[Coral-List] Artificial Reefs

Thomas Le Berre thomas at seamarc.com
Fri Oct 18 04:03:08 EDT 2013

Dear Dennis Hubbard,


Thanks for sharing your experience of your past restoration success. I fail
to understand why you now seem to be considering this effort as a youth
mistake. I agree with you that any types of structure will attract fish (in
fact I even saw recently an exhibit at the Monterey Bay Aquarium where fish
inhabit different pieces of junk on the bottom of the tank, which I thought
was quite daring). I also agree that there may be a lot of things we don't
know about the impacts of the artificial reefs. But I would also say that
there is a lot of things that we do know and observe. You empirically
determined the physical effects your rocks were having on wave propagation
currents etc. and adapted to achieve what seems to be a desirable result.
Physical effects are of course more direct to observe than ecological ones,
and even though in time they may alter considerably an area (large events
etc.), a good balance seem to have been restored through luck or skill. 


Change in the ecological factors of course take longer to be felt, but it
seems that 20 years after, there were more fish and more corals. I would
think that there is a necessary spill-over effect, more fish, more corals,
more larvae, etc.(and if this is used for tourism purpose and not fished,
that's again a bonus I guess). I won't go into whether fish were attracted
or recruited to your structures. I have seen both depending on sites and
species. Anyway, we will agree that on the ecological point of view, your
project was also beneficial and certainly that the situation now is better
than what is was before you started your project (or at least that any
decrease in diversity, productivity cannot be assigned to that activity, but
maybe global changes or other "unknown factors"). 


Having been successfully through a major storm, we could also say that the
area is more resilient and adapted to climate change. (The storm on the dump
would definitely have been a disaster). In addition, there is a better
recreational value, possibly keeping the crowds away from the natural reef.


What other major unknown factors could there have been that would condemn
your project?


Now, imagine that this project didn't occur, do you think this would have
prevented the developer to do whatever to try and improve their situation,
regain a beach etc.probably given it to a contractor with no feeling
whatsoever for the marine life (yes, this is almost always the case), cheap
and easy, but which would constant recurring works and meddling with the
environment, never letting it settle, etc... In developed countries maybe
the legislation prevents developers to take the situations into their own
hands without the necessary guidance and knowledge, but in many places,
trial and error prevails.and the ecological side of things is always


At the stage we are at, I am wondering if the shortsightedness would not be
to deny this reality, acknowledge "their" shortsightedness as a fact. We
need to develop better solutions to the problems caused by coastal
developments. Of course: there will be more people, there will be more
tourists, there will be more pressure to have more infrastructure. I don't
believe that wisdom will suddenly sink in politicians brains overnight, and
even then they all have their crowd of voters to please. Yes, it may be that
not only your project, but the human race as a whole is doomed to failure at
the start, and yes, we are going to have to display last minute (in
geological terms) reactions to the discovery of petrol engines and
penicillin. I would say that this is more tragic than pathetic.


Minor successes after minor successes is already going forward. And it does
develop a know-how that can be shared, developed etc... It eventually
develops an economy and more environmentally minded people can find related
jobs and help change the present dynamic. I can think of many people
educated in marine fields not finding any opportunities to work, what a
waste of possible effort. If there is more employment in the sector, surely
all the associated research funding will grow as well.Right now, I feel that
taking a refuge behind the "unknown factors" is the root cause for many bank
funded developments to altogether do nothing at all for the ecology in coral
reef areas, thereby saving dollars that would otherwise do very well into
this part of the economy. Eager contractors are at times being discouraged
to even think about it by local authorities as a result.


Far from being a failure that you seem to be ashamed of, I feel your project
should be a case study (and I am quite sure that you would love to have
yearly monitoring data of the site). I don't question your verdict about
your own work and accept your experience, but sincerely, I fail to be
convinced that development of a practical know-how to successfully "meddle"
with the ecological side of things during coastal developments needs to be
altogether written off. In fact, I find it quite appealing and possibly
necessary. Finally, I am wondering if the denegation of your own work and
success story is the result of rational thinking and field observations or
intense peer pressure.


This is a long mail, thanks for reading this far.


Best regards, 



Thomas Le Berre

Managing director

Seamarc Pvt. Ltd.

www.reefscapers.com, www.marinesavers.com




From: Dennis Hubbard <dennis.hubbard at oberlin.edu>

Subject: Re: [Coral-List] Artificial Reefs

To: "Rachel D'Silva" <rachdsilva at yahoo.com>

Cc: "coral-list at coral.aoml.noaa.gov" <coral-list at coral.aoml.noaa.gov>


      <CAFjCZNZP011hzEJDtrhr=fpQ7HiveuQQZPnkDcPTPqFnHXwoQA at mail.gmail.com>

Content-Type: text/plain; charset=ISO-8859-1


I think there are two extremes to this discussion. First, if you put ANY

topographic structure on an open bottom, it will attract fish (they don't

care - look at all the fish around those deep-water nuclear disposal

sites). Also, corals will grow on it. However, the other side of the coin

is that any structure you place into the environment will have some impact.

