Game analysis of ship ballast water discharge management —triggered by radioactive water release from Japan.

As Japan has announced its decision to start discharging radioactive water into the Pacific Ocean, it's expected that global marine environment pollution will worsen due to the contaminated water, posing a new challenge to the ballast water management system dominated by the flag state. In this context, this paper studies the equilibrium strategies on ship ballast water discharge controls between the flag states and the port states in different situations. Through a numerical study, we analyze how the ballast water discharge location, decision sequences of relevant states, the role of the International Environmental Protection Organization and its aid strategies impact the control strategies by the flag states and the port states. In the event of radioactive water discharge, the flag state controls alone do not yield satisfactory results, and the port state control is effective supplementation to the flag state control to mitigate risks of marine pollution. Furthermore, where the International Environmental Protection Organization takes reasonable aid steps, the flag states are incentivized to take control measures. [Display omitted] • The challenges of ship ballast water management will be much severer after nuclear water released by Japan. • Supplementary role of Port State Control to Flag State Control in ballast water management is discussed. • The role of International Environmental Protection Organization in ballast water management is discussed. • Policy suggestions are proposed for ballast water management under the background of nuclear water release. [ABSTRACT FROM AUTHOR]