Look for, and join, the "Placencia News & Happenings" group on Facebook. Volunteer opportunities get posted there. There is probably a similar group for Hopkins as well. Other options you could consider contacting directing are: Placencia Humane Society and Placencia Rotary. You should be able to contact both through Facebook.
If you have not figured it out yet, Facebook is how things get done here in Belize!
Shane Kenny IL Correspondent for Belize