[Coral-List] Palau`s UN ambassador error on parrotfish
dfenner at blueskynet.as
Sat Sep 25 00:05:04 EDT 2010
This certainly seems to me to be a very confused statement with many
problems. One problem that may not be too obvious, is that if coral reefs
are being used to justify stopping the fishing of sharks on the high seas,
is that sharks in the high seas are not the same sharks as those on coral
reefs, by and large. There are two separate groups of species, those that
are reef sharks, and those that are pelagic sharks. You could
(unfortunately) remove all the pelagic sharks, and there would be little or
no detectable effect on reefs, I would predict. I'm no expert on sharks, if
there is, maybe they should jump in, but I do know a couple sharks that may
cross between these two ecosystems, maybe there are others. Young whale
sharks are seen around some reefs such as those off Ningaloo Reef in Western
Australia. I believe they were found to be eating schools of small fish
hovering over deep ridges out from the reefs. In some places they eat coral
spawn after mass coral spawning I believe. But they also swim vast
distances across open oceans from one place to another, and less is known
about where the adults are than the juveniles. But I wouldn't call them a
reef fish. Tiger sharks pray on large items such as turtles, seabirds and
seals, I believe (which is probably why they are responsible for some
attacks on humans). There food items tend to be coastal at some times of
the year, and they may move between food sources, they certainly swim
between islands and can cross very wide open ocean gaps (Like Hawaii to the
Americas). So although found around shores at times, I wouldn't call them
specifically coral reef sharks. Both of these sharks have some interactions
with reefs, eating coral spawn, eating turtles that may spend time on reefs,
seabirds and monk seals that feed on reefs or below reefs.
But typical reef sharks are things like grey reef sharks, blacktip reef
sharks, whitetip reef sharks, reef shark (Atlantic), nurse sharks, and
several more species that are less common. They all are integral parts of
coral reef ecosystems. The Palau ambassador is correct that they are
referred to as top predators.
More broadly, of course they are right that there are reports of sharks
being much depleted on the high seas. That may not be everywhere, it may be
much more some places than others, that's out of my field. There is heavy
pressure on all sharks for sharkfin for sharkfin soup in Chinese culture.
The possession of shark fins is illegal in the states. Here in American
Samoa, an entire container load of them was found on a tuna boat in the
harbor, in US waters, and the parties were prosecuted.
Sharks are also depleted on most reefs around the world where there are
people, with some exceptions. They grow slow, mature late, have only a few
pups, and their ability to recover from fishing is very low. FishBase
(www.fishbase.org) reports an index of vulnerability to fishing for most
every fish species, so you can easily look up shark species and see how
vulnerable they are to fishing on a 0-100 scale. Most reef sharks score
high, in the 75-100 range, while some common small reef fish score around
15-35. The index is based on published articles in peer-reviewed journals,
Cheung et al. 2007 reviews it and is an open-access article.
I would argue that the trophic cascade effects of removing top
preditors such as sharks are masked by the fact that fishing also removes
smaller fish. In a very specific fishery such as that for Coral Cod on the
Great Barrier Reef, where that is the only fish being caught, the trophic
cascade effects have been demonstrated.
A new article on reef sharks in the Caribbean is entitled "
I congratulate the Palau government on their efforts to protect sharks
in need of protection. They are on the right track. But getting the
science all confused may open them up to criticism that their case isn't
based on strong science. The fact that this person's statement is badly
mixed up doesn't mean that their policies aren't based on good science, I
hope they are though I don't know (I don't know the status of reef sharks or
pelagic sharks in that area).
Cheung, W. W. L., Watson, R., Morato, T., Pitcher, T. J., and D. Pauly.
2007. Intrinsic vulnerability in the global fish catch. Marine Ecology
Progress Series 333: 1-12. (an open access article)
----- Original Message -----
From: "Steve Box" <steve at utilaecology.org>
To: <coral-list at coral.aoml.noaa.gov>
Cc: "Steve Box" <steve at utilaecology.org>
Sent: Thursday, September 23, 2010 10:28 AM
Subject: [Coral-List] Palau`s UN ambassador error on parrotfish
>I thought I would bring the list serves attention to a statement yesterday
> by Palau's UN ambassador Stuart Beck when talking about the countries call
> at the general assembly for international action to address shark fishing
> the high seas:
> "In Palau, the reefs depend on the predators - and sharks are the top
> predators - because if you take them out, what proliferates will kill the
> reef, parrotfish for example," he said. I found this quote on a BBC
> covering the UNGA and assume it has been widely repeated in the media.
> It is a dire shame when officials who are proponents of international
> conservation action (and thus one would assume to be better briefed on the
> relevant science than most) can make such erroneous statements, which are
> then compounded and disseminated by wide spread media coverage.
> So whilst the coral list has been preoccupied of late with seemingly
> tangential discussions on media spin, climate change, oil spills and more
> media spin, simple facts such as parrotfish being essential to reef
> and fundamental to coral reef ecology are being badly misrepresented.
> Stephen Box PhD
> Executive Director
> Utila Centre for Marine Ecology,
> Bay Islands, Honduras
> Coral-List mailing list
> Coral-List at coral.aoml.noaa.gov
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