Snapper Stock Assessment-My thoughts

[honda900]

Given your answer Andy,

I will assume you know where this came from.. just a differing view on the data provided.

· This stock assessment used a series of statistical analyses (generalised linear modelling, SALSA and SSRA population Models) to investigate to what extent, if any, the stock is overfished.
· Catch rates from the commercial sector were stable over time, appearing to indicate a low impact of fishing.
· Howerver, there are concerns that the commercial data were hyperstable (catch rates can remain stable while abundance is declining), and this concern is supported by charter data and two recreational data sources, which all showed consistent significant declines.
· Model uncertainties
· Although the best available data were used to determine the status of the stock, there was an inherent level of uncertainty associated with the data and model assumptions. Major levels of uncertainty exist in the key biological parameters of natural mortality and stock–recruitment, as well as in the fisheries data of the historical and recreational catches;
This one is brilliant..
· However, if there is a significant level of stochastic variation on top of a presumed deterministic stock-recruitment relationship (one level of stock size gives rise to a range of recruitment levels (then this interpretation is not the only one possible. A high proportion of smaller animals relative to larger ones could also be due to the appearance of numerous strong recruitment years. This confounding is particularly vexing because the possible interpretations are quite divergent – one of high fishing mortality and the other low fishing mortality and strong recruitment.

In order to remove this confounding it would be necessary to incorporate recruitment variation into the estimation process for the stock mode. One way to do this would be to estimate a recruitment ‘anomaly’ for each year of the fishery (for a concise summary of this topic and other approaches see Walters & Martell (2004, p. 96)). Preliminary runs of the model using this estimation approach ended up with very large recruitment anomalies estimated for the years 1993/94. The estimation process clearly preferred the strong recruitment interpretation to the high fishing mortality interpretation. The problem with this estimation is that we only had ‘snapshots’ of composition information (one in 1994/95 and one in 2006/07) to inform the model, not a time series. Time constraints prevented a detailed investigation of this issue; however, the following points are pertinent

Sensitivity to uncertain catch history

· The use of boat registration information and Fish Board records to construct historical changes in harvest has been criticised as a source of model bias. Likewise, there is uncertainty about the accuracy of recreational harvest estimates.

Regards
HOnda.

[caster226]

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[Lovey80]

LoL Caster some of us actually do hunt down and Kill Pink Sea Kittens.... I blame any loss of Biomass on global Warming.

[Lovey80]

Big Deez where did you go?

I read that link to the report on the PPB Snapper. Thanks for the link it was a long but interesting read.

Considering that QLD Anglers that hypothetically would be chasing Snapper larger than 40 or 45 cm, I highly doubt that there would be too much issue with them swallowing small long shank hooks designed for Whiting. Again I highly doubt that we have a need for concern for the survivability of shallow water returned snapper, especially considering most will be targeting them with a 4/0 - 5/0 Circle hook or a Soft plastic jig head.

Do you have an answer to my previous questions?

Cheers

Chris

[PinHead]

do any of you blokes arguing about this even fish for snapper because you come across as not having a clue for the most part. be nice if you could say what qualifies you to say the fisheries is wrong and you are right. seems more like a couple of keyboard heros just stirring the pot on a subject they dont really have any experience about.

and another keyboard hero rides into town..care to enlighten us with your credentials that makes you more entitled to an opinion on snapper stocks moreso than anyone else in Qld. Remember..these stocks are "owned" by all Queenslanders whether they fish or not.
Have you asked the Fisheries scientists if they fish for snapper..if they don't then solves it all doesn't it? Can the lot.

[johnlikes2fish]

Hi Caster I have fished most of my 43 years sometimes for Snapper (kayak and land based) I have a BSci (Env) which encompasses lots of statistical analysis, and 15 years professional experience, I hope this satisfies you.
I dont need to ask what you bring to the table Caster your previous post says it all.

[caster226]

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[PinHead]

40 years pl us of fishing both sides of the country from the beach bay cliffs and wide grounds. over 20 years this side of the big island now. fish with some gun snapper fishermen that a few blokes on here know go prety good that say exactly same thing. smaller fish. less fish and they are deeper for the most part. banks dont produce what they used to tempest doesnt produce what it did and the big catheredral fish are few and far bewteen now. numbers in the bay have crashed only the river fishes better than it used to. ask the pros how their catches are. ask the better charter skippers that have been in the game for more than a few years. the only idiots saying there isnt a problem is guys that cant fish or took up fishing a few years ago and are finally getting some sort of a clue about these fish.

sorry caster..you have only been over here for 20 years..your opinion does not count..you cannot comment without at least 30 years here..sorry.
You don't get it..EVERYONE has a say on this..all Queenslanders..not just those that have degrees or think they have fished with "gun" snapper fishermen..Everyone. and who started all this..some of your charter people!!!

No one is saying there isn't a problem..show us some real evidence first..are your gun fishos experts in environmental science and talking water samples to see if the water quality is the same as years back. Are the so called better charter operators seekign new grounds or have they just flogged the guts out of their favorite areas continually.

I just had a brilliant thought...if the snapper stocks are in so much peril then shut the lot for a year..pros, charter and recs..all out for 12 months...let's hear the GC charter blokes scream about that one...but I am probably just one of your idiots.

[PinHead]

reality is:
1. Quantifying if there is a problem. This has to be done as accurately as possible..and with fish that isn't easy. They live, die and move around. Water quality changes therefore they move to other areas of more favorable conditions. You would be flat out finding any in the Bay at the moment due to the water conditions.

2. Once you have established there is a problem, you then have to set in place measures to solve the problem with an end result being your aim.

3. You have to set in place periodoc checks to see if you are heading to your end aim..no point arriving in 10 years time and finding nothing has changed.

4. You have to have alternative measures in place in case your original solutions are not giving results based on periodic checks.

5. There has to be rewards at the end for those that have hepled achieve the result (if it is met).

[honda900]

Well said pinhead, couldnt agree more on all points..

regards
Honda.

[caster226]

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[Lovey80]

Who are you refering to? Who is trying to derail the process? And what process are you refering to? The one where the gov't makes a political decision to appease the greens and a lengthy, costly consultation process wastes everyones time for a result that is predetermined? Going by the logic of alarmists like you Pinhead should be the one calling for a Snapper collapse based on his Snapper catching ability

I guess it takes a bigger man than you to not blame other for their own short falls.