[Coral-List] Diadema Workshop Report

[Brad Rosov]

Coral Listers,

The Nature Conservancy, in partnership with The University of Miami's
Rosenstiel School of Marine and Atmospheric Sciences and the National Fish
and Wildlife Foundation hosted the Diadema Workshop on March 19-20 this past
year.  Workshop participants included coral reef biologists, echinoderm
biologists, ecologists, geologists, and resource managers from the U.S. with
representation from universities and non-governmental agencies from 11
countries or territories.

The purpose of the Workshop was to review the historic and current status of
the long spined sea urchin, D. antillarum, across the region and to review
what is known about its natural population dynamics.  A secondary objective
of the Workshop was to explore the scientific basis for restoring urchin
populations as a possible proactive management approach to increase
herbivory on coral reefs in which D. antillarum densities remain low.

Key Workshop recommendations include:
  1.. Develop a comprehensive, region-wide protocol to be used by an
existing or new monitoring program to designed to collect D. antillarum
density data with a focus on locating "hot spot refugia" of currently
elevated densities. The protocol should include measures of habitat
rugosity, D. antillarum settlement patterns, population distribution (by
size classes, habitat, depth, temperature, and salinity regime), careful
observations in crevices, and D. antillarum predator abundance. Measures of
coral reef recovery (i.e. decreases in algal composition) should be
monitored as D. antillarum begins to recolonize the reefs.
  2.. Proceed with small-scale experimental D. antillarum restoration
projects with an experimental component (see recommendation #4).
  3.. Conduct studies on the microbial community associated with healthy D.
antillarum and develop a specimen collection and handling protocol in
anticipation of future die-offs.
  4.. Support experimental work to test key aspects of D. antillarum biology
and ecology; i.e. test rates of predation on D. antillarum (including the
effect of micropredators on juveniles), investigate D. antillarum larval
supply at various geographic locations, determine settlement requirements,
habitat preference, and the optimum number of D. antillarum needed to
facilitate successful coral recruitment and to adequately remove algae but
not erode the reef framework.
The full report is available for download on AGRRA's website
(http//:mgg.rsmas.miami.edu/agrra/index/html) and on Conserve Online.
Please contact me directly for printed copies of the report (in a condensed
version).

Cheers!

      Brad Rosov
      Marine Conservation Program Manager

      brosov at tnc.org
      (305) 745-8402 Ext. 102
      (305) 745-8399 (Fax)

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