They protect biodiversity by protecting the target species. It's not hijacking, it's how they work. They are a fisheries management tool. The manage fishing. Biodiversity protection is secondary and results from this.

The strip method you described would not give easier compliance because two different navigation methods tend to be used for near and off shore. Close to shore, most fishermen navigate by landmarks and many don't even have GPS. So being able to identify the boundary from landmarks is more important. Offshore it makes more sense to use simple shapes like rectangles aligned with the grid. Close to shore a 3nm may be too big which may reduce spillover. Far offshore a 3nm wide zone may become meaningless, especially if pelagics are the primary targetted species.

They are not designed to protect individual species.

That does not mean that they are not a fisheries management tool.

When was the last time you saw a sanctuary zone implemented by fisheries?

I prefer not to let bureaucratic allotment of authority to dictate my view of reality. Marine parks control fishing effort. Therefor they are a fisheries management tool. Any conservation benefit occurs because of the management of fishing effort.

Rubbish- land marks can still be used and with greater ease and accuracy than triangulation methods.

Who said anything about triangulation?

Please explain???

The larger the marine park, the closer you get to a 'virgin' ecosystem in the centre. The smaller the marine park, the stronger the spillover effect - provided it still gives some real protection. The more mobile the target species, the larger they should be. This does not mean that you design the marine parks for a single species, just that you should try to take the most important species (froma  fisheries management perspective) into account.

Then your view of reality will always be skewed

The whole 'conservation tool' thing is just the path of least resistance. It's not the reason for marine parks, just the reason given to the people who oppose them.

Do you understand the concept of navigation from landmarks?

Sure, but you don't use triangulation when you're out fishing in a boat.

A larger NTZ would in effect cause stronger spillover, albeit it would take a longer time to spool up so to speak...

On a per unit area basis, smaller marine parks will give a stronger spillover effect.

So you agree then with detractors that the reasons given for the introduction of them are nothing but a lie, yet because you agree with the underlying stealth then the lie is justified...how interesting

Yes and no. I don't think the lie is justified. I think we are getting poorly designed marine parks as a result of that lie. It is also not necessarily a lie. Marine parks do protect biodiversity. It's just that they do this by managing fishing effort. Saying that they protect biodiversity instead of saying they managing fishing effort is not a lie. It isn't even an omission, because it is obvious how they work. Or at least, it should be. Many people probably do promote marine parks with only conservation in mind. To them, the fact that it is a fisheries management tool and the subtleties of the two different approaches don't really matter. A bureaucrat has a choice between saying 'conservation' and 'management' and will simply say whatever keeps him in a job. The only people I really blame are the fishermen who refuse to see them as fisheries management tools and who refuse to interact with fisheries managers in a way that gets the best outcome for fishermen, rather than an outcome that achieves the same level of conservation but causes unnecessary difficulty for fishermen. I blame the boat fishermen who want only to maintain their lead in the 'arms race' without considering what is best for the fishing community as a whole. 

You obviously have never fished or navigated from a boat.

OK then, please enlighten us how you use triangulation from a boat.

No they won't

Yes they will. They have a higher ratio of circumference to area. To demonstrate, let's take this to the extreme. Imagine that the 20% was a single circular block somewhere on earth covering 20% of the water. There would be plenty of fish in it, and plenty of fish on the boundary. However, that bounty at the boundary would not make up for that vast area of not take zone. The net spillover would be negative. If you broke it into two 10% blocks, fishermen would be much better off. If you kept breaking it down further, you would eventually get positive spillover. As you approach the other extreme, you would get maximum spillover, but little biodiversity increase.

As you go to the the other extreme there are two main issues stopping you from going too small. One is practical enforcement issues. The other is that for small NTZ's, the boundary effects reduce the 'effective area of protection'. This includes things like the natural movement of fish over small time periods, their tendency to follow a burly trail out of the NTZ, casting into the NTZ etc. If the 'effective area' is zero then you really are just transferring effort. Some of the NTZ proposals for small rivers with shore fishing zones on both sides (I'm not sure if there are any like this in the proposals I have put up) would be more about trasnferring effort than spillover, however there would still be some buildup of fish that are protected by various structures that make them difficult to get at from the shore.

Do marine parks really protect biodiversity? A lot of marine species aren't even fished for. They do nothing about the bigger threat of pollution and degradation which attacts the ecosystem at its very base. Most fished species are migrant, so a marine reserve doesn't really protect these. Isn't biodiversity about sustainable populations of all species? Therefore this doesn't require that these have to be pristine or unexploited. Marine parks don't do any favours for areas outside the park with their tendency to displace fishing effort.

Yes they are.

No they are not, at least not in any capacity except tokenism

It's about improving the lot of fishermen.

It's about displacement of effort

They don't teach triangulation. They may teach something else.

And again, I contend you have no idea regarding marine navigation. If you use the bearings of any two fixed landmarks to navigate, that is triangulation

No they are not, at least not in any capacity except tokenism

What are you responding to IQ? I did a word search for the italicised text and didn't find it on this page.

Why do you think you speak for the angling community when you haven't even picked up a rod in the past 10 years, FD?

That's not what I said pj. Read it again.

You distinction between boat and land based anglers is a totally arbitrary one which makes no sense at all.

I don't make any distinction. They are often the same people. Reducing the need to purchase or use a boat to catch a feed does make sense.

Its highly unlikely that banning the former will benifit the latter.

Who said anything about a ban?