artificial reefs vs. coral reefs

[James Wiseman]

Craig,

I believe you are in fact asking two separate questions in this post:

1: "Is it reasonable to assume that coral reefs are potentially capable of
sustaining similar quantities of fish biomass, or whether this phenomenon is
attributable to the particular attractive feature of artificial reefs."

2: Do artificial reefs that are maintained as harvest refugia hold more fish
than a reef where fishing is permitted.

Answer 1 - If the artificial reef is designed correctly, it's certainly
reasonable to compare its holding capacity to that of a natural reef, and
vice versa.  Is an artificial reef better at "aggregating" _fish_?  That is
a
good question I don't have the answer to.

Answer 2 - This seems self-evident as a resounding YES.

The reason I see the second question posed is your observation:

"Coral reefs in Puerto Rico are considered quite overfished, and the density
of fish described on the artificial reefs is never seen."

In my mind, it's certainly necessary to "factor out" marine protected areas
when comparing artificial reefs to natural reefs.  Do you have a MPA that
you
can observe and compare to the artificial reef location?  If so, I'd be very
interested to hear your results.

I hope this is of some assistance and raises further discussion.

James Wiseman
www.reefs.org

-----Original Message-----
From: Craig Lilyestrom [mailto:craig at caribe.net]
Sent: Thursday, February 07, 2002 1:51 PM
To: Coral-List at coral.aoml.noaa.gov
Subject: artificial reefs vs. coral reefs

Recently, someone commented to me on the enormous quantity of fish
biomass present around some artificial reef units (concrete
structures designed by a well-known company) in Puerto Rico.  He did
not estimate the biomass, but rather described having to almost push
the fish out of the way with his hands, in order to swim forwards.
The units were installed several years ago.  The precise location of
these units is not public knowledge, and hence fishing effort on them
is minimal or non-existent.

My question is whether it is reasonable to assume that coral reefs
are potentially capable of sustaining similar quantities of fish
biomass, or whether this phenomenon is attributable to the particular
attractive feature of artificial reefs.  Coral reefs in Puerto Rico
are considered quite overfished, and the density of fish described on
the artificial reefs is never seen.

I'd appreciate any enlightenment.

--Craig
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