I have been sport fishing on my own boat for over 10 years now. Many friends captain commercial fishing boats here in Newport, and have expressed their interest having me run their boats. What type of schooling/certification do I need, to get my captain's license?
You really don't need any licensing or training to begin captaining a commercial fishing vessel. The Coast Guard will require a training course in First aid, CPR, emergency response, drug testing for crew members in case of certain accidents at sea, etc, and you will need to find out when these trainings are held so that you don't get cited during a boarding at sea, but you can begin captaining a commercial fishing vessel prior to those trainings.
The Clatsop Community College Maritime Training Center in Astoria offers courses in many aspects of maritime vessel operation and training and can certify you for a licence in merchant marine operation. This training and certification would be valuable if you ever decided to pursue a career in the merchant marine outside of fishing.