It's a very informative documentary. If one animal ceases to exist, it breaks the food chain. It also tells you that there is a place in the world where police/undercover police spy on you to see if you are against something terrible. They don't allow photography which is suspicious and they're hiding something. Marine animals are accidentally swallowing kilograms/pounds of plastic and washing up on the shore.
If you wanna know about the ocean and our impacts on it, watch this.