15 years ago. Time to act now.

[shaman]

I have read on the net about WA Dept of Fisheries having a ban on Pink Snapper (is that the same as ours??) during spawning season in a particular area (Cockburn Reef) which apparently occurs sept 15 - oct 31. There is also a ban on keeping any fish in excess of 70 cms, this has been happening since 2003!! Where are we??
It is said that snapper spawn on the new moon at flood tide so that their eggs spread quickly and obviously well hidden by the lack of light, makes sense. Apparently this is one reason the Maouri Fising Calender is so successful as this spawning habit is not exclusive to just the snapper. They get hungry just before or just after spawning,I can't remember which. If we remember this and resist the temptation perhaps we as a community can help preserve what stocks we have left & why cant the govt departments work this out and maybe lessen the pressure around these periods? could be a nightmare to try and enforce but that hasn't stopped them in the past, feasible or not.
I agree with you all, at the current rate of decline our fisheries won't be worth a pinch of poop and I don't think that's a long way off.
So we either act now or get used to eating imported sh!t.
Shaman

[bigmack]

Yup - one of the reasons I posted this was because of the unbelievable snapper season we have had here on the Sunshine Coast - it seems that every person who goes to the banks when conditions allow - just about bag out. Occassionally people dip out - but the expectation seems to be bag outs every time. Consequently the banks area is getting a hammering and last weekend they called it the Barwon Banks Marina - in fact there are so many boats out there and overnighting that Im thinking of buying a trawler and anchoring out there with a card table, barmaids, fridges and some comfy beds and you guys can all raft up and be entertained (LOL)

Anyway - here are the questions to those who have fished the banks for a long time.............?
1. Is this season great by comparison to others?
2. How much more traffic is there at the BB's?
3. Can it continue at this level & remember that not all people who fish out there post to Ausfish and tell you how well they did?
4. The fish have been on for 9 months? Since winter............Is this unusual
5. DO you see any commercial fishing on the banks for snapper - is longlining allowed?
6. If the spawning fish have been and gone - are these resident fish or travelling schools?

Interested in your observations

Phill

[browndog]

bigmack i have fished the barwons since 1990 and must say this has been the best snapper season that i can remember.Soon as people start catching fish the rumblings begin and the calls are made that the banks is screwed.
The amount of boats has not changed dramatically but the boats seem to be travelling further north for there fish.I am sure any part of the banks can produce good catches of fish if they know where to go.
Nature has a way of balancing itself,we went through years of 30 snapper per person and we now have the best season ever.We have just come off 5 weeks of bad weather where no one has been out.
The early 90,s we had a lot more periods of calm weather with variable winds,not any more and we still have the snapper in plague proportions.
Its only through more people joining this site that the catches are now being seen.These catches have been happening but not getting the media coverage they do these days.
We now have more fishing mags,tv shows and radio programs that give advice on how to catch more fish and bigger fish not many articles do i see that tell us to fish for the future.
Iam not sure if the snapper come off the shelf or travel up from south waters but perhaps there has been a weather,current or temperature change in the water which may have an effect on the fish.
Have fished with commercial or pro fishermen,line fishing.They make a living but arent rolling in cash.One good week 5 bad,no money for 5 weeks not good.
My opinion is that the barwon banks will still be fishing well in another 15 years and beyond.
Cheers browndog

[fish_outta_water]

hi guys quick note related to your thread here ,(more detailed info in marlin magazine) its becoming apparent in studies around the world that taking the larger (specimen ) fish out of our fisheries is having an effect on stock size as the fitter larger fish spawn and produce fry capable of faster growth + larger potential size. so removing these specimen spawners over a period of 200 years leaves you with a weaked gene pool (smaller records slower growth)
tightlines

[efc]

I think that pointing the finger at the DPI is counter-productive!
As fishermen (and women) and human beings it should be your initiative to throw back the large snapper. It must be a macho thing to kill and eat the one with the biggest knobby head or the best colouring?

After seeing all the pictures in the forum off mass slaughters you have to wonder how long the brood stock can continue populating their environment.

Be a true fisho and limit your catch...DON'T catch your limit!

[szopen]

Can I add a bit from a different point of view.


As correctly stated bigger fish will be able to lay (fertilize) a larger amount of eggs.

Well the problem with this type of reasoning is that when you take into account the size curve of any animal (humans included) population you will find that there are much more smaller fish than bigger ones.

I for arguments sake a 1m fish can produce 1000 fertilized eggs and a 50cm one can produce only 200 but with the population average size 50cm fish outnumber 1m fish 50 to one it will be 50cm fish contributing more to sustainability of population.


In saying all of the above I belive that it is the combination of size, bag, closed season limits than can have a biggest effect on sustaining the population as whole.

Where I come from the fishing is tightly regulated with minimum sizes ansuring that the fish will spawn at least once, bag limits and closed seasons during the spawning season for various species.

Seems to work. Under much greater fishing pressure than you can imagine in Oz.

Same applies to hunting.

It is by understanding how the animals population behaves when faced with pressure that helps preserve it.

From what I have read on this site I would guess that it was change in bag limits to 5 fish that really made the difference.