[Coral-List] sea urchin removal to prevent bioerosion

[Anders Knudby]

Hi Clement,

1.5 years ago we started a project on the reef at Chumbe Island, Tanzania,
where we regularly removed all D. setosum from a number of plots on the
reef. We didn't use cages because we were interested specifically in
exclusion of urchin only, not in exclusion of all similar-sized animals
(e.g. large herbivorous fish). The project was meant as a pilot study, to
see what effect we could expect from a full-scale removal of all urchins on
the reef, as had been suggested by some. To my knowledge results are
inconclusive so far, but may be firmed up and made available later.

I would be interested to know your thoughts on the use of cages. Did you
design a cage that would include/exclude only Diadema, or how do you control
for other animals' response to the cages? Or are Diadema the only animals
relevant for your study in the area?

Cheers,
Anders Knudby

knudby at gmail.com