[Coral-List] Long term change in Eritrean reefs: past, present, future

Gert Jan Gast gj at fishion.eu
Tue Apr 22 04:04:04 EDT 2008


Dear Tom and list,

Two years ago I was fortunate to organize an expedition for the African
Parks Foundation to Sanganeb Atoll and Dungonab Bay Marine Parks
(http://www.africanparks-conservation.com/apffoundation/index.php and click
the 2 yellow dots in Sudan) with about 20 experienced divers who had been
many places around the globe. The general observation was that, yes,
compared to most other reefs there are relatively many sharks in Sudan
waters at many sites. Mostly reef sharks, but also hammerheads. Manta's and
whale sharks come in autumn to reproduce. But there really is no comparison
to what you describe from the 1960s. 

Main issue is the usual suspect: illegal shark fin trade. In summer the dive
tourist boats do not operate as it is too hot. Without the control foreign
fishing boats (from Yemen?) stay at open sea and little boats come into the
reefs. Of course little catch is needed to reduce populations of long lived
species.

I am not enough of a shark ecologist to definitely say, but I suspect
another cause could be the lack of medium sized fish. We mainly observed
small reef fish or big stuff like hammerhead, manta, dolphins. Emperors,
snappers, etc were conspicuously absent. This of course also due to
continuing overfishing by local and foreign vessels. 

However, we only visited a very small part of the 750 km of Sudan coast.
Anecdotal stories by dive operators tell about "lots of sharks" especially
at reefs between Port Sudan and Eritrea which have been very little visited
and studied. Maybe there are still pockets that look like things were in the
past. Maybe we will be able to discover when civil unrest settles down.
Hopefully researchers find them before the fishers for fin trade.

Best wishes, GJ

--
Dr Gert Jan Gast
Fishion Consultancy
Trawlerkade 32B, 1976CB IJmuiden, The Netherlands
Phone +31 6 5424 0126 Fax +31 255 521546
Email: gj at fishion.eu


-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Thomas Goreau
Sent: 20 April 2008 23:45
To: coral-list coral-list
Cc: Pete Raines; Gordon Sato; Marco Pedulli
Subject: Re: [Coral-List] Long term change in Eritrean reefs: past, present,
future

When my brother Peter was the dive master on the Cambridge University  
Sudan Expedition in the late 1960s they would routinely see 40-50  
sharks on a dive, and they were so thick that you sometimes had to  
push them out of the way to go down (VERY carefully, because their  
skin is like sandpaper and the last thing you wanted to do was start  
bleeding). I wonder how they are now? Those numbers make the  
"pristine" NW Hawaiian Islands seem like at least two thirds of the  
sharks are already gone!

Marco, where are you now? We lost contact a long time ago.

Thomas J. Goreau, PhD
President
Global Coral Reef Alliance
37 Pleasant Street, Cambridge MA 02139
617-864-4226
goreau at bestweb.net
http://www.globalcoral.org

On Apr 20, 2008, at 5:28 PM, Douglas Fenner wrote:

