Final answer:
The provided information does not specify the number of supertankers or containerships missing annually but indicates that incidents of ships disappearing without a trace are uncommon due to modern technology and stringent regulations.
Step-by-step explanation:
The question of how many supertankers or containerships are reported missing each year without a trace does not have a straightforward answer. The data provided, while thorough in detailing the operation and management of ballast water (BW) and the types of ships that arrive at U.S. ports, does not directly specify the number of missing vessels. However, it is known that with the advances in technology and international regulations, incidents of ships disappearing without a trace are rare. The data does highlight the importance of efficient management and operations in the context of global shipping, and the role of different ship types in ballast water discharge and potential biological invasions.
Much of the global cargo movement is dependent on the operation of large container ships, which move significant amounts of cargo across vast distances. Furthermore, the biofouling species and the effect of ballast water discharge from these vessels highlight the need for comprehensive management of the maritime environment.