The theme also has a secondary meaning. Not only does it feel like you are diving into the ocean, it also is a look into yourself. While Anthropocentric had an outward focus, Pelagial travels inward with lines like "How much control do we have over what we wish for". It's also not as open in it's questions of Christianity. No longer focused on questioning the religion itself it takes a look at the person and their beliefs and what drives a human being.
The Ocean have a definitive style carried on through the last 3 albums they have done. Pelagial is the easiest to listen to. The riffs aren't as harsh as Anthropocentric and it feels a lot smoother as a whole. As always the lyrics are beautiful and an art in themselves. It also manages to maintain its momentum better than the previous albums, even when it slows things down like in 'Abyssopelagic I: Boundless Vasts', The song so calmly almost as to lull you to sleep, in a good way. Even as it fades into the beginning of the next song, it works. It feels like a whole cohesive concept album.
Pelagial is The Oceans best work to date, it is a master piece of an album. There are no words to express this album. The closest I can come is with the word experience. This is an album that needs to be experienced in its entirety to get the whole picture. While the songs taken on their own still stand well, together they form a complete journey into the depths of The Ocean. They set out to accomplish a great task of a concept album, and they succeeded with flying colors.