> How are the big fish populations in Eritrea?  The recent reports  
> are that pristine reefs have amazingly high abundances of big fish,  
> primarily sharks (and giant trevallies at high latitudes in the NW  
> Hawaiian Is.).  On the order of an average of 15 sharks a dive, and  
> 7 terminal phase humphead wrasse and 2 bumphead parrots (in large  
> schools so none on most dives but the occassional school of 30, 50,  
> 100 or even 700).  Wildly above levels on almost all reefs near  
> people.  If they are gone, then it could be like Gregor Hodgson's  
> comment about a reef in the Philippines he was able to save from  
> logging sediement- it is like a city with no people- corals look  
> good, but where's the fish?  Over half the biomass on these  
> pristine reefs in apex predators, most scientists today have never  
> seen that.  That's what I'd call pristine, but if it is like most  
> reefs around people, the entire top of the food web is simply  
> missing, a huge chunk gone.  If half the corals were suddenly dead,  
> we'd all be screaming, but over half the original fish community is  
> gone, and most of us didn't even realize it.
> -Doug
> ----- Original Message ----- From: "Marco Pedulli"  
> <marco_pedulli at hotmail.com>
> To: <coral-list at coral.aoml.noaa.gov>
> Sent: Saturday, April 19, 2008 9:10 AM
> Subject: Re: [Coral-List] Long term change in Eritrean reefs: past,  
> present,future
>
>
>> Dear Tom, Pete, Mark and listers,
>>
>> Good to hear from you all. Thanks a lot Pete for bringing up this  
>> encouraging article on the status quo of Eritrean reefs for  
>> discussion. Tom, I also appreciate you mentioned Gordon Sato and  
>> the Manzanar Project in light with their work on mangrove  
>> rehabilitation. The Eritrean reefs are certainly diverse,  
>> resilient and robust given the pressure they are under - both  
>> natural and anthropogenic.  Strictly speaking, however, they are  
>> not "pristine" but their near pristine conditions are good enough  
>> to many of us, I'd reckon. I am glad Charlie Veron's assessment   
>> came to those same conclusions. This is really a breath of fresh  
>> air to many if not all of us.
>>
>> Although pressure from tourism and coastal development, at this  
>> point in time, is nominal the reefs are not completely free from  
>> pressure from especially the heavy fisheries by commercial fleets.  
>> Places like Eritrea are unquestionably stuck with a seemingly  
>> irreconcilable dilemma: on one hand in trying to conserve these  
>> reefs for present and future use and on the other in trying to  
>> aggressively use these resources for the common good and  
>> betterment of their citizens.
>>
>> By discussing issues pertinent to conservation in such a milieu I  
>> believe we can promote awareness of such world heritage as the  
>> Eritrean reefs and devise prospects for sustainable development.  
>> At this juncture, I can't help but thank Pete Raines and Gordon  
>> Sato for their leadership and efforts, past and present, in  
>> biodiversity conservation.
>>
>> Cheers,
>> Marco Pedulli
>>
>>
>>
>>
>>
>>> Date: Fri, 18 Apr 2008 10:08:16 -0400
>>> From: Thomas Goreau <goreau at bestweb.net>
>>> Subject: Re: [Coral-List] Long term change in Eritrean reefs: past,
>>> present, future
>>> To: "Tupper, Mark (WorldFish)" <M.Tupper at CGIAR.ORG>
>>> Cc: Ivan Nagelkerken <i.nagelkerken at science.ru.nl>, coral-list
>>> coral-list <coral-list at coral.aoml.noaa.gov>, ECOCEAN
>>> <ecocean_label at yahoo.com>, Michael Arvedlund
>>> <arvedlund at speedpost.net>, Gordon Sato  
>>> <manzanarmangrove at hotmail.com>
>>> Message-ID: <82B4F438-435B-4194-B588-DEC4B665E0DB at bestweb.net>
>>> Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed
>>>
>>> Dear Mark,
>>>
>>> A paper by Gordon Sato in a book I am editing for the UN mentions
>>> that the local fishermen are claiming increased catches after
>>> mangrove establishment. Like you, I'd suspect the usual mangrove
>>> dwellers. I think that Gordon has mainly word of mouth from local
>>> fishermen, but he has close contacts with the Eritrean fisheries
>>> department, and can let you know who might be following up on this.
>>>
>>> I'm sure you know Ivan Nagelkerken's recent great recent paper that
>>> resolves the controversy on whether mangrove juvenile fish  
>>> habitat is
>>> due to strucutural protection by the mangrove roots per se, or the
>>> fact that they are in shallow water habitat, or because the  
>>> shoreline
>>> is remote from large reef predators (notwithstanding the barracudas
>>> that love to lurk near mangrove roots)? By making artificial  
>>> mangrove
