"Legal" definition of a coral reef?

Sat Jan 13 22:25:05 EST 2001

Here is my draft definition for an article in an encyclopedia that will come
out next year.
'The term "coral reef" commonly refers to a marine ecosystem in which a
prominent ecological functional role is played by scleractinian corals. A
"structural coral reef" differs from a "non-structural coral community" in
being associated with a geomorphologically significant calcium carbonate
(limestone) structure of meters to hundreds of meters height above
surrounding substrate, deposited by components of a coral reef ecosystem.
The term "coral reef" is often applied to both types of ecosystem or their
fossil remains, although many scientists, especially geomorphologists,
reserve the term for structural coral reefs and their underlying limestone.'

The limits on what is and is not a part of a given coral community can be
more difficult to define than most people realize. In the worst case, one
has scattered clumps of coral that gradually become increasingly dense
toward a central area. Some worn footpaths through grass have the same
character. Defining the width of the path can be challenging. The situation
is similar to that of defining the length of a coastline. In a general
sense, there is no right answer. One can only define the length of the
coastline in terms of a particular choice of measuring stick. Alternatively,
one can describe the coastline in terms of fractals, although this is useful
only for certain purposes. Similarly, one could choose a density for
delineating the coral patch, but one would have to couple it with a
particular way (especially scale) of measuring the density (or set of scales
or fractal index).

Given the above definition, the depth would not matter. Some people like
terms such as bioherm, but but most people would tend to think of a bioherm
as a form of the popular concept of a coral reef. I don't mind the use of
the term, as long as it is clearly defined when used. I think the
'wave-breaking" concept should be dropped entirely from coral reef
definitions, and we should accept that the term "coral reef" should imply
little or no relationship to the unqualified nautical term "reef". That gets
us around having to define two nearly identical ecological -
geomorphological constructions as different just because one has sunk a few
meters lower than the other (e.g. the Palawan subsurface "barrier coral reef
system", which looks much like the GBR but rarely comes to within 10 m of
the surface).

John

_________________________________________________________

John W. McManus, PhD
Director, National Center for Caribbean Coral Reef Research (NCORE)
Rosenstiel School of Marine and Atmospheric Sciences (RSMAS)
University of Miami, 4600 Rickenbacker Causeway
Miami, Florida 33149.
jmcmanus at rsmas.miami.edu
Tel. (305) 361-4609
Fax (305) 361-4600

 -----Original Message-----
From: 	owner-coral-list at coral.aoml.noaa.gov
[mailto:owner-coral-list at coral.aoml.noaa.gov]  On Behalf Of Nani Kai
Sent:	Monday, January 08, 2001 6:03 PM
To:	coral-list at coral.aoml.noaa.gov
Subject:	"Legal" definition of a coral reef?

A simple question;  What IS a coral reef?  Or perhaps more importantly,
what is it Not?  (But first let me say that I did review the discussion on
"what is a reef" in last May's coral-list.)

With the great amount of attention that coral reefs have received in the
past few years, regulators are (at last!) coming to the realization that our
precious marine resources need protection.  My concern is that this pendulum
of regulation may be swinging a bit too far to the left.  I think that
everyone reading this list would agree that coral reefs represent a resource
that merits our protection.  I don't think, however, that everyone would
agree specifically about how to define the "coral reef" that we are trying
to protect.

A "reef" may be clearly defined in strictly nautical terms as it relates
to ship traffic without any reference to corals or other living marine
resources.  Similarly "coral" (or coral communities) may be appropriately
defined in biological terms leaving little room for academic argument.
It is only as the terms are combined that an increased level of meaning
emerges in the definition to include an interwoven ecological matrix of
habitat complexity, species diversity, and fragility.  But with the
increasing presence of regulators and lawyers dealing with coral reef
issues we are rapidly approaching a time where a working (read: legal)
definition of a "coral reef" will be necessary.

Please consider the following two situations.

Given a flat basalt substrate in 10 meters (just below keel depth) of water,
at what coral density does a 1 hectare area become a coral reef?  Does
surface rugosity, species composition, or colony age play a role in this
designation?

Given a shoreline area, depth from 0 to 2 meters, within 50 feet of shore,
do the same definitions apply?

Please forward any answers or comments directly to the list.

I'll do what I can to follow up with a summary to see if we can develop a
consensus definition.

Thanks for your input.

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