On a humid evening in Tokyo’s Takeshiba neighborhood, a group of women head to a nearby theater, office workers stream toward a train station and chatting friends and couples relax on a strip of waterfront next to a mall. Among the bustle of city life, a few individuals in blue T-shirts were packing up wildlife survey equipment at a small, human-made mudflat nearby.

The fruit of their labor was swimming in a bucket filled with water from Tokyo Bay: nearly translucent shrimp, small crabs and fish no bigger than a finger.

A sign at the little beach’s edge explained that various local groups were working together for tidal flat restoration, and that participation was encouraged.