If you are 16 to 24 you could start off as a fishing boat deck hand. You can do a Diploma in Sea Fishing while getting experience at sea.
When you have experience you can learn and train on the job to go on to become a skipper.
There are no set entry requirements for this route but it may help you to get in if you have:
- 2 or more GCSEs at grades 9 to 3 (A* to D), or equivalent, for a level 2 course