This one is
Leviathan from 1989, which was one of the "undersea menace" flicks from that time that included
The Abyss and
Deepstar 6.
Leviathan has a pretty sweet cast and in my opinion is really underrated. It was directed by George Cosmatos, who also helmed
Rambo and
Tombstone, and written by David Webb Peoples, who you might remember from
Blade Runner and
Ladyhawke.