[Coral-List] Artifical Reefs

[John McManus]

Hi Kristin,

We have had a lot of discussions about this in the past few years. You might
want to check out the Coral-list archives.

>From my standpoint, if you put in a structure that is non-polluting, does
not fall apart, is not a menace to navigation, etc. and prevent it from
being fished, then it may be more good than bad. That may be the case for
improving snorkel and dive tourism in some areas (such as keeping tourist
damage away from unusually sensitive reef areas). 

If one allows fishing, it is usually pretty easy to demonstrate
mathematically that the benefits from providing new fish habitat are far
outweighed by the detriment of the devices acting as fish attractors which
exacerbate overfishing by gathering otherwise scattered fish together where
they can be more easily caught. 

However, artificial reefs can also be used to close areas to trawl fishing
by snagging the nets, as is done in South East Asia with old buses, concrete
structures, etc. That is probably a good thing, where bottom trawling is the
overwhelmingly dominant means of fishing. Bottom trawling is still the most
habitat-destructive marine activity of mankind -- a systematic shaving away
of vital sponge, calcareous algae, and coral patch communities across huge
areas of the world's continental shelves.  

Of course, there are artificial reefs for the purpose of rejuvenating coral
populations. As long as they have a low relief, they may not also be a
concern from the fishing standpoint. However, once they are high enough off
the bottom to significantly attract harvestable fish, then the fishing does
become a concern. That would be similar to operating to save someone's
kidneys, while at the same time destroying the liver. 

Similarly, artificial reefs for preventing beach erosion may or may not
cluster fish together for easy harvesting, depending on their design and
deployment. 

Fortunately, there are lots of coral planting and beach prevention reef
operations that are relatively low relief, and some with high relief in
areas where fishing is prohibited.

Cheers!


John

John W. McManus, PhD
Director, National Center for Coral Reef Research (NCORE)
Professor, Marine Biology and Fisheries
Coral Reef Ecology and Management Lab (CREM Lab)
Rosenstiel School of Marine and Atmospheric Science (RSMAS)
University of Miami, 4600 Rickenbacker Causeway, Miami, 33149
jmcmanus at rsmas.miami.edu      http://ncore.rsmas.miami.edu
 Phone: 305-421-4814   Fax: 305-421-4910

  "If I cannot build it, I do not understand it."
              --Richard Feynman, Nobel Laureate



 
-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Kristen Nunn
Sent: Friday, November 13, 2009 6:06 PM
To: Coral-List at coral.aoml.noaa.gov
Subject: [Coral-List] Artifical Reefs

Do you have any ideas of whether or not artificial reefs are more harmful
than helpful?
Thank you.

Kristen
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