Have you ever seen an anime/manga where that has a series within a series(like a tv show) with a ridiculous premise? One I can think of is Kamakiri Man from Zatch Bell about a giant praying mantis with a human head that fights crime like a Saturday Morning cartoon. A concept so silly and ridiculous that you wonder how a series about it would play out on it's own. Shakunetsu no Nirai Kanai is pretty much that concept made into an actual series.

Coming from the mind Ryuuhei Tamura (Creator of Shonen Jump's Beelzebub), Shaknetsu no Nirai Kanai (Hardboiled Cop and Dolphin) is his next foray into Weekly Shonen Jump and the result is very similar to Beelzebub for his benefit.

The series starts off with it mainly being a comedy manga, with the absurdity of the idea of a Dolphin Cop being the main gag going forward. Jokes about dorsal fins, people questioning why he's a Dolphin, and nautical language (using Fishsticks as a substitute for "Oh shit") are the types of comedy you'll see early on. The fun is seeing how serious it's played by Orpheus and everyone just accepting who he is as a person as the series moves on.

To pair up with Orpheus we have our main character Samejima. Samejima is the early straightman to Orpheus and soon enough starts becoming a comedy machine himself. Making jokes, goofing around, and having some wonderful expressions while also being a badass cop. His character gradually shines more and more as the two of them start working together and caring for each other as a team.

The third anchor for the story would be Chako, a little girl who is viewed as an Oracle to a cult and is Orpheus' daughter. She has mystical powers but generally is seen doing this to turn sealife into half human hybrids, and at a certain point helping Samejima breathe underwater. She's playful, innocent, and cares for both Same and Orpheus and is a center point for the story.

Without giving too much away the plot later involves Undersea Gangs who want to kidnap Chako, and these gangs also involve Human/Sea Creature hybrids. This is where Tamura's experience from Beelzebub comes into play making some very fun fight scenes that got a ton of that classic "Real life element explained in the manga to make the fight cooler".

As of the time of writing the series has had a pretty big plot point happen with a new big bad showing up. It's going into the battle direction but still is maintaining it's ridiculous concept so that end I've been enjoying it.

Before I wrap up I'd like to say the setting for this series being a small tropical island is a fantastic choice. It allows for some really good looking setpieces, one fight in particular I loved took place underwater near a barrier reef and the shading and lighting from the sun through the waves really added to the atmosphere.

All in all as the series is still going on I'd recommend it. The beginning is full of your usual comedy, but don't let that dissuade you as the story becomes much more shonen/action filled as it progresses and it surprisingly works.