In Reply to: Re: Easy Reader article about local artificial reefs...by Phil! posted by BCH DIVR on February 12, 2014 at 20:20:24:

I've noticed that algae, especially kelp doesn't seem to attach to artificial reefs as easily it does to rocks. I don't know if it has anything to do with the substrate, but artificial reefs are almost always found offshore where they are subject to currents. Kelp stands a better chance of growing closer to shore where it has some protection. The animals associated with kelp forests are absent or in small numbers on the artificial reefs.
I have noticed a larger number of smaller invertebrates on the artificial reefs. Perhaps they thrive due to the lack of predators found in a natural reef.