Take the watermark off, protect your work under various creative commons licenses and when you find out that people have used the image, then you threaten legal action. In the mean time keep high resolution images off of the internet so people can't print them for proper commercial use.
Note I'm not saying bait people into thinking your work is free to use and then hit them with a "my normal charge is £500 per 6x4" email like some photographers do, just recognise that a watermark is largely useless for protective purposes.
Ultimately, any watermark that's going to do a half decent job of protecting an image is going to have a bigger effect in ruining the image. Watermarks in photography come down to increasing awareness in the way that Jaime Ibarra does it - yes they're easily removed, but that's not the point. What'll protect your images is just not having 12mp copies of every image available online.
Finally:
Watermarks - useful for advertising/getting the word out, less useful for protection
Resolution - in real terms, this is your protective tool along with a decent legal backup as a last resort. Nobody using a 960*640 image off of the internet is going to be paying significant money for an actual print.
Very nice images as well, under the watermark. Tbh, until you're at Lara Jade/Chase Jarvis levels of success, I don't think people stealing your images should be of huge concern - and they don't even use watermarks... I use them as examples as they're internet photographers as opposed to long-since established photographers who've got agencies to deal with all the copyright issues.