Pirate Borg (Limithron/Luke Stratton) Caribbean setting has a 6-mile long fissure running from the yucatan to cuba.

My first question was what would the total volume of water displaced be if that fissure were 1-mile and 2-miles deep;

and secondly, what impacts would that have on the sea levels and the Caribbean at large?

Setting is 1715, thanks so much for any help!!