>>> roots and placing them in many different habitats he found the
>>> highest juvenile fish recruitment on outer reef slopes, proving that
>>> it is the shelter itself that is the key factor.
>>>
>>> We similarly notice extraordinary juvenile fish recruitment to
>>> electrical reef restoration projects, and we are joining forces with
>>> the Ecocean group to release juveniles and larvae into such habitat
>>> to short circuit juvenile mortality and rapidly restore reef
>>> fisheries (that is to say, if anyone will fund this kind of work,
>>> which is far from clear). It is now obvious that MPAs don't work
>>> unless they protect prime quality habitat, and where that is gone
>>> only habitat restoration will restore fisheries. Now all we need  
>>> is a
>>> few decades more for policymakers and funders to realize that the  
>>> MPA
>>> fad can't work unless habitat restoration is the prime focus of
>>> coastal fisheries management. Until then they will continue to throw
>>> good money after bad and pray for "resilience" and that global
>>> warming and pollution will disappear by themselves.............
>>>
>>> Best wishes,
>>> Tom
>>>
>>>
>>> On Apr 18, 2008, at 8:22 AM, Tupper, Mark (WorldFish) wrote:
>>>
>>> > Dear Tom and listers,
>>> >
>>> > I have been following this thread with some interest after doing a
>>> > review of GEF-funded coral reef-related projects, which included
>>> > work in Eritrea. I was wondering the same thing as Tom - if the
>>> > reefs are so great, why are the fisheries not so great?
>>> >
>>> > Taking a snippet from Tom's post:
>>> > "I am one of the scientific advisors to the Manzanar Project,  
>>> which
>>> > has planted vast mangrove forests along Eritrean desert shorelines
>>> > where no mangroves ever existed, using Gordon Sato's innovative
>>> > approaches, and these have resulted in large increases in catches
>>> > by local fishermen, which would presumably imply that the reef
>>> > fisheries habitat is not as pristine as claimed."
>>> >
>>> > I was wondering if anyone knew what species these large catch
>>> > increases involved. If they were Gerreids or Lutjanids, some
>>> > species of which have mangrove-dependent life history stages, or
>>> > other fishes that might be wholly dependent on mangrove habitats,
>>> > then the increases would result simply from the increase in
>>> > available mangrove habitat. In that case, the amount of reef
>>> > (pristine or otherwise) would have no bearing on the catch.
>>> > However, if the increased catches contained a high proportion of
>>> > reef fish which maybe using mangrove prop roots as an alternative
>>> > form of structure/shelter, that might imply (as Tom said) that
>>> > there was insufficient suitable reef habitat.
>>> >
>>> > Tom, do you have any data on those increased catches, or would you
>>> > know someone who does?
>>> >
>>> > Cheers,
>>> >
>>> > Mark Tupper
>>> >
>>> >
>>> >
>>> >
>>> > -----Original Message-----
>>> > From: coral-list-bounces at coral.aoml.noaa.gov on behalf of Thomas
>>> > Goreau
>>> > Sent: Fri 4/18/2008 1:35 AM
>>> > To: coral-list at coral.aoml.noaa.gov
>>> > Cc: Gordon Sato
>>> > Subject: [Coral-List] Long term change in Eritrean reefs: past,
>>> > present,future
>>> >
>>> >> Long term change in Eritrean reefs: past, present, future
>>> >
>>> > I'm wondering why this very interesting article on Eritrea's reefs
>>> > just posted on the list server ends with the word "Advertisement"?
>>> > Could that be because every place in the world is advertising  
>>> their
>>> > reefs as "pristine" to attract tourists, whether that is true  
>>> or not?
>>> >
>>> > In the early 1960s the late Thomas F. Goreau did a lot of work on
>>> > Eritrean reefs, especially in the Dahlak Arhipelago. To his  
>>> surprise
>>> > he found the coral cover was very low. That was where he  
>>> discovered
>>> > the feeding mode of Acanthaster planci, extruding its stomach to
>>> > digest coral tissue, something he had not seen when he  
>>> collected the
>>> > first live Acanthaster intact at Bikini Atoll in 1947, when they
>>> > lived deep in crevices and only came out to feed at night (they  
>>> were
>>> > previously known from dredge haul samples and nothing was known of
>>> > their ecology). He attributed the low coral cover he found in  
>>> Eritrea
>>> > to chronic infestation by Acanthaster swarms. This was long before
>>> > the "first" outbreaks that he, Rick Chesher, and Rick Randall  
>>> studied
>>> > in the Western Pacific in the late 1960s. I have all the photos  
>>> and
>>> > scientific specimens, but I have never found anyone interested in
>>> > comparing them to look at long term change.
