Work experience aboard vessel protecting marine species (10)
I believe the answer is:
internship
'vessel protecting marine species' is the definition.
I can't tell whether this definition defines the answer.
'work experience aboard' is the wordplay.
'work' becomes 'intern' (interning is a kind of working).
'experience aboard' becomes 'ship' (I can't justify this - if you can you should believe this answer much more).
'intern'+'ship'='INTERNSHIP'
Can you help me to learn more?
(Other definitions for internship that I've seen before include "being a trainee?" , "Work experience position" , "practical training programme" , "Trainee's spell" .)