How to tag regions (channels) between islands

Not sure if I’m right, so I would like to know what others think about.

Between the carribean islands Saint Vincent and Bequia is a huge passage (more than 8km wide, the length is not even defined we’re in the open sea). It’s called “Bequia Channel”. How to tag this passage correctly?

There’s the tag “canal”, but this seems only to be used in a river environment. Would it be the correct way to add a area between the two islands and tag it as canal? Remember we’re talkin about a sea environment.
Or does somebody have another idea about how to solve the problem?

Thanks for your contribution…