Snapper Stocks - Another View

[Timfishin4fun]

Damn you man, I promised myself I would not respond any more!

Statistics are a great thing. I use statistic to make sure you lose your money at the pokies! Well not quite true, but the punter gets back around 90% of what he/she puts in. The house keeps 10%.

Now I may not have a lot of data on those statistics, but we use models to predict the outcome. When you first start off, you have little data, but you can glean some info out of it to get an idea of the result. The more data we put in, the better the result, and the less error we get. So it may go from 40/60 to 30/70 in your favour. Of course, it can go the other way too, it could end up 50/50. After 500000 samples it becomes very accurate, and the uncertainty is minimal. The modelling is not incorrect, in fact it is the total opposite, its very accurate. However to reduce the uncertainty, you need to obtain more data.

Pokies are totally random. So how do we get the stats on them? Simple, once again we use modelling to figure out all the combinations that are possible, and apply that to another model to come up with an answer. Same applies to lottery, keno or any other form of gambling. You can also apply the same theory to fish biomass, however this is when it starts to get specific and I can eleaborate on that.

Because we dont have enough data initially, we have to quantify the error and uncertainty. Thats the part that the snapper assesment reviewers are talking about, and infact the authors of the snapper assesment also discuss this.

So to express the uncertainty in figures, what we then do is model using worst case examples at both extremes. This information is all available in the snapper assesment.

The only way then to reinforce that model is by adding more data. Hopefully it goes the otherway, and our stocks are still good. But from what the DPI guys have to work with now it does not look good. Modelling using extremes based on rec input also looks grim.

How did I go? AM I getting there? BTW. I am adding this info to a document I am writing to try and explain the whole concept in simple terms.

I think what Andy is trying to say is that with the figures supplied from the rec fishers from the alleged phone survey that the modelling used 400odd tonne of snapper is easily achievable.

Models such as these can easily be used from industry to industry to provide valuable info wether it makes someone money or calculates fish caught.

The problem comes from where the info has come from. I could do another phone survey and come out with very low figures. But what if the two were put together we would get a more average figure.

Now if the figures they have are even from a true survey and not doctored, I'm not sure of that as I don't trust them. And I believe alot of reco's don't either.

So what info should we give them, figures that make a high scenario apparently do not state stocks are fine but we are over fishing, and too low say stocks are down and not that seasons are not right or the fisho's used don't catch many fish. And once bitten twice shy comes to mind.

All this makes it very hard to assatain a true figure of stocks no matter how good the modelling is.

Where to from here? I think in our democracy we are doomed. They will tell us what is best for us. And will it be the end? No way! Once one species is not targeted they will say another stock is being fished to extinction.

But I really do appreciate the help and fighting from the guys out there. The amount of personal time these guys put in is astounding.


Timbo

[Lovey80]

So what info should we give them, figures that make a high scenario apparently do not state stocks are fine but we are over fishing, and too low say stocks are down and not that seasons are not right or the fisho's used don't catch many fish. And once bitten twice shy comes to mind.

Your 100% right on that one. I guess that's what I was trying to say a while back. They have a double edged sword to gut us with no matter what the Rec Data does show with proper data collection.

Because they have made up their minds that they have some miracle model that tells them that Snapper are below 40% of Virgin no matter what the Rec Data ( if comprehensively collected) shows it will be the reason for the low Biomass!

As far as I am concerned there is only one comprehensive way to determine if Snapper stocks are getting better or worse with the list below.

1. Start a comprehensive Rec Data collection (mandatory) and give it 5 full years of collection to form a pattern. Take into consideration all the other factors that will effect catches-weather etc. These variables should be the only ones allowed to be considered during the first 5 year "test sample" for lack of a better word.

2. No closures, TACs or change to size and bag limits until the first 5 years is up. If you do then your going to taint your "test sample" and they will effect the results.

3. After 5 years the Data from all three sectors should be easily modelled to determine what measures need to be taken.

4. From there simply by the amount we catch should be the best indicator of if the fishery is improving or declining and if our measures are working. Pretty simple really, everyones catching consistently more fish = everybody happy, the opposite then we bring in more measures.

I am the first one to admit that just because you don't catch fish doesn't mean they are not there but if your going to put measures in place get the goal right first. The goal isn't to satisfy some international 40% figure the goal is that Queenslanders catch more fish sustainably for ever. It's our resourse and measures are to be put in place to benefit all of us.

Just my thoughts.

[Lovey80]

There is one thing I would love to know though about this so called Biomass wonder model.

What would the model say the percentage of unfished Biomass was remaining in say 1995, pre all the current size and bag limits.?

Was it down somewhere between 25 and 30%, and the 30cm x 5 has brought it up to 35+/-% but this is too slow and we want to get it above 40% faster?

Or was it somewhere around 40-45% and all the last restrictions did was slow the decline?

Also what is the actual goal of this whole Assessment? Is it just to get us over the 40% mark are these options suppose to get us up to 60-70-80% over ten years?

Once we get to whatever % they decide on have they got a set of regulations ready to go once we hit that % so that we don't decline again? Or

Do they intend to keep us at 260t/400t total for ever? I know they are saying 400t total is to rebuild the Stocks but at what % to what total TAC (all three) keeps that % constant?

There we go Constant ( different use of the word ) was the word I was looking for to describe our first 5 year "test sample".

[TheRealAndy]

There is one thing I would love to know though about this so called Biomass wonder model.

What would the model say the percentage of unfished Biomass was remaining in say 1995, pre all the current size and bag limits.?

Was it down somewhere between 25 and 30%, and the 30cm x 5 has brought it up to 35+/-% but this is too slow and we want to get it above 40% faster?

Or was it somewhere around 40-45% and all the last restrictions did was slow the decline?

