Hello Odexey,
Unfortunately, I will be Rejecting your map.
The theme is somewhat original, there are a lot of maps related to fish, oceans etc. none exactly like this though.
The build is really nice, it is nicely shaped and detailed, and overall very well built.
The parkour is quite repetitive, as most of it is fences & ladders. Try to experiment with a larger variety of blocks and items when building maps, as this will overall make your map more enjoyable to complete.
I felt like some of the jumps were a bit cramped, putting a lot of jumps very close together where you could possibly stretch it out a bit more, with a fewer number of jumps. It's up to you, but it could also work changing the map to an easy map, making some jumps a bit easier and having it as an easy length map.
The length and difficulty are good for a medium map.
Thanks for submitting your map! I hope to see more maps from you in the future.