[Coral-List] RE: Artificial Reefs-Response again (long, sorry!)
jmcmanus at rsmas.miami.edu
Mon Mar 8 11:04:10 EST 2004
Although my note was not specifically targeted at Reef Balls, I am
delighted that you have responded to the challenges of the criteria I
I would not, of course, be entirely convinced that the Reef Ball
complexes are meeting the criteria until I saw the statistics to back up
the claims. Artificial reefs are human interventions, and should be put
in only after environmental impact assessments. Those should include
quantitative assessments of the local state of fishing, projections of
the impacts of fishing on the artificial reefs on the local stocks,
analyses of potential damage during storms, certifications of lack of
toxins, the potentials of the artificial reefs to disrupt traditional
fishing practices, and so forth. The EIAs should be posted on the
Internet and available for comment before approval. Naturally, the EIAs
should be tied to a periodic review process and adaptive management.
Note that some form of prior study is usually required within the US.
However, for some reason, the fish stock assessment sides have often
been severely lacking (again, for ARs in general, including old ships,
busses and trolley cars).
Of course, while you are correct about the high mortality in the egg
stage, the mortality between larvae and juvenile is still very high, and
does not begin to taper off from a rapid to a reasonable descent for
most reef fish until a few months post settlement (alas, it is hard to
put the graph into an email).
It is also important to keep in mind that no reef can be considered to
be healthy and resilient if the fish community is not healthy and
resilient. There is increasing evidence that a reef with a disrupted
food web is likely to be far more sensitive to nutrient loading than an
intact one (nutrients in a healthy reef tend to be channeled up through
the food web instead of remaining at the primary production level).
Thus, if a human intervention enhances overfishing, there is never going
to be a way to justify the intervention in terms of making the reef
healthier, no matter how much biomass one generates or how many other
species are enhanced.
As for the likelihood of the ARs adding to fishing success, if I were a
person trying to make a living by fishing, and I knew of an artificial
reef packed with fish, I know exactly where I would go fishing. The
reason, of course, is that I would catch more fish per unit effort on
the AR (note that ARs have led to serious conflicts in some areas, as
they often disrupt traditional fishing patterns and rights). Increasing
catch per unit effort in an overfished situation is exactly what should
be avoided. So, if a government is going to permit the deployment of an
artificial reef in its waters, and there is an overfishing problem (as
there is in at least 70% of the world), then it should ensure that
fishing is limited or banned on the AR. If a ban is not to be selected,
then the levels of limits should be based on quantitative stock
analyses. In many cases, FAO, recommends that fishing effort be targeted
at the Maximum Economic Yield Point. This can be estimated in many
fisheries by many available methods. Of course, fishing should be
similarly limited everywhere, but obviously putting in something that
attracts fish is going to make it easier to catch them, and thus greatly
increases the need for the regulation.
So, coastal management is a complicated business, and artificial reefs
are part of either the problem or the solution. Putting them in without
careful prior analyses and compensatory coastal management strategies,
particularly with regard to the local fishing situation, will usually
result in their being part of the problem.
If you have an EIA that includes the appropriate fishery analyses, I
would enjoy reading through it. However, in the case of the recent large
AR complex, I would also hope to see a thorough analysis of some other
factors, such as an analysis of local potential storm wave spectra and
lift potentials relative to the Reef Balls, even with the extra
weighting you described. I have seen solid concrete blocks the size of a
double bed shift around and do substantial damage even at 60 feet during
I would prefer to discuss ARs in general and not go into specific cases
(such as Reef Balls) on coral list, but will provide more specific
analyses and discussions if needed. Perhaps to show that ARs are not the
only good thing with potentially bad effects, someone will start up a
thread about mariculture on reef flats. Almost everything one does in
coastal management has pros and cons, and these must always be dealt
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
From: Todd Barber [mailto:reefball at reefball.com]
Sent: Monday, March 08, 2004 9:29 AM
To: coral-list at aoml.noaa.gov; jmcmanus at rsmas.miami.edu
Cc: kathy kirbo
Subject: Artificial Reefs-Response from Todd Barber
I would like to respond to your presumption that artificial reefs may
not be valuable tools because the newly settled fish are not enough to
offset fishing pressures.
There are a few factors that you have overlooked in your analysis.
1) Artificial Reefs don't necessarily change fishing pressure (i.e.
people will still fish on natural reefs if there are no artificial reefs
to fish on, so there is not necessarily a net loss to fish by the act of
building a reef). This, of course, only holds true when artificial
reefs do not change the ease at which a fisherman can catch fish. For
this reason our Foundation has generally opposed the use of shipwrecks
as artificial reefs when WHEN USED FOR FISH STOCK ENHANCEMENT OR
BIOLOGICAL GOALS because taller artificial reefs can reduce fishing
effort/increase catch rates. (Note: Shipwrecks may have some merit when
the goals of a project are scuba diving or tourisum oriented and not
biological. There are some studies that show in some places that
shipwrecks can reduce diving pressure on natural reefs and we don't
oppose their use for these specific goals.)
