“The JCG’s decision to consider the introduction of UAVs was prompted by the Japanese government’s decision in December 2016 to adopt a new policy for maritime security. The policy is designed to strengthen the functioning of the JCG in response to the recent activity of Chinese fishing and government vessels in the waters around Japan. Therefore, it was decided to consider the introduction of UAVs for the purpose of continuous monitoring of these foreign vessels, especially those operating within Japan’s vast Exclusive Economic Zone (EEZ).In fact, Japan’s territorial waters, plus its EEZ, are the sixth largest in the world, and it would be difficult to keep watch of such a vast area with manned aircraft and patrol vessels alone.”
Significantly, the Japan Coast Guard will be sharing information from their UAS with the Japanese Maritime Defense Force (their navy).
Seems the Japanese started much later on this than the USCG, but is now moving much faster.
Perhaps significantly the MQ-9B has a submarine detection capability using sono-buoys.