[Coral-List] The Chagos MPA - what went wrong?
douglasfennertassi at gmail.com
Mon Sep 29 07:16:58 EDT 2014
So your criticism of the Koleway paper is "really??" Could you be a
tad more specific?
Sorry about my statement about citations in the "Lazy Fish" article, I
should have said "links." There is a link to info on setting up the NW
Hawaiian Is. MPA, but no link to the "lazy fish" research, apparently
because it hasn't been published yet. There is discussion of an article by
Lehodey, I was able to easily find it on Google Scholar,
Modelling the impact of *climate change *on Pacific *skipjack tuna *population
and fisheries <http://link.springer.com/article/10.1007/s10584-012-0595-1>
B Calmettes, J Hampton, S Nicol - *Climatic change*, 2013 - Springer
Abstract IPCC-type *climate *models have produced simulations of the
oceanic environment that can be used to drive models of upper trophic
levels to explore the impact of *climate **change *on marine resources. We
use the Spatial Ecosystem And Population Dynamics *...*
The title has a link to the article.
I look forward to the publication of the research on selection for reduced
tuna movement, just as I look forward to reading your publication in
Advances in Marine Biology when it comes out, as I'm sure others do as
well. Also the chapter on the toothfish and MPA in South Georgia.
I don't remember writing in my post that the Koldeway et al. article is
"gilt edged proof" of anything. I provided some references in my post for
people to read some other viewpoints that might provide some balance to
what I considered a very one-sided posting (particularly the New Scientist
article). By providing the reference and link, readers can read it and
make up their own mind.
Yes, movement of tuna has surely been selected over long periods. It
is not necessary for the tuna to stop all movement in order to be protected
by the MPA. If you care to take a look at the article I pointed to
"Protecting the Chagos Archipelago" you will find a map, Figure 6, which
shows that yellowfin tuna, on the average, travel less than the diameter of
the Chagos MPA, and skipjack travel only slightly more on the average. A
similar figure is presented in the Sheppard et al 2012 paper, as Figure
10. That suggests that even without selection for "lazy fish", the MPA can
provide at least some level of protection for those two species of tuna.
With reduced movement, it can protect even more, and such selection will
surely occur, though how much evolution will occur in response remains to
be seen. A slight reduction in movement may well produce a slight
reduction in fitness, but open tuna fishing will reduce populations a lot
more. Also, Sheppard et al. (2012) write, "Migratory predators like tuna
do not move randomly, but associate with certain environmental and/or
physical features (Hughes et al., 2010; Schaefer and Fuller, 2010), meaning
that positive, measurable reserve effects on pelagic populations exist
(Hyrenbach et al., 2002; Roberts and Sargant, 2002; Baum et al., 2003; Worm
et al., 2003, 2005; Jensen et al., 2010). Several studies have shown
species can benefit from no-take marine reserves (Polunin and Roberts,
1993; Palumbi, 2004; Beare et al., 2010; Jensen et al., 2010). Pelagic
MPAs are an important tool in marine conservation management (Game et al.,
I don't recall anyone ever saying that MPAs provide 100% complete
protection for any species of fish that moves. In fact, the "spillover
effect" of MPAs, is a benefit that requires the fish to move and for some
fish to move out of the MPA and get caught. Spillover is a potential
benefit to tuna for the Chagos MPA, just as it is for small coral reef
MPAs. In fact, if you make an MPA too large, you diminish the chance for
spillover since more fish are too far from the edge to swim out. MPAs can
be thought of as "natural fish farms" where fish are protected enough to
grow larger and more abundant, then some fish spill over the boundary and
get caught. There is some evidence that MPAs can actually provide
increases in fish catch for fishermen, though they surely don't always do
so. That would be in addition to the conservation benefits of making sure
that fishing doesn't drive fish species to commercial or local extinction,
ending benefits to humans and damaging the ecosystem. Many coral-listers
will be familiar with many of these things.
"the fishers have a vested interest in maintaining healthy stocks"
Really??? Fishers have a vested interest in making more money, and they
do that by catching more fish. Yes, there is an incentive for fishers for
long term maintenance of the resource. But it is overwhelmed by the much
stronger incentive to be the first to catch the fish (instead of getting
nothing) and the incentive to have the rewards now instead of later. Tuna
is big business, a single purse seiner can hold about 1000 tons of tuna, at
$2 a pound, that's $4 million worth of tuna in one boatload. That is
industrial fishing. In the Pacific, tuna is a $2 billion a year business,
that's not exactly chump change. The history of fishing and attempts to
regulate it are littered with examples of fishers responding to the
incentives of scramble competition, also called "tragedy of the commons" in
which the "early bird gets the worm" and "he who hesitates is lost."
