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Fishing Havens and Marine Parks


W4z

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I don't know if he is that educated on the subject. He seems proud of involvement in the zoning of the Bateman's Bay Marine Park. But his so called evdence is very anecdotal and opinion based. He blamed the initial drop in fishing

tourism in the area on scaremongering by anti marine park groups yet research has shown a very steep decline in recreational fishing in the Jervis Bay Marine Park 10 years after it had been established (long after any so called

scare campaign would have worn off). He plays up the fact that there were some commercial buy outs/ exclusions but actual scientific research has on shown modest improvements in fish numbers in green zones compared to

fished zones in the Park. You are bound to get some positive effect but as these green zones are lost to fisherman and fishing pressure tends to be displaced by them and there is not likely to be an improvement in the fishery or an

overall increase in the biomass. This has been shown many times when marine parks are introduced in areas where there is already effective fisheries mangement. In fact in one of the offshore zones opened to rec fishing a

decline was seen compared to an area where commercial fishing was allowed!

He also refers to coral trout studies on the GBR, but again when you look past the unrestrained postive spin there is no evidence that green zones have improved the fishery/ increased the biomass.

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Thanks for the input billfisher.

Having only really been fishing for the past few years I have very limited knowledge on the subject and my opinions have been formed so far based on reading other people's opinions online.

I've started to want to read or hear some unbiased information on the subject but don't know where to find it. When I read this article by Rob it put a totally different spin on it for me and that's what made it interesting. It makes me wonder why an ambassador for the sport who apparently loves recreational fishing would be pro what some many others are against unless he has good reason. There is always the chance of political reasons, as he himself suggested in his article.

Anyway, I'd love to read anything you have on the subject like official reports or studies.

Thanks again

Waz

Edit - Sorry mods for posting in the wrong section

Edited by W4z
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http://www.cell.com/current-biology/abstract/S0960-9822(12)00395-8?cc=y#

Larval Export from Marine Reserves and the Recruitment Benefit for Fish and Fisheries

Have a look at this one. It was even featured on ABC's Catalysts show where the presenter gushingly repeated

the paper's claims about fishery and stakeholder benefits from the GBR zoning. The lead scientist was very young looking! If you look under the comments bar you will find that Prof Colin Buxton totally picked it apart, showing that they haven't proved that the overall fish biomass has been increased (nor was this likely). The authors then seemed to back away from their previously claims.

Edited by billfisher
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Interesting information and I am sure Hilborn knows his stuff.

My position is that I don't want any introduction of Marine Parks that restrict where I can fish as I would rather see better policing of recreational fishing laws, bag limits and pollution. However I would rather err in the favour of conserving fish stocks rather than depleting them because the historical examples of decline through inaction, neglect, deception or greed are overwhelming.

Looking at the links Hilborn is certainly not saying that Marine Parks ARE a waste of time he is actually saying they CAN be a waste of time.

In his own words...

RH: You certainly almost always, if the area has been fished, get an increase in fish stocks inside the reserve. What really makes a difference is if the whole area has been subject to overfishing, then marine parks actually have benefit. If the area is not overfished, then they dont generate more fish overall.

He seems to be saying that the most important factor is whether areas are already overfished. I guess this means we have to look at whether Sydney Harbour for example is overfished or not. Goodness knows how that judgment is established but certainly from my perspective fish stocks have improved over the last 5 to 10 years from a constantly declining base prior to that. This is of course anecdotal evidence but I can assure you that proven science often agrees with anecdotal evidence.

It is important to note here that Hilborn's well-constructed arguments are often expressed more globally so applying a local interpretation to this may not be appropriate.

As an example he mentions that restricting commercial fishing in Australia may put more pressure on fish stocks in Asia as they try and keep up with a demand through their local fisheries. I can see that this additional pressure could have adverse impact on fish populations in Asia. A collapse in these fish stocks could result in a demand coming back to the Australian or other fisheries in 5 or 10 years time creating a bigger problem than before.

Hilborne effectively proposes that spreading the load through sustainable fishing in all suitable fisheries is a better strategy and he may well be right. It certainly makes sense to me.

However, whether you can apply this global principle to a local non commercial fishery such as Sydney Harbour is another matter.

There are many factors here and again the science is frequently incomplete, distorted or misinterpreted. A typical example of this is the North Harbour Marine Park and the reduction in access to Southern Calamari fishing for recreation anglers. One prominent fishing writer suggested that this closure excluded 40% of the harbour from Calamari fishing.

If you take your measurement from the SH bridge and exclude middle harbour entirely and use the total area of the water encompassed by the marine park then you can get close to this 40% figure. However, if you use the shoreline (which is the actual habitat for the squid) and include middle harbour up to Spit bridge then the area lost to calamari fishing in Sydney Harbour marine parks is around 3%. 3% may be too much. I don't know but certainly this is a distortion in the facts which is prevalent in these kinds of emotive debates. My point here is there are lots of “fact”: out there which sound convincing but do not stand up to scrutiny.

Billfisher’s references are very convincing and I appreciate the content he has provided as it has helped my understand the opposing arguments.

At the moment I am on board with Hilbourne but I interpret his findings a little differently.

Cheers

Jim

Edited by fragmeister
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A decline is not the same as 'overfished' Jim. Maximum sustainable yeild is usually regarded when a stock is fished down to 30 - 40% of the unfished spawing biomass. I think Hilborn would

be using this definition (ie overfishing would be taking more than the maximum sustainable yeild).

Anyway glad you found the articles interesting. Here's another one which looks at things from a conservation perspective and concludes that large marine reserves such as those on the

GBR are not the best solution:

How ecosystems can keep their fish, and we can eat them too.

http://theconversation.com/how-ecosystems-can-keep-their-fish-and-we-can-eat-them-too-29977

Edited by billfisher
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Thanks Billfisher,

I get your point about overfishing and declining being different as the terms are used in fish stock management.

I was mainly considering Sydney Harbour and certainly the main cause of fish population reductions was commercial over over fishing.

Is it being overfished now? Not sure about that one but I certainly believe it has improved in the last 5 -10 years without its being made a marine park.

I think Sydney Harbour is a particularly fruitful marine environment that has an enormous potential for bouncing back.

Its probably a less critical area than some of the other estuaries up the NSW coast but of course it gets a lot more focus being what it is.

To me the greatest disappointment is not so much the fish stocks but the contamination levels. I fish the harbour every week ( just about) and it breaks my heart to know that pristine looking water

has contaminant levels that has lead to bream intake recommendations of 150 grams per month... not even a single decent feed. Whether you believe it or not it is still a sad state of affairs.

So far every thing I read takes me back to where I started - better policing of recreational fishing laws, bag limits and pollution.

Thanks again for the article links

Cheers

Jim

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