Keeping an Eye on the Submarine Bases of Your Enemies

Every navy has to know exactly where the various submarines of its enemies are at any given point there. So you have satellites that keep a close eye on all the naval ports and assets of your enimination. Aircraft are also equipped with technology that can detect magnetic anomalies deep under the ocean, which is the signature of a submarine. You need to know exactly how many submarins your enemy has. If you don't know it, you're not doing your job. You're failing. It's a cat and mouse game that's happening every single moment.