[Coral-List] Artificial reefs

Todd Barber reefball at reefball.com
Wed Mar 10 21:52:24 EST 2004

Hi Bob,

Cheers, Cheers...I agree with you totally.  (Well, I think there are some
successful artificial reefs, but they are not that common).  One thing
artificial reef managers have done is to push the envelope to try to get
that learning curve down as quickly as possible.  Perhaps that is one reason
they are creating a bit of contraversy.  In the last decade, we have gone
from throwing trash in the water and calling it a reef to designed reefs
with very complicated and special systems to better accomidate marine
life...sure, likely we'll laugh at this like we laugh today at people
throwing tires in the water as reefs, but we are at least a generation in
science ahead with designed reefs over trash disposal.  I believe coral
propogation, more natural looking designs, and specific species "tuning" to
get population densities and species diversity in sink with natural reefs is
the next generation for artificial reefs and praticitioners are working hard
at accomplishing this.  Forgive us for our bumps and mistakes getting there.

-Todd Barber

----- Original Message ----- 
From: "Robert Bourke" <rbourke at OCEANIT.COM>
To: <jmcmanus at rsmas.miami.edu>; "'Coral List'"
<coral-list at coral.aoml.noaa.gov>
Sent: Monday, March 08, 2004 3:46 PM
Subject: RE: [Coral-List] Artificial reefs

> John - and All;
> >From my viewpoint, artificial reefs don't work NOW for two primary
> a) The Tragedy of the Commons, and
> b) Lack of knowledge and experience in coral reef management
> However, the same could have been said for forestry or fisheries
> 100 years ago.  Granted, there are some colossal examples of terrible
> forestry and fisheries management, but there are also numerous examples of
> these resources being managed well today - in ways that could not have
> foreseen 100 years ago.  I'm sure that 100 years from now, coral reef
> resource managers will look back with a wince and wry smile at our meager
> attempts to create artificial reefs.... so many are dismal failures.  But
> only through these attempts and learning through these failures will we be
> able to develop appropriate management strategies.
> The real challenge is to develop a system that can learn from past
> management experiences and to collapse the 100-year learning curve down to
> few decades.
> Bob Bourke
> -----Original Message-----
> From: John McManus [mailto:jmcmanus at rsmas.miami.edu]
> Sent: Saturday, March 06, 2004 2:00 PM
> To: 'Coral List'
> Subject: [Coral-List] Artificial reefs
> Hi all,
> I believe that artificial reefs are potentially valuable tools for coral
> reef conservation. However, most are probably not. Based on some
> fascinating emails I have received, I think it important to explain my
> reasoning. Unfortunately, the explanation is long, and so read on only
> if you have a strong interest in all this.
> Within the first several years or so, none of the newly-settled fish on
> an artificial reef can possibly have a positive impact in terms of
> alleviating fishing pressure. They will be too young. So, here are two
> of the issues with respect to fishing.
> 1. How do you manage the reef in such a way that people do not use it to
> increase fishing pressure on area stocks within the first five or so
> years until the settled fish can reach the age of first reproduction?
> Generally, the structure will have to be in an area in which fishing is
> strictly and successfully prohibited for several years.
> 2. How do you demonstrate that after that time, the majority of fish
> caught in the artificial reefs are those that settled there as
> juveniles, especially given that there is usually incontrovertible
> evidence (as in question 1) that the artificial reefs do indeed attract
> fish from natural habitats? And, consequently, how many fish per unit
> area of artificial reef do you then allow people to remove by fishing
> (basically some very small fraction of the ones that settled there
> several years before and managed to survive all those years despite the
> high mortality imposed by the in-migrant fish)?
> I've seen the impressive thousands of juveniles that often settle on
> artificial reef. However, I'm also aware that only a few of those ever
> survive to the age of first maturity. As Polovina pointed out very
> elegantly more than a decade ago, an area is overfished only once its
> natural stocks have been reduced by over 40 - 60% or more. Why then
> would anyone think that there is a need to provide more habitat space in
> order to get more fish? In most cases, if you want more fish, reduce
> fishing. Do not make it cheaper for people to catch fish, as this
> usually leads to fish stock depletion beyond the point where continued
> overfishing leads to zero net profit.
> Let's suppose you have an artificial reef of 10 by 10 meters, and that
> after 5 years, there is one 5-year-old fish per sq. meter. (ignore the
> 1, 2, 3 and 4-year-olds, you'll need them in the following years). Let's
> assume that that species has just exceeded its age of first reproduction
> at five years, and is ready to start harvesting. There are now 10 x 10
> or 100 fish to be harvested in that year. You cannot even keep one
> fisher's family fed with the fish that grew up in that artificial reef.
> The truth is, however, that the artificial reef will probably be
> supplying far more than 100 fish per year. It will be getting them from
> surrounding areas -- that is, unless the decline in fish stocks have
> already made that source negligible.
> Show me a situation where an artificial reef will not lead to
> overfishing. Show me the fishing restrictions and the evidence that they
> will be followed. Then show me that parts of it will not lift up during
> large storms and destroy natural habitat. Show me that it won't pollute.
> Show me that you have not diverted public funds from conservation
> efforts, and that the expected returns justify the investment. Show me
> that these and other harmful effects have been accounted for and I will
> be public ally supportive.
> I think artificial reefs, including those enhanced with electric
> current, could increasingly be important ways of helping reefs to
> recover from losses of corals (perhaps replacing them with
> bleaching-resistant corals), and possibly fish. However, they should
> meet the above criteria. Very few do.
> Cheers!
>  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) 361-4814
> Fax (305) 361-4910
> www.ncoremiami.org
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