Also what is the actual goal of this whole Assessment? Is it just to get us over the 40% mark are these options suppose to get us up to 60-70-80% over ten years?

Once we get to whatever % they decide on have they got a set of regulations ready to go once we hit that % so that we don't decline again? Or

Do they intend to keep us at 260t/400t total for ever? I know they are saying 400t total is to rebuild the Stocks but at what % to what total TAC (all three) keeps that % constant?

There we go Constant ( different use of the word ) was the word I was looking for to describe our first 5 year "test sample".

The virgin biomass uses data going back to 1945. This figure is not in question, the rec take is.

[Lovey80]

The virgin biomass uses data going back to 1945. This figure is not in question, the rec take is.

That still doesnt answer my questions. I would like to know if the model can tell us if the fishery has improved at all over the years since size and bag limits changed or mearly slowed the decline?

Also the goal questions I had?

Any thoughts?

[TheRealAndy]

That still doesnt answer my questions. I would like to know if the model can tell us if the fishery has improved at all over the years since size and bag limits changed or mearly slowed the decline?

Also the goal questions I had?

Any thoughts?

You will have to forgive me, because i cant quote exact figures.

However the increased size limit did show a small increase in biomass in the couple of years after introduction, but shows a decline not long after. I cant give exact figures, but maybe Bill and Barry can step in here with a bit more info.

Bag limits where not really an issue as only a small percentage of fisherman actually manage to reach the bag limit.

[dayoo]

You will have to forgive me, because i cant quote exact figures.

However the increased size limit did show a small increase in biomass in the couple of years after introduction, but shows a decline not long after. I cant give exact figures, but maybe Bill and Barry can step in here with a bit more info.

Bag limits where not really an issue as only a small percentage of fisherman actually manage to reach the bag limit.

The past increase in snapper minimum size to 35cm did stop the decline of snapper stocks but only marginally for two years then the decline continued according to the modelling input data. There was a graph in the original snapper stock assessment that highlited this but I threw all my papers in the garbage bin in disgust when I read the RIS.

Fisheries are concerned that if TAC's or closures are not introduced quickly then the sustainability of snapper in SEQ may drop past the point of no return.

The measures mentioned by Lovely80 will take another 5 years and if after that time elapsed we find that the recreational take is over the Fisheries estimates then the fishery will truely be in trouble. That is why I have suggested a review after 1 or 2 years of data collection measured against the notational TAC of 260 tonnes.

Cheers
Barry

[Lovey80]

Thanks Barry,

Do you recall or was it mentioned what the target % of unfished Biomass was or was it just "above 40%"?

Also will the TACs remain after 10 years or is our current size and bags deemed appropriate once the Biomass is larger? Did they mention what the plan was to maintain the new "healthier" level once reached?

[dayoo]

Thanks Barry,

Do you recall or was it mentioned what the target % of unfished Biomass was or was it just "above 40%"?

Also will the TACs remain after 10 years or is our current size and bags deemed appropriate once the Biomass is larger? Did they mention what the plan was to maintain the new "healthier" level once reached?

The target % of unfished biomas was above 40%.

As I understand Fisheries will monitor the tonnage taken by all sectors and there will be a review of this data after a couple of years. If the recreational tonnage is in excess of the notational TAC then other measures to rebuild stocks may be considered. If tonnage is below the TAC then there would be no reason to introduce any further restrictions. In my opinion the need for a TAC could be reviewed after the 10 year period and other methods introduced to keep the biomass above 40% of unfished biomass (e.g. increase in min size to 40cm and or in possession limits on larger snapper over 70 cm).

Cheers
Barry

[FISHAWN]

BTW, I disagree with the science, but I have seen it. How many here have?

If you disagree with 'the science' (as you stated at the top of page 2 of this thread) why have you been arguing for it ?

[TheRealAndy]

If you disagree with 'the science' (as you stated at the top of page 2 of this thread) why have you been arguing for it ?

Poor choice of words. I disagree with the figure (400t) they are touting.

[Lovey80]

Andy,

Am I so far off the mark right now to suggest that if the 400t mark that fisheries have come up with could be wrong then the "data" going back to 1945 could also be wrong?

How many assumptions have been made to extrapolate data going back that far to get a wholistic approach to build a model of this size? How much error could be in these assumptions??????

[TheRealAndy]

Andy,

Am I so far off the mark right now to suggest that if the 400t mark that fisheries have come up with could be wrong then the "data" going back to 1945 could also be wrong?

How many assumptions have been made to extrapolate data going back that far to get a wholistic approach to build a model of this size? How much error could be in these assumptions??????

I suggest you read this document here: http://www.dpi.qld.gov.au/documents/...6-Complete.pdf

I have already expressed my views, and the 2009 assessment by Campbell et al, refers mainly to this doc.

Edit. I just want to add that I am still stunned that no one has picked up on one key aspect of that document, perhaps because no one has actually read it. I shall remain silent on it for now, because I want people to look at it, and try and understand it at a high level.

[castlemaine]

Andy is taking a battering here but as a previous member of Ecofishers Qld he and others did make a difference in the last election ... got Labor to see the fishing vote can make a difference. This is what we should be concentrating on. LNP get off your arse and get some fortitude and support the real issues and you will get some real voters.
This is my take ...
Science (I am of QUT Science background), first you make a hypothesis then you prove this hypothesis right or wrong ... not presumed on unsubstantiated or best available data. Fisheries science is wrong if it is on presumed or best available data.
Andy, Barry, Bill and others that have worked so hard on the rec side to get us a fair deal, hope you don't blame this division, when the final decision by fisheries is brought down and we are screwed, as I and I suspect many others feel, we will be screwed anyway ... because the decision has already been made.
Cheers, Ivan

[caster226]

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