[Coral-List] coral list post: Diadema antillarum

Dokken, Dr. Quenton qdokken at gulfmex.org
Fri Apr 25 11:20:06 EDT 2008

We used the same technique described by J. Ware.  After sunset when D.a.
comes out to graze is the key. 
-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of John Ware
Sent: Friday, April 25, 2008 8:14 AM
To: Dan Dalke-Fac/Staff
Cc: coral-list at coral.aoml.noaa.gov
Subject: Re: [Coral-List] coral list post: Diadema antillarum

Drew and Dan,

Well, since I didn't see any other replies:

D.a. are typically sparse, altough I understand there is a comeback at 
DBML.  What we have done in the past is to lay out a transect line using 
a 50 m tape.  We laid our tapes along depth contours in order to 
determine a depth effect.  Then two divers swim along the line, one on 
each side, with a 1 m pvc pipe.  Each diver counts the number of D.a. 
within 1 m of the tape using the pvc pipe as a guide, thus surveying 100 
m**2.   This is simple and fast.

Sounds like you may be taking people without much diving experience and 
maybe even less night diving experience.  D.a. are very good at hiding, 
so all surveys should be done after the sun goes down.  Without good 
buoyancy control, there could be some close encounters with the D.a. 
which, believe me, are VERY painful.  Do some research on first aid and 
take along the required stuff - DBML may help you there.


Dan Dalke-Fac/Staff wrote:

>Dear coral listers,
>This is Drew Fozzard. I am a senior at Lovett, and am currently
>doing an independent research project with my Marine Biology
>teacher.  Along with 11 other students, we will be going to
>Discovery Bay Marine Lab in Jamaica with a  research diving
>class.  We are interested in doing a project involving the
>population of the reef urchin Diadema antillarum.  I was
>wondering if anyone had any information or suggestions for
>monitoring the numbers of Diadema on the different reefs at
>Discovery Bay. We are taking 1/2 m and 1 m quadrants with us.
>Drew Fozzard
>alfozzard at lovett.org
>Dan Dalke
>Upper School Science Department Chairman
>The Lovett School
>404-262-3032 ext. 1520
>ddalke at lovett.org
>Coral-List mailing list
>Coral-List at coral.aoml.noaa.gov

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