A critical factor affecting the ability of a fragment to successfully recruit is the substrate type where the fragment is deposited (Lirman and Fong 1997b). Bak and Criens (1981) found that A.palmata fragments fuse too ther, living elkhorn fragments faster than to any othertype of substrate. In Florida, elkhorn fragments landingon rubble substrate had a higher survivorship and alower percent tissue loss than those deposited on relictreef substrate (Lirman and Fong 1997b). At the Fortuna Reefer grounding site, fragments were secured to the relict reef substrate or to dead, standing elkhorn skeletons. Those fragments attached to skeletons were expected to exhibit enhanced survivorship associated witha reduction in scouring, improved water circulation,increased light exposure, and possibly a reduced exposure to benthic predators and pathogens. Contrary tothis hypothesis, fragments secured to the reef substrate had a higher survivorship than those attached to elkhorn skeletons. Although fragments on the reef substrate were larger, the percentage of tissue remaining after 2 yearson survivors did not differ between the two attachment locations. The differences in survivorship are likely tohave resulted from a higher rate of mortality experiencedby those fragments placed in contact with the invasive sponge Cliona spp., which was found commonly overgrowing elkhorn skeletons and less frequently on the substrate