Field survey of sediment, benthic organisms, and spawning site of Marbled flounder off Akanehama, Tokyo Bay, in December 2022

On December 27, 2022, in collaboration with the Habitat Creation Project Team under the Public-Private Cooperation Forum for Tokyo-Bay Restoration and the Chiba Prefectural Fisheries Research Center, we conducted a survey of spawning grounds for marbled flounder, including bottom sediment and benthic habitats, off Akanehama in northern Tokyo Bay.
This survey was conducted based on a policy proposal from the Public-Private Cooperation Forum for Tokyo-Bay Restoration to the Tokyo Bay Regeneration Promotion Council (WEB of Ministry of Land, Infrastracture, Transport and Tourism followed by an implemented project WEB of Kanto Regional Bureau of Ministry of Land, Infrastructure, Transport and Tourism and WEB of the Public-Private Cooperation Forum for Tokyo-Bay Restoration). This survey is also positioned as a monitoring survey for the implemented project.

We gathered at Funabashi Port at 8:00 a.m. and divided the survey between two boats. In some areas where bottom sediment had improved by the project, we could see many marbled sole eggs on board.

The weather was clear; Mt. Fuji could be seen clearly.

Tokyo Skytree was also clearly seen.

A weighted net made by the Chiba Prefectural Fisheries Research Center was towed a fixed distance to collect bottom sediment from the surface layer.

The bottom sediment collected was washed away by seawater from outside the net.

Finally, the remaining components of the net (expected to include marbled flounder eggs) were collected in a container.

Sediment samples were also be collected to analyze the benthic environment and benthic organisms.

Group photo of the survey members. Thank you for the hard work.