This png file shows that International travelers must submit through the portal. However, the portal no longer functions. Instead, in the portal page itself, the CDC is now referred to as the authority on this subject. Dated info?

Clearly, referring to the CDC as the authority on this subject makes all previous published communications questionable, as the CDC has exempted sea passengers from testing on arrival.

The evidence shows that the different USVI government entities involved did not coordinate a response, so there is conflicting guidance on the internet. There seems to be disparities between what appears to be the regulations and what appears to be in practice. Hope they clarify in writing soon. In the meantime, plan on testing for return is my point of view.