Fw: Additional Data From Beqa
carlson at soest.hawaii.edu
Tue Apr 11 15:48:26 EDT 2000
Here's is another report from Fiji. Also, apparently the western side of
Viti Levu has not been affected as of 4/11/00.
----- Original Message -----
To: Bruce Carlson <carlson at soest.hawaii.edu>
Sent: Monday, April 10, 2000 2:01 PM
Subject: Additional Data From Beqa
....I believe of more value would have been the report I am sending now
which includes information from Sunday's surveys. You mentioned this is of
scientific interest which I assume that this is where you are directing the
information. I do realize of course that it is on the web which is shouting
it to the world. The report below should be considered as correct if there
is any conflict with the information sent in the rushed messages I sent you.
Please get this information on record to replace any of the information in
the messages. I have carefully pulled notes and dates of problems starting
to occur, to put together a more accurate picture. Also I had whoever was
diving with me review assessments to see if they felt the same about what
they were viewing.
March 24: We notice a few species of corals showing signs of bleaching.
Mostly Hydnophora. These are in areas with a lot of river run off and where
bleaching occurs more frequently.
April 3: I receive a message from Bruce Carlson about unusually warm water.
A day later I see Ed Lovell's report on bleaching in the western side of
Beqa lagoon and various parts of Fiji. I check a couple of dive sites but
only see the same situation as March 24. I dive one reef very near here and
it looks quite OK just the odd coral with light bleaching.
April 7: Reports come in from local divers that some of the coral is turning
white in the lagoon areas of Beqa and Deuba.
April 8: We check the outside reef of Beqa lagoon on the south and south
east side bordering deep water well away from the passes. About 5% of the
coral at most was dead. Around 75% of the corals were alive but were
showing bleaching from light to severe, with around 20% looking relatively u
nbleached and healthy. Dropping down the reef, we found that betwen 8 and
10 metres there was a distinct improvement in the health of the corals. The
deeper corals in 10 meters or more were the least affected, showing little
or no sign of bleaching, and looking healthy. A large stretch of reef of
over 10 kilometers was spot checked with consistent results. This was
followed up by a check of the inshore reef mentioned above that is very near
my house on April 5th. The situation there had changed dramatically. About
10 % of the coral on top of the reef was dead, with all the acropora
showing signs of bleaching. Again, the corals at depth were healthier.
April 9: I checked the top of the reef on the south western part of Beqa
lagoon. The areas I checked were between 1 meter and three meters deep at
high tide. I was there at mid tide. It was an outgoing tide taking water
from the lagoon. There was large surf pushing in water from the outside of
the reef. It was mid day, hot and sunny. Temperature of the water was
between 86.3F degrees and 85.3F degrees depending on location. There was a
higher percent of dead corals in this area, approximately 10% to 20%. Most
corals were in various stages of bleaching. The deeper the water the less
the effect even though it was only a meter or two difference in depth. I
then checked the outside of the reef on the western side. Temperature there
at between five and ten meters was 84F degrees. The coral there more
resembled the outside of Beqa lagoon on the south eastern side. Less actual
dead coral and mostly bleaching coral with some healthier corals at 10
meters and more.
It is important that although most corals are bleaching now, corals that
have actually died seem more prevalent in certain species. So when rough
percents are given above they do not reflect that some species are really in
difficulty and have died where as others there is still a high percentage
alive and they may still survive if some cool water comes in quickly. I have
listed a few species below and how they appear to be doing as of August 9.
Acropora: Most of the dead acropora is in the sprawling colonies of loose
branching species, such as A. nobilis and A. pulchra. These can be up to 50%
dead in some areas, particularly the shallow lagoon areas. Only 5% of other
species such as humilis, samoensis, robusta, subulata, and aculeus were
dead, although a high proportion were showing light to extreme bleaching.
Note that I have a lot of difficulty to identify these species. The only
healthy ones with no or little bleaching are at 10 meters or more.
Pocillopora: There are some dead pocillopora approximately 5% with P.
damicornis more affected. Most damicornis are suffering from bleaching.
>From 8 meters depth onward there are many healthy ones. P. verrucosa tended
to be less affected by bleaching, with some healthy ones in shallow waters,
and quite a few healthy at 10 metres or more.
Seriatopora: Almost all appear to be bleaching at shallower than 10 meters.
However, there were large healthy populations at 15 meters and more on the
outside of the reef.
Fungia: Mostly healthy with a very small percent (<5%) exhibiting bleaching.
Caulastrea: Shallow water ones are almost all bleached. Deeper water ones
have bleaching showing but some colonies are still not bleached.
Favia & Platygyra: A large proportion were bleached, although very few dead
colonies were observed.
Galaxea: Very few dead, but some bleaching (30% to 40%) starting to take
Lobophyllia: Most are bleached but even in shallow water I have not observed
any dead ones.
Turbinaria: Mixed observations, with some shallow water areas showing
significant bleaching, while in other areas they remain healthy and
Sarcophyton spp: Widespread bleaching occuring, having rapidly deteriorated
between March 26 and April 9. Virtually no dead sarcophyton observed.
To sum this up. As in Ed Lovell's report I have seen the rapid nature of
the effect where one week all is well and the next week there is rapid and
widespread bleaching. Also my survey of the outside of the reef on April 8
bears out his observation that widespread color remains on the outside of
the reef. Although I am in shock as to the rapid change in what is
occurring on a reef I have spent many thousands of hours diving on over the
last sixteen years I will not give up hoping that cool water will arrive
before it is too late.
In a perverse way it is fortunate that this has struck when the reef
population is so strong. The present population of coral in the Beqa-Deuba
area is the best I have ever seen. We have gone through an unusually calm
period of no major cyclones coming this way to destroy the reef for six
years. And it has been almost a decade since we have had a devastating
crown of thorns invasion. This has all combined to give a high coral
density. Given some cooling in water temperature I am hopeful that if the
mortality is not too extreme, we could be left with a population at not too
far from the long term average level.
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