Biggest issue for AUVs is how water attenuates radio, meaning this will have to surface to phone home. Guessing it will mostly be used for surveillance.
Although the US (allegedly) no longer operates them, they (and Russia and China) have used extremely low frequency communications stations spread out over miles to communicate with submerged submarines. Tensions are much lower now so submarines can take the risk of surfacing for communications checkins but I'm sure that the ELF stations could be recomissioned fairly quickly if the need arose
Given its size, it could hold a number of cheap small satellite communicators (ie garmin inreach) that could be deployed to slowly float to the surface and phone home as needed.
