The US Fish and Wildlife Service has some info on cormorants. Pretty interesting.
Pepper is right, once the lake level drops below full again, you'll see those cormorants park themselves out at the shoals again, along with the seagulls. As far as getting rid of any kind of bird on the property, I have noticed that whenever the Black Cat area's resident bald eagle comes around, he scares the other birds away. He really seems to enjoy it, too... often doing it for no apparent reason, on a fly-by. With a wingspan around 4 or 5 feet (from what I've seen of him) most other birds in this area are half his size at best. So if you find a way to attract bald eagles, that could be the answer to any problem you have with any other bird!
Here's the link to USF&W Cormorants page:
http://www.fws.gov/migratorybirds/is...akes_facts.htm