Hard-Boiled Cop and Dolphin (manga)

Hard-Boiled Cop and Dolphin (灼熱のニライカナイ, Shakunetsu no Nirai Kanai) is a manga created by Ryūhei Tamura. The first chapter was released on June 29 2020 in Shonen Jump Issue #30.

Overview
Meet hard-boiled cop Boyle Samejima. He's just been assigned to the remote Ogasawara Islands. There he finds coworkers, a mysterious young girl and a dolphin for a partner?! Cop x girl x ocean! Welcome to the craziest hard-boiled cop story you'll ever read!