the multiple watermarks are absolutely necessary. Its unbelievable how many times they steal my art and they upload it as theirs. maybe this will make you see my point? ...jthogan58.deviantart.com/art/T…
Its unfortunate yes, but if they are going to go through the trouble of removing one they will go to the trouble of removing five or six.
They didn't remove your watermark on that specific piece as it is, it is easily seen that it is stolen and it appears they have credited you in the title, blatantly showing that it isn't their own work and is in fact yours. In fact it seems their gallery is just a gallery of works that do not belong to them, probably just because they enjoy the pictures and don't want them to get lost, or locked away, as Deviantart is hardly a professional website anymore. They also have several more of yours, if you were not aware. If you want it removed all you have to do is report it really.
What I was trying to get at is the watermarks distract from the beauty of your work. You're work is absolutely beautiful, but the watermarks are so distracting I can not fully enjoy it. I'm not telling you to change your process, or do it differently. This is just my personal view, and take it with a grain of salt. From one professional to another keep doing what you're doing, its gorgeous. I just wish the watermarks weren't so distracting to me.