Tuesday, April 17, 2007

The Palau no-take model and global warming

No-Fishing Zones in Tropics Yield Fast Payoffs for Reefs by Christopher Pala in the New York Times neatly summarises some of the lessons learned in Palau and elsewhere about how to manage fish stocks more sustainably, and reports ambitions to replicate the approach in some Caribbean countries and Indonesia.

Noah Idechong of the Palau Conservation Society has successfully pressed for the extension of reef protection to areas in Palau that "best resist bleaching, or recover fastest from it". His achievements, including this one, are remarkable, and he has been widely hailed for them (see, for example here and here).

It has been claimed, at ITMEMS and elsewhere, that an approach to management that takes special account of reefs that resist and recover from bleaching offers the best practicable strategy in many circumstances in the face of rising sea temperatures (assuming, of course, that other human pressures are brought under control). 'Reslience' has become a buzzword in tropical marine conservation management.

As noted here, the IPCC WGII summary includes language that allows for the possibility of thermal adaptation or acclimatisation by corals to temperature rises of up to 3°C during the 21st century. But I have yet to encounter a scientist who thinks corals really could adapt to such rapid change (see, for example The canary and the parrot).

[P.S. 6pm 17 April: I have now talked to a scientist who says that one should not rule out the possibility that corals have the capacity to adapt this fast; but he is careful about going on the record, seeking to minimise the chances of being quoted out of context]


Anonymous Tom Goreau said...

Dear Caspar,

The "resilience" claim is bogus wishful thinking and/or self delusion, and is an outgrowth of people telling the funders what they want to hear, which is that coral reefs can bounce back from any disturbance so we need not reduce stresses, and by simply waiting and doing nothing they will bloom forth all by themselves despite increasing global warming, pollution, and disease.

If you look at all these spots that people are calling "resilient" reefs, claiming that they are more resistant to stress, they are either 1) areas of high chronic stress like muddy inshore areas with poor circulation in which only stress tolerant strains have been able to survive, but which have low genetic diversity, or 2) areas that far less temperature stress due to specific local differences in water circulation, mainly areas of localized upwelling and cool water. Both types of situations 1) and 2) are features that Ray Hayes and I identified very early on in the first bleaching episodes, but naturally those touting "resilience" claim to have discovered.

In most cases of type 2 these are not more resilient at all, they were simply less stressed to begin with. These are the kinds of places that they are trying to include in Palau, but they have plenty of type 1 sites in the lagoon, especially now that the road building and land clearance are giving the lagoon a mud bath. When I filmed in Palau in 1997 the reefs were overwhelmingly Acropora, after the bleaching they were overwhelmingly Porites because they were the main survivors. Curiously, there is no interest in reef restoration at all on the part of the coral reef research and mariculture institutions in Palau, only on the part of the fishermen who are suffering the consequences of habitat deterioration.

Best wishes,

Thomas J. Goreau, PhD
President, Global Coral Reef Alliance

4:52 pm  
Anonymous Charles Sheppard said...

We have long known that protected areas are crucial to the survival of many kinds of species. But the gap between those who know and those who don't, is still far too big. Not only in the tropics, where the NYT story comes from - is close to home as well. Just a couple of weeks ago, there was a blockage of Irish ports, disrupting ferries and other vessels, by fishermen protesting against protected area closures. People doing that really do have their heads in the sublittoral sand. Will a protest make the scallops, demersal fish and the rest breed more?! And why dont they want protected areas when all the evidence shows they will benefit after a very few years? Is it education? Is it plain immediate selfishness?

Here is an extract from Marine climate change and conservation priorities, a guest editorial I just wrote for Oryx (41):

'...Local issues are more manageable in principle [than global changes such as ocean acidification], and these include sewage outfalls, industrial and agricultural pollution, dredging, and landfill operations causing sedmination, which all stress or destroy productive marine habitat. It is already being stated by some marine park managers that there is little point in trying to control these any more because the global issues will overwhelm their system anyway. But, in terms of a decade or two, this is not usualy true. In many cases a habitat collapses, or its keystone species die, because of a combination of stresses. Sewage may harm but not kill something if the temperature remains amenable, and a temperature rise may not kill a habitat if pollution pressure is low. In other words, it is a combination of events that causes many fatalities -- death by a thousand cuts. That has been the history of many marine systems to date. If managers continue to tackle local, addressable issues, then they can put back the lethal effect of temperature by perhaps a decade or two, and who is to know how humans might respond during the intervening time? We are an ingenious species, if nothing else...'

Charles Sheppard
University of Warwick
Editor: Marine Pollution Bulletin

5:09 pm  

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