Well a few things come to mind.
1. Is your tank just set up? That may be the cause for the high nitrates, it may not be through its cycle.
2. What do you have in your tank that could be causing your bio load to spike ?
3. There are several ways to "Catch" Damsels. Some are not so nice. Once you get your nitrates under control you can "Rent" an agressive fish to catch your damsels. I.E. a trigger of some sort. Or you could go the other route and try to catch them when you feed them. You may have to just resort to taking all your lr, coral, etc. out to catch them.