Guy's;
There is an alternative and has been for a long time to the old poisonous copper and tin based anti fouling paint.
There is a product called "Epaint". It's been around for years and the Coast Guard uses it.
http://www.epaint.com/
I didn't realize this until I just read the testimonials on the web site but my neighbor on Welch uses this on his sail boats!...
http://www.epaint.com/testimonials
Dan