Hilborn calls the examples often quoted of fisheries failures as "the
litany." The poster child is the Canadian cod industry, overfished for
centuries (as documented in the little popular book, "Cod"), it finally
collapsed, and Canada lost a billion dollar industry and the stocks haven't
recovered decades later. The primary reason for the need for regulation is
that the economics of fishing are such that if unregulated, fishers have an
incentive to fish the stocks to oblivion, also known as economic
extinction, where net profits are zero. It is the regulators, not the
fishers, who may, may, be able to respond to the long term incentive, to
regulate the fishery for the long term maximum benefit of all. They do so
with the determined opposition of fishers, whose strongest incentive is to
catch all they can, as fast as they can. In this case, the incentives are
in the millions to billions of dollars, so irresistible. So the reality is
that the stocks of some tuna species are not overfished, others somewhat
overfished, others are grossly overfished like the bigeye that the "lazy
tuna" article points out is at just 16% of the unfished biomass, and others
like some species of bluefin tuna are approaching economic extinction
(which benefits no one). Yet fishers continue to pursue them
relentlessly. According to Wikipedia, in 2008 the price of bluefin in the
Tokyo fish market was $23 a pound, and several individual fish have gone
for $150,000 or more. "In 2013, a 222-kilogram tuna was sold at Tsukiji
(the Tokyo fish market) for $1.8 million, or about $8,000 per kilogram."
Not all species of fish around the world are overfished, but more and
more species are fully fished, and many are overfished and others are
"recovering." It is a continual battle to manage them, and Kolloway et al.
write that "the western Indian Ocean remains a region with some of the most
exploited poorly understood and badly enforced and managed coastal and
pelagic fisheries in the world." "While within the commercial fishing
industry the Chagos/BIOT fishery is considered well managed when compared
to other fisheries in the western Indian Ocean, this needs to be taken in
the context of the generally poor or non-existent management within the
region and the weak RFMO described earlier." When the stocks are not well
regulated, some people say MPAs may be the only tool left that works.
(because the tuna move around, the tuna within the Chagos MPA is not a
stock, it is part of the entire Indian Ocean stock.) That is the reason
that MPAs are used for fisheries management on coral reefs, not because
they are a panacea, but because "conventional" management is a total
failure. Of course, the primary reason for MPAs on coral reefs is
conservation, the fisheries benefits of "spillover" are an additional
benefit for local fishermen. Koleway et al. write, "bycatch is a serious
conservation issue that is complex and ecosystem-wide in its effects, and
the bycatch from tuna fisheries in Chagos/BIOT is significant, particularly
for sharks." So there are conservation issues with tuna fishing.
On Sun, Sep 28, 2014 at 7:42 AM, Magnus Johnson <m.johnson at hull.ac.uk>
> Oh my.
> You're citing the Koldeway paper as gilt edged proof that a no take marine
> reserve will benefit the Chagos??? Really??
> I looked with interest at the link you provided Douglas but don't see any
> citations? Am I missing something?
> I also think the idea of promoting MPAs because they will encourage the
> evolution of changes in fish behaviour that have been previously driven by
> non-anthropogenic factors for hundreds of thousands of years woolly
> headed. Much, much better to have sensible and well managed pelagic
> fisheries where the fishers have a vested interest in maintaining healthy
> stocks and the funds generated by licence fees will support meaningful
> enforcement/management. Otherwise you'll get no enforcement and lots of
> IUU fishing.
> Lazy fish are not a good thing to wish for, in the same way as small fish
> caused by overfishing (not something that occurred in the Chagos pelagic
> area when it was fished and managed) are not a good thing. They move
> around for a reason, because they have to - migration is expensive, not
> something done on a whim. I really find it quite unbelievable that this is
> being promoted as a potential strategy or benefit. Bonkers. Completely
> flippin' bonkers.
> If you want a good example of a well managed fishery and MPA working
> together I suggest looking at the South Georgia toothfish fishery (a
> chapter on this in the Advances volume too).
> And if you want a really significant issue to worry about, I'd start with
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