Eels travel with the Gulf Stream across the ocean and, after one to three years, they recruit to coastal areas they migrate up rivers and streams, overcoming all sorts of natural challenges — sometimes by piling up their bodies by the tens of thousands to climb over obstacles — and they reach even the smallest of creeks.
They can move themselves over wet grass and dig through wet sand to reach upstream headwaters and ponds.

They make a journey of 6,000 km back to the same pond they were born!

Our concern is not about how they make it (it is unknown till now)
Whichever the method that they use, it will need external data about the location (and route) to take

This external source must be intelligent and have a purpose to send this data to eels

GOD