Diver needs advice re. measuring sediment

Ursula Keuper-Bennett howzit at turtles.org
Sat Jul 12 13:45:47 EDT 1997

Aloha CORALers,

Every summer my husband and I visit Maui, Hawaii to dive a site that a
community of Hawaiian green sea turtles calls home.  We have made over a
thousand dives here and have watched helplessly the deterioration of the
reefs in this area.

On any day three out of four turtles you'll see here have fibropapilloma
tumours (a disease that is now a major threat to the recovery of this
threatened species).  Of the surviving resident animals (turtles we have
known since the early 90's) over 90% have or have had the disease.

Scientists are working hard to determine the etiology and ultimately the
cure for fibropapilloma disease.  Progress however is limited by funding...

>From 1977 (when I first visited this dive site) to 1988, the corals and
reefs here were topnotch.  In fact, this area was listed as a Top Ten Maui
snorkelling site.

1989 saw the first Cladophora algae bloom.  By 1990 many of the corals in
the area had been browned and smothered.  From that year on, such seaweeds
as Hypnea musciformis dominated and underwater our area had a vegetative
fuzz growing on any hard substrate including the many corals which were now
just browned fuzzy lumps.

1991 had the worst Cladophora bloom ever and in 1993 after a torrential
rain, the rich soils of West Maui got washed into the ocean leaving a red
smear all the way out to the 50 foot depths (five miles up and down the

All through that time (1988-1993) we dived with the turtles and watched the
prevalence of disease go from one out of four to its present levels.  

For more information please see:     http://www.turtles.org/honohist.htm

Since we arrived at the end of June, every single dive has been murky and
there is red silt over much of the bottom.  I've been told they've had a
rainy spring and I believe them.  It has rained the last few days and on
one dive (we do two dives a day rain or not), we actually SAW a wall of red
come down from the north (upcurrent).  

Over a summer my husband and I will get separated about three times.  We've
already managed that number because of the haze and poor visibility.
They're putting in a new development just across the street and the soil
there is exposed.  Above that are three open red fields waiting for
pineapple to be planted.

Today there is a slight swell and it has removed the Hypnea from the beach.
 When that happens the stuff gets pulled out to 30 foot depths and gets
trapped on the reefs.  But it also means the sediment on the ocean floor
now gets barfed up into the water...ensuring murky diving.  

Yes, I know we could move to cleaner places.  Either area to the north and
south of us has excellent diving.  But we aren't here for the diving -- we
are here for the turtles.  They can't up and move like we can.  They get to
live in this soup all the time.  There is an OBSESSIVE need to know how
they're faring from year to year.

At our site is the largest oldest turtle we have ever seen.  He's been
resident to the area since at least 1992 and he was old even then.  He's
OLD as AIR!  No one knows how old "old" is for a sea turtle.  Well Zeus has
developed fibropapilloma tumours in the last 10 months since we saw him
last!  Imagine.  ALL his life free from the disease and now he too is a

If the disease runs its course, this grand patriarch will die from it.

For more information on Zeus see:   http://www.turtles.org/zeus.htm

All we get to do is watch these turtles contract the disease, get sicker
and then "disappear".  Oh we can photograph/videotape the conditions here
but it doesn't seem to be enough.  And here is why I have come to you.

We had "sediment rain" again yesterday.  This one seemed to come OFF the
ocean floor and then envelope us.  The turtles' shells get reddish and we
get this soil taste through our regulators.

We are now at a stage where we want to QUANTIFY the amount of sediment here
but we are both laypeople and don't know where to begin.  We thought of
just  bringing jars out to various sections along our dive site and leaving
them there for the year til our return in '98.  We thought of buying an
aquarium type net and dragging that along on one dive just to get an idea
of how much silt is in the water.

If the cost is not too prohibitive we would be prepared to order REAL
equipment from a scientific supply house.  It is just we don't know the
best thing to use.  Any advice on "drift sediment" measuring for both short
and long term is MUCH needed and would be really appreciated.

Also, if you know of any areas where there is a high rate of fibropapilloma
disease among the resident turtles I want to hear about it.  We are keeping
records of such sites.

At this time I also want to thank James Hendee and NOAA for providing and
maintaining this mailing list.  I learn a lot monitoring it and benefit
greatly when I do need to leave a message here.

Mahalo for reading this and aloha
              ^               Ursula Keuper-Bennett
             0 0              Email: howzit at turtles.org
    /V^\            /^V\             
  /V     Turtle Trax    V\    http://www.turtles.org 
 /                        \
When you study members of another species, when you
habituate them in the wild, when you begin to understand
the intimate details of their private lives, and then 
you learn that the population or whole group is sliding
towards extinction, what do you do?  In good conscience,
you must defend them...
          \       /                                
          /  \ /  \       --- Birute M.F. Galdikas
         /__| V |__\  

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