2) Artificial reefs (or natural reefs) don't just create new settled
fish, they provide habitat for adult fish (habitat can increase the
heath and growth rates of adult fish). And also, artificial reefs (or
natural reefs) provide a great deal more environmental resources than
just fish. (corals need substrate to rebuild natural reefs, inverts,
algaes, and thousands and thousands of other species of life use reefs
as habitat). Your argument that because we are taking fish from the
ocean means there is plenty of habitat is flawed for two reasons. 1)
Mankind has destroyed fish (and reef) habitat at an alarming rate...we
could not possibly build enough habitat to replace that which has
already been lost or degraded. 2) If it is man's desire to take fish,
we must provide ways to give fish an advantage in reproduction and
growth so that populations remain at healthy stock levels. (I.E.
providing specific habitats that get fish through life cycle bottlenecks
such as has been done with designed artificial reefs that have preditor
exclusion devices in their design).
3) Of the thousands of juviniles that settle on reefs that you describe,
many more make it to first maturaty that you may think. The really high
mortality is from eggs to juviniles...ever wonder why a fish releases
millions of eggs in a spawn and not just a couple? And again, the more
habitat that is present, the more the likelyhood that these juvinile
fish will make it to maturity.
from your message, (and I put my answers in CAPS to follow your
question...not because I am "screaming")
"Show me a situation where an artificial reef will not lead to
overfishing." LIMIT ARTIFICIAL REEF DESIGN TO DESIGNS THAT DO NOT
REDUCE FISHING EFFORT/CATCH AN THEN IT IS IMPOSSIBLE FOR ARTIFICIAL
REEFS TO LEAD TO OVERFISHING.
"Show me the fishing restrictions and the evidence that they will be
followed." THIS IS AN ISSUE FOR ALL WATER WHERE FISH ARE PRESENT AND
MUST BE MANAGED BY THE STAKEHOLDERS (I.E. GOVERNMENT) AND USING OR NOT
USING ARTIFICIAL REEFS WILL NOT CHANGE THIS.
"Then show me that parts of it will not lift up during large storms and
destroy natural habitat." LIMIT ARTIFICIAL REEF DESIGN TO STRUCTURES
PROVEN TO BE AS STABLE AS NATURAL REEF HEAD.
"Show me that it won't pollute". LIMIT ARTIFICIAL REEFS TO STRUCTURES
THAT USE ONLY INERT MATERIALS.
"Show me that you have not diverted public funds from conservation
efforts, and that the expected returns justify the investment." PUBLIC
FUNDS ARE NOT DIVERTED, THEY ARE COMPETED FOR AND AWARDED TO EFFORTS
DEEMED BY THE PUBLIC TO JUSTIFY EXPECTED RETURNS. IF ARTIFICIAL REEFS
WERE NOT PROVIDING THAT RETURN, THEN PUBLIC FUNDS WOULD DRY UP. IF
CONSERVATION EFFORTS ARE NOT BEING FUNDED AT ADEQUATE LEVELS, THEN WE
NEED TO DEVELOP TECHNIQUES FOR CONSERVATION THAT JUSTIFY THE EXPECTED
RETURNS BETTER SO THAT THE PUBLIC WILL AWARD MORE FUNDING TO
Show me that these and other harmful effects have been accounted for and
I will be public ally supportive.
HERE IS WHERE YOU MAKE YOUR BEST ARGUMENT AND I FULLY AGREE, AS WITH ANY
MANAGEMENT TOOL, ARTIFICIAL REEFS ARE ONLY AS GOOD AS THE
PEOPLE/AGENCIES/NGOs/SCIENTISTS WHO DESIGN, PLAN, BUILD, MONTIOR AND
MANAGE THEM. AND ANY ENVIRONMENTL INTERVENTION...EVEN CONSERVATION
EFFORTS CAN HAVE MAKE MISTATKES BUT I THINK WE CAN ALL AGREE THAT WE
MUST CONTINUE CONSERVATION EFFORTS AND HABITAT RECONSTRUCTIONS AS BEST
AS TECHNOLOGY ALLOWS OR MORE AND MORE HABITATS WILL BE LOST WORLDWIDE
AND WE WON'T HAVE MUCH LEFT TO CONSERVE OR REBUILD
AND FINALLY, I AGREE THAT ALL NEW ARTIFICIAL REEF TECHNIQUES SUCH AS
ELECTRIC CURRENTS SHOULD BE TESTED, STUDIED, AND IF THEY CAN MEET YOUR
EXPECTATIONS AND THAT OF ARTIFICIAL REEF PROFESSIONALS, THEY COULD BE
ANOTHER TOOL AVAILABLE TO HELP.
Reef Ball Foundation, a 501(c) 3 Publicly Supported Non-Profit Charity
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