freediver wrote on Oct 24^th, 2008 at 6:16pm:


It's has quite a bit to do with it. I don't have a copy of Hilborn's paper, but in refering to it he mentioned needing a generation to pass in order to assess a reserve effect. As a player in fisheries management why don't you get hold of his paper and put up your review?

freediver wrote on Oct 24^th, 2008 at 6:34pm:


How do you know there is an error then? I thought the quotes from Burdens of Proof dealt rather well with your simplistic notions. I notice you haven't made any comments about them.

You not debating at all FD. Your several pages of obtuse, sophist comments don't do you or your policies any credit.

I'm not debating because you are not putting forward a coherent argument. You make a clearly illogical claim, attribute it to scientists, then try to back it up with a quote that has nothing to do with your original claim. If you think someone actually said it, quote them, but don't expect anyone else to trawl through everything they've ever said just in case they stumble across it.

Or, just concede that you misinterpretted what they actually did say.

I'm not debating because you are not putting forward a coherent argument. You make a clearly illogical claim, attribute it to scientists, then try to back it up with a quote that has nothing to do with your original claim. If you think someone actually said it, quote them, but don't expect anyone else to trawl through everything they've ever said just in case they stumble across it.

So doesn't the phrase lack of temporal replication mean anything to you. 

Or, just concede that you misinterpretted what they actually did say

Well interpret this then (from Ray Hiborn):

A paper in Science (Roberts et al. 2001)
purported to show an example of how a
marine protected area (MPA) increased
yields outside the protected area, when in
fact the abundance of fish outside the protected
area increased within one year of the
establishment of the MPA. Any competent
peer reviewer would have seen the flaw in
this logic—the theory of MPA impacts on
adjoining areas requires at least a generation
for abundance to build inside reserves
and recruitment to spill out (Hilborn
2002). The displacement of fishing effort
from inside to outside the reserve should
initially cause abundance outside to
decrease, so the increasing abundance outside
the reserve after MPA establishment
must have been due to an uncontrolled
effect.

tallowood wrote on Oct 25^th, 2008 at 7:59am:


I though Burden of Proof put paid to that notion. Ray Hilborn probably had similar justifications. I could get a copy of his paper but why should I bother if you and FD just ignore it or call him names?

"However, it is imprudent to make untested assertions about the primary consequences of reserve protection on fish population dynamics, and then to extrapolate those effects to fishery-level predictions. Typical predictions of fishery enhancement could be invalidated for a number of reasons, including displaced fishing effort around the reserve boundary (Parrish 1999), recruitment limitation (Doherty & Fowler 1994), self-recruitment rather than larval export (Leis 2002), irreversible changes in species assemblages, and any number of unknown causes due to the underlying complexity of the ecosystem. Without empirical substantiation, predictions of fishery enhancement are deductions based on circumstantial evidence and ancillary information. Furthermore, even if model assumptions are logically correct, it is not sufficient to test only for the existence of reserve effects. Of real relevance is the magnitude of an effect and the certainty (or lack thereof ) that surrounds estimates of it".

Thanks for finding the quote PJ. It does look a bit mroe familiar now. I've probably responded to it here already. While there are key differences between his statement and your paraphrase of it, Ray's comments are still wrong.

Not really any difference. My papraphrasing was a bit brief, but I thought you would have remembered the original quote.

Obviously it does not require a generation for either abundance or relative abundance to build up, as my brief example on the previous page demonstrates.

You 'example' is not an example but a theory you thought up and doesn't demonstrate anything. As burdens of proof pointed out there are several processes that could invalidate it in the real world. As well as their point that merely showing an increase in fish numbers inside a reserve does not prove a fishery-wide benifit. Also there is point that the magnitude of the effect and the certainty that surrounds it that is of the most importance.

Nor does it require a generation for spillover to occur. As soon as there is relative abundance there will be some forms of spillover kicking into action. The way he phrases it - "recruitment to spill out" - does not seem to make much sense. Obviously fish will spill out, or recruitment will occur. Perhaps he was trying to refer to a specific mechanism of spillover and was a bit loose with his words. Perhaps he should have just added a few qualifiers such as 'significant', but I suspect that would have ruined the strong, absolutist type political message he was trying to convey.

Pot kettle black. What is 'absolutist' about asking for rigor and empirical evidence rather than theories and mantras.

But the bottom line is, he accused his college of illogic when it was obviously he who erred in logic.

its not obvious at all. Why do you first get a copy of his paper rather than dismissing it out of hand.

Your 'example' is not an example but a theory you thought up and doesn't demonstrate anything.

Do you reject the claim that a no take zone will immediately reduce catch of resident species from within the zone, resulting in an immediate impact on fish numbers compared to what would have happened if the NTZ were not there?

Thats an intuatively appealing theory - but thats all. And I have put up the reasons why it can be invalidated but you have studiously ignored them, which is a form of censorship by the way.   

As Ray pointed out, it is a matter of logic, not evidence. His logic is wrong.

What an admission! I would prefer evidence based policies myself (which is what Ray and Burdens of Proof were on about).   

As burdens of proof pointed out there are several processes that could invalidate it in the real world.

Perhaps you should explain how.

Whats wrong with the Burdens of Proof explanations?

As well as their point that merely showing an increase in fish numbers inside a reserve does not prove a fishery-wide benifit.

But that's not what this particular point is about, is it?

If the point is that marine parks are the ideal (or even needed) fisheries management tool then it is very relevant.

Also there is point that the magnitude of the effect and the certainty that surrounds it that is of the most importance.

That is also not what this particular point is about. Ray made a claim of logic. His logic is wrong.

As above.

What is 'absolutist' about asking for rigor and empirical evidence rather than theories and mantras.

That is not what my comment was in response to. It was in response to his lack of qualifiers in his claim of logic.

Why do you first get a copy of his paper rather than dismissing it out of hand.

Logical errors don't become logical just because you waffle on for a while.

And oversimplification is a standard propaganda tool. Or do you think you have reached the same state of enlightenment as the Greens; of 'just knowing' everything.