[Coral-List] Artificial reefs

Todd Barber reefball at reefball.com
Wed Mar 10 21:38:02 EST 2004

Hi Lad,

Very nice points...you should weight in on Monday mornings more often!  One
of the things that one learns in "artificial reefs 101" is that the most
important first step is to understand the exact goals of the project before
you design a reef.

-Todd Barber

----- Original Message ----- 
From: "Lad" <lad at reef.org>
To: <coral-list at coral.aoml.noaa.gov>
Sent: Monday, March 08, 2004 12:00 PM
Subject: RE: [Coral-List] Artificial reefs

> HI John and All,
> I feel compelled by a strange Monday morning wind to weigh in on the AR
> discussions.  Sorry if I'm taking up space in your in-box!  For those
> interested in the continuing dialog, I feel that an important point is
> overlooked regarding management of artificial reef (AR) sites.
> John, all of your points are very well taken and I agree with almost all
> what you presented.  Two issues that warrant further discussion are,
> what is the purpose of an artificial reef and, second, if the purpose is
> conservation, then we should consider applying some of the same
> techniques to artificial reefs that we use on natural reefs.
> Relative to the first point, some artificial reefs are used for purposes
> other than conservation (i.e. recreational diving, science, fishing).  If
> the purpose is to provide increased catch per effort, then ARs may be the
> way to go (considering the effect on overall stocks, of course).  If the
> purpose is to provide a wreck diving recreational opportunity, then
> placement of an AR may be a viable solution. If the purpose is to provide
> structure for manipulative study, then ARs may serve that purpose. It is
> important to remember that all ARs do not serve all purposes and that many
> purposes may not warrant the use of ARs considering the related impacts.
> Relative to the second point (conservation), it seems that much discussion
> revolves around the effect of ARs in attraction vs. production.  I would
> like to point out that attraction may not always be a bad thing.  The
> concern is that fish are removed from an AR, not that fish are attracted.
> The activities allowed on the AR should be the real issue, not simply the
> effect of those activities.  It seems that in many recent discussions, it
> almost a given that ARs will include fishing activities and few are
> addressing the potential of zoning ARs as no-take.
> I would present that a no-take AR would attract fish, serve as habitat for
> benthic organisms, provide non-extractive recreational opportunities and
> opportunities for science without the negatives of increasing catch.  Of
> course, your points of enforcement are well taken, though this is an issue
> facing no-take natural reefs as well.  Stability of the structure is
> dependent upon design, construction and placement.  And opportunities do
> exist for funding of ARs that would not otherwise be available for
> conservation programs (i.e. DOT funding for removal of concrete bridge
> rubble, MARAD ship money).
> I am not the greatest fan of artificial reefs, but I am also not ready to
> write them off as a complete negative either.  I believe there are
> possibilities for AR use, even in conservation, that satisfy specific
> purposes, if the design, construction, and placement of the structure, as
> well as the management of the site, follow the purpose.
> Thanks for the forum!
> Lad
> **********************************************
> Lad Akins
> Executive Director
> Reef Environmental Education Foundation (REEF)
> 98300 Overseas Hwy
> Key Largo  FL 33037
> www.reef.org
> -----Original Message-----
> From: coral-list-bounces at coral.aoml.noaa.gov
>  Behalf Of John McManus
> Sent: Saturday, March 06, 2004 7:00 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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