>>> >
>>> > Now if the report below is correct, and I completely trust Charlie
>>> > Veron''s assessment, this implies that the severe Acanthaster
>>> > predation that was there 4-5 decades ago has disappeared  
>>> completely
>>> > and permanently? If so, that is truly remarkable, and deserves  
>>> much
>>> > further work because all across the Indo-Pacific we have been  
>>> seeing
>>> > recurrent infestations and nobody has any idea how to control  
>>> them.
>>> >
>>> > It should also be noted that mapping the Bleaching HotSpots (sensu
>>> > Goreau & Hayes, 1994) shows that there should have been several  
>>> very
>>> > severe bleaching events there in recent decades. I have several  
>>> times
>>> > alerted researchers in Eritrea to look out for them, but never
>>> > received any field confirmation. The long term sea surface
>>> > temperature trends for Eritrea (which I can supply on request)
>>> > suggest that worse lies ahead since maximum temperatures in this
>>> > region is warming considerably faster than the global ocean  
>>> average
>>> > (Goreau et al, 2005).
>>> >
>>> > Another interesting point about this article below is that if the
>>> > reefs are so good everywhere in Eritrea, why have the fisheries
>>> > declined? I am one of the scientific advisors to the Manzanar
>>> > Project, which has planted vast mangrove forests along Eritrean
>>> > desert shorelines where no mangroves ever existed, using Gordon
>>> > Sato's innovative approaches, and these have resulted in large
>>> > increases in catches by local fishermen, which would presumably  
>>> imply
>>> > that the reef fisheries habitat is not as pristine as claimed.
>>> >
>>> > It is delightful to hear that Eritrean reefs are "pristine",  
>>> but this
>>> > raises very important issues of long term historical changes, and
>>> > almost certainly does not imply immunity to the challenges that
>>> > global warming will throw at them. More work is clearly needed.
>>> >
>>> >> Thomas J. Goreau, PhD
>>> > President
>>> > Global Coral Reef Alliance
>>> > 37 Pleasant Street, Cambridge MA 02139
>>> > 617-864-4226
>>> > goreau at bestweb.net
>>> > http://www.globalcoral.org
>>>
>>> Thomas J. Goreau, PhD
>>> President
>>> Global Coral Reef Alliance
>>> 37 Pleasant Street, Cambridge MA 02139
>>> 617-864-4226
>>> goreau at bestweb.net
>>> http://www.globalcoral.org
>>>
>>>
>>>
>>> ------------------------------
>>>
>>> Message: 3
>>> Date: Fri, 18 Apr 2008 11:58:38 -0400
>>> From: Phil Dustan <dustanp at cofc.edu>
>>> Subject: Re: [Coral-List] Long term change in Eritrean reefs: past,
>>> present, future
>>> To: "Tupper, Mark (WorldFish)" <M.Tupper at CGIAR.ORG>
>>> Cc: coral-list at coral.aoml.noaa.gov, Thomas Goreau
>>> <goreau at bestweb.net>, Gordon Sato <manzanarmangrove at hotmail.com>
>>> Message-ID: <4808C52E.90000 at cofc.edu>
>>> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>>>
>>> Mark and Tom'
>>>     Have a look at Gordon Sato's work on the Manzanar Project -  
>>> which
>>> was opposed by GEF COnsultants. Might shed some light on the issues.
>>> http://www.manzanarprojectfoundation.com/
>>>
>>>  Phil
>>>
>>> Tupper, Mark (WorldFish) wrote:
>>> > Dear Tom and listers,
>>> >
>>> > I have been following this thread with some interest after  
>>> doing a > review of GEF-funded coral reef-related projects, which  
>>> included work > in Eritrea. I was wondering the same thing as Tom  
>>> - if the reefs are so > great, why are the fisheries not so great?
>>> >
>>> > Taking a snippet from Tom's post:
>>> > "I am one of the scientific advisors to the Manzanar Project,  
>>> which has > planted vast mangrove forests along Eritrean desert  
>>> shorelines where no > mangroves ever existed, using Gordon Sato's  
>>> innovative approaches, and > these have resulted in large  
>>> increases in catches by local fishermen, > which would presumably  
>>> imply that the reef fisheries habitat is not as > pristine as  
>>> claimed."
>>> >
>>> > I was wondering if anyone knew what species these large catch  
>>> increases > involved. If they were Gerreids or Lutjanids, some  
>>> species of which > have mangrove-dependent life history stages,  
>>> or other fishes that might > be wholly dependent on mangrove  
>>> habitats, then the increases would > result simply from the  
>>> increase in available mangrove habitat. In that > case, the  
>>> amount of reef (pristine or otherwise) would have no bearing > on  
>>> the catch. However, if the increased catches contained a high >  
>>> proportion of reef fish which maybe using mangrove prop roots as  
>>> an > alternative form of structure/shelter, that might imply (as  
