Let me start by saying that this is a must-see for anyone living near the North Sea. You won't protect what you don't love, and you can't love what you're unaware about.
The film shows beautifully what goes on so close to our homes, but it fails to convey how we as humans are so dependant on nature. The director could've taken a firmer stance on nature protection and (extensive) fishing.
Direction/editing is a bit all over the place and I found it hard to find a clear syoryline. But the weakest point is the narration, also done by the director/cinematographer. It does not feel sincere or natural, and I often found myself mentally transported to the sound recording booth. Voice acting is quite the skill and a voice actor would've been a better choice I think.
The introduction felt out of place, although being nicely produced. It did serve as a decent introduction to the (somewhat) thematic Cousteau quotes (that kind of served as chapters?)
Despite its flaws, this is definitely a movie I highly recommend to see (in theaters if possible).