Simplify the following text for a Grade 5 native English-speaking person.
Original: The Old Dock was filled in and is now Queens Gardens , St Andrews Dock was closed off and silted up ( some of it is now a retail park ) , the Victoria Dock closed in the 1980s and is now a housing estate , the Railway Dock closed in the 1960s and was later used as an extension to the Hull Marina .
Simplified: The dock was in use until the 1975 when the fishing industry was moved to Albert Dock at which point the dock closed . Partial filling in of the dock began in the 1980s .