'%Healthy Reefs for Healthy People - A Guide to Indicators of Reef Health and Social Well-being in the Mesoamerican Reef Region%'%by Melanie McField and Patricia Kramer%

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Status

Data Needs

Comparisons of bioerosion at healthy and degraded

We recommend examining the frequency of bioeroding

sites in the MAR have not been conducted. However,

organisms in coral rubble along well-known nutrient

it is hypothesized that bioerosion will be higher at

gradients and at some of the AGRAA 2006 sampling

reefs exposed to higher nutrient levels.

locations. This non-destructive and relatively simple

method has been field tested in Barbados and should

In Barbados, a "polluted reef" had approximately

be replicated in the MAR. The abundance of visible

41% of the Porites rubble pieces invaded by clionid

bioeroders on live coral could be assessed at the

sponges, whereas a comparable unpolluted reef had

same study sites to compare the results of the two

24% invaded33. Results from a Cayman reef showed

methods and help determine which method may be

sewage-impacted reefs can have five times more

preferable. These data would help establish reference

bioerosion than comparable non-impacted reefs34.

values for a bioeroders indicator.

In the Australian Great Barrier Reef, offshore reefs

If Diadema urchins ever return to former densities of

tend to have less bioerosion than do the inshore

~10 urchins/m2, they too should be considered as one

reefs, which are closer to continental runoff35.

of the primary bioeroders on reefs.

Eric Mielbrecht