>>> Tom said) > that there was insufficient suitable reef habitat.
>>> >
>>> > Tom, do you have any data on those increased catches, or would  
>>> you know > someone who does?
>>> >
>>> > Cheers,
>>> >
>>> > Mark Tupper
>>> >
>>> >
>>> >
>>> >
>>> > -----Original Message-----
>>> > From: coral-list-bounces at coral.aoml.noaa.gov on behalf of  
>>> Thomas Goreau
>>> > Sent: Fri 4/18/2008 1:35 AM
>>> > To: coral-list at coral.aoml.noaa.gov
>>> > Cc: Gordon Sato
>>> > Subject: [Coral-List] Long term change in Eritrean reefs: past,  
>>> > present,future
>>> >
>>> >
>>> >> Long term change in Eritrean reefs: past, present, future
>>> >>
>>> >
>>> > I'm wondering why this very interesting article on Eritrea's reefs
>>> > just posted on the list server ends with the word "Advertisement"?
>>> > Could that be because every place in the world is advertising  
>>> their
>>> > reefs as "pristine" to attract tourists, whether that is true  
>>> or not?
>>> >
>>> > In the early 1960s the late Thomas F. Goreau did a lot of work on
>>> > Eritrean reefs, especially in the Dahlak Arhipelago. To his  
>>> surprise
>>> > he found the coral cover was very low. That was where he  
>>> discovered
>>> > the feeding mode of Acanthaster planci, extruding its stomach to
>>> > digest coral tissue, something he had not seen when he  
>>> collected the
>>> > first live Acanthaster intact at Bikini Atoll in 1947, when they
>>> > lived deep in crevices and only came out to feed at night (they  
>>> were
>>> > previously known from dredge haul samples and nothing was known of
>>> > their ecology). He attributed the low coral cover he found in  
>>> Eritrea
>>> > to chronic infestation by Acanthaster swarms. This was long before
>>> > the "first" outbreaks that he, Rick Chesher, and Rick Randall  
>>> studied
>>> > in the Western Pacific in the late 1960s. I have all the photos  
>>> and
>>> > scientific specimens, but I have never found anyone interested in
>>> > comparing them to look at long term change.
>>> >
>>> > Now if the report below is correct, and I completely trust Charlie
>>> > Veron''s assessment, this implies that the severe Acanthaster
>>> > predation that was there 4-5 decades ago has disappeared  
>>> completely
>>> > and permanently? If so, that is truly remarkable, and deserves  
>>> much
>>> > further work because all across the Indo-Pacific we have been  
>>> seeing
>>> > recurrent infestations and nobody has any idea how to control  
>>> them.
>>> >
>>> > It should also be noted that mapping the Bleaching HotSpots (sensu
>>> > Goreau & Hayes, 1994) shows that there should have been several  
>>> very
>>> > severe bleaching events there in recent decades. I have several  
>>> times
>>> > alerted researchers in Eritrea to look out for them, but never
>>> > received any field confirmation. The long term sea surface
>>> > temperature trends for Eritrea (which I can supply on request)
>>> > suggest that worse lies ahead since maximum temperatures in this
>>> > region is warming considerably faster than the global ocean  
>>> average
>>> > (Goreau et al, 2005).
>>> >
>>> > Another interesting point about this article below is that if the
>>> > reefs are so good everywhere in Eritrea, why have the fisheries
>>> > declined? I am one of the scientific advisors to the Manzanar
>>> > Project, which has planted vast mangrove forests along Eritrean
>>> > desert shorelines where no mangroves ever existed, using Gordon
>>> > Sato's innovative approaches, and these have resulted in large
>>> > increases in catches by local fishermen, which would presumably  
>>> imply
>>> > that the reef fisheries habitat is not as pristine as claimed.
>>> >
>>> > It is delightful to hear that Eritrean reefs are "pristine",  
>>> but this
>>> > raises very important issues of long term historical changes, and
>>> > almost certainly does not imply immunity to the challenges that
>>> > global warming will throw at them. More work is clearly needed.
>>> >
>>> >
>>> >> Thomas J. Goreau, PhD
>>> >>
>>> > President
>>> > Global Coral Reef Alliance
>>> > 37 Pleasant Street, Cambridge MA 02139
>>> > 617-864-4226
>>> > goreau at bestweb.net
>>> > http://www.globalcoral.org
>>> > _______________________________________________
>>> > Coral-List mailing list
>>> > Coral-List at coral.aoml.noaa.gov
>>> > http://coral.aoml.noaa.gov/mailman/listinfo/coral-list
>>> >
>>>
>>> -- 
>>> Phillip Dustan  Ph.D.
>>> Department of Biology
>>> College of Charleston
>>> Charleston   SC  29424
>>> (843) 953-8086 voice
>>> (843) 953-5453 (Fax)
>>>
>>>



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