Some of that will respond to the laws of physics (diffraction, diversion of

flow, etc.) but much of it will respond to factors we largely do not

understand. So the question is whether we should take the time to learn

those factors so we can engineer the environment.


About two decades ago, we placed ca. 100 rocks (5-7,000 lbs each) onto a

terrace that had been the site of a flourishing *Acropora palmata* reef in

the 60s (we didn't know this when we started the project). It had been

killed not by disease but by dredge pipes that were raked across the reef

to move sediment from the bay to cover the municipal dump for this island

of St. Thomas (it was being decommissioned). Ironically, the owner of the

dump who wanted to sell the land for development purposes was also the

first director of the newly created Department of Conservation and Cultural

Affairs (talk about irony.... and I can't lay out the half of it here).

When we were called in, a huge hotel complex had just been built  and

someone suddenly realized, "We have no beach!" This reflects a common

development perception that the natural system can be engineered so all

they have to do is throw money at a consultant like they do for financial



In this case, historical research revealed that this site had always had a

wide beach and we could identify no realistic reason for it to not be there

today. Further research into DPNR records revealed the bizarre situation I

just laid out.... the reef had been mechanically destroyed and the loss of

protection caused a wholesale exit of beach sand back into the hole).  We

ultimately decided that, while we could not replace the biological

function, we might replace the physical function by very carefully placing

these large stones in a way that allowed wave energy to pas through (i.e.,

it was not an impermeable structure but rather large boulders that broke up

incoming waves and partially protected the shore). We also set it up so

that strong unidirectional flow persisted behind the ridge (all that water

coming in between the blocks had to exit - creatinf strong shore-parallel

flow. The net result was that the new artificial beach persisted even after

Hurricane Marilyn) and water quality remained acceptable behind the loosely

scattered rocks. Our ultimate decisions on rock placement were based on

climbing up on the hotel roof and looking at how the 10 rocks we'd placed

each day affected wave refraction and diffraction patterns (very

empirical). To keep them in place, e had 3-inch holes pre-drilled in the

rocks and then pinned them to the bottom by drilling into the underlying

substrate and inserting steel rods and marine cement into the rocks and the

underlying substrate).


When I visited the site years later, corals (even *Acropora palmata*) had

colonized on the rocks - and the fish had moved in. The corals we had

transplanted to the fron of thi area were still doing better than the

natural ones nearby. This had become a reasonably popular snorkeling spot

due to the easy access from the adjacent beach.


Having set up this rosy scenario, I do not advocate the sense that physical

structures are anything more than last-minute reactions to poor decisions

in the past. While our structure created protection and made the hotel more

viable, this was not a substitute for even a mediocre natural structure

and, while the history of the area is amusing, it is also pathetic.I have

always wondered how much these kinds of minor "successes" just feed the

perceptions of developers that they can rely on the engineering/ecological

community to come in and move things around a bit to cover their

shortsightedness. I consider our project as one that was doomed to failure

from the start even though the financial picture was improved and the

ecological side was at least made no worse. I vowed to never do one of

these projects again and can happily report that the slate is still clean.





On Tue, Oct 1, 2013 at 3:54 PM, Rachel D'Silva <rachdsilva at yahoo.com> wrote:


> Hey Coral List,

> I'm looking for articles/papers with design and engineering options for

> major functioning breakwaters (shallow) combined with reef restoration. I

> like the idea of sections of the breakwater having a design component that

> can be head started with coral fragments as well as functioning as a

> potential dive/snorkel site. The standard designs and structures will

> function as FADs...but in over fished waters.. this really isnt enough.


> I really appreciate any ideas/info you might have.



> Rachel

> 'Unless someone like you cares a whole awful lot, nothing is going to get

> better. It's not'.- The Lorax



> ________________________________

> _______________________________________________

> Coral-List mailing list

> Coral-List at coral.aoml.noaa.gov

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Dennis Hubbard

Chair, Dept of Geology-Oberlin College Oberlin OH 44074

(440) 775-8346


* "When you get on the wrong train.... every stop is the wrong stop"*

 Benjamin Stein: "*Ludes, A Ballad of the Drug and the Dream*"


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