Over here, marinara = seafood.
yeah, this. On a side note, if you're ever in Australia and you see 'marinara' sauce on the menu, expect to get red sauce with big chunks of various seafood in it.

Thankfully I never made this mistake (the very idea of red sauce with seafood in it is

to me. Love them both separately, but together? no.) I did confuse the hell out of a friend when I said I'd love to get a side of marinara sauce with some pizza we were having, though.
This could be applicable in the UK, but I've not been looking so I can't say for sure. Just wanted to let you know to be wary of the term if you do see it!