Suruga Bay

Numerous rivers—especially the major Fuji, the Ōi, and Abe rivers—empty into its western portion, giving that area of the bay a seabed rich in submarine canyons and other geographical features, whereas at the bay's easternmost end, only the Kano River empties into a pocket called Uchiura-wan at Numazu, Shizuoka, where the Izu Peninsula connects to Honshu, giving the water greater transparency and leaving the seabed largely flat except for a number of small rocky islands, some joined to the mainland by tombolos.

This seabed variety coincides with coastline differences as well: The western and central sections of the Suruga Bay coastline, roughly from Shizuoka to Numazu, are characterized by sandy beaches such as those at Yuigahama and Tagonoura, whereas the eastern and northeastern stretches from Numazu down the southwestern coast of the Izu Peninsula to Irōzaki, are generally rocky.The bay is open to the Philippine Sea/Pacific Ocean to the south, but is mostly protected from oceanic waves by Izu Peninsula.

This, coupled with the seabed and water characteristics mentioned above, results in conditions favorable to fishing, sailing, windsurfing, swimming, and research on deep-sea organisms.

180,000) produced 2.4 million short tons (2.2 Mt) of waste water every day – equivalent to the daily sewage of Tokyo at the time (1970 pop.

The sulphur-laden sludge was so thick that it threatened to block the harbour, requiring dredging that severely damaged the marine life.