Honestly there is very little demand for either staghorn or elkhorn in the American aquarium hobby. This is no doubt due in part to the fact that these two corals are not particularly attractive at typical aquarium sizes. The key exerpts i got from the NOAA listing is that
"We determined the major stressors (i.e.,
disease, elevated sea surface
temperature, and hurricanes) to these
species’ persistence are severe,
unpredictable, likely to increase in the
foreseeable future, and, at current levels
of knowledge, unmanageable."
I dont know that this will really change much a far as the protection status of these corals but it may elevate their visibility in terms of protection legislation and funding.