Table 7 summarises the assignment of ‘‘Reef Performance Scales’’ to the 30 case
studies based on the definitions supplied in Table 5. These are based on the
information presented in the relevant paper. As can be seen, only two of the case
studies [19,39] successfully met all of their objectives. These respective case studies
refer to the use of vessels and concrete modules for the prevention of illegal trawling
in the Mediterranean Sea, and the use of concrete reefs to provide habitat for spiny
lobster populations in mitigation for a marina construction in Biscayne Bay, Florida.
These are both practical initiatives that have yielded readily definable results in terms
of effectiveness.
Although 20 of the case studies are weighted as +1/+2, this shows that many
artificial reef initiatives do not meet their objectives in full, with only limited success,
albeit significant success in certain cases. It seems appropriate in these instances that
the studies would benefit from more detailed review and management procedures,
although this is difficult in terms of planning for unexpected events. For research
studies, the data produced on the whole will merely be of relevance in a localised
context, withonly general inferences possible in terms of examining artificial reefs in
a wider geographical context. In the majority of instances, the interaction between
local environmental conditions, local ecology and the specific reef design make for
very unique systems, which may not be reproducible elsewhere.
The scale of ‘‘0’’ has been assigned to 7 of the case studies, mainly reflecting the
inconclusive nature of the presentation of the reef and its performance, both in
practical and researchterms. This also reflects a lack of adequate monitoring and
management plans. Although certain projects appear to have successfully met some
of their objectives, e.g., disposal of excavated rock material [18], this is not fully
discussed in terms of acceptability, impact of placement and the provision for future
monitoring. Such projects are therefore awarded this scale as a means to
demonstrate the need for more detailed investigation