I want to write a story about a nomadic people who migrate along the route of the North Atlantic gyre, the clockwise current in the North Atlantic Ocean - the North Atlantic Equatorial Current, the Gulf Stream, the North Atlantic Current, and the Canary Current. 

Trying to imagine what living under would be like, and the first issue I run into is - why are they nomads? Of course, the current is always pushing them in the clockwise direction, but why go with it? Why not pick a sheltered valley along the way and stay there, or anchor your homes to the bottom? The reason surface people are nomadic are usually related to following food supplies or escaping weather cycles (I think, I may need to do more reading). But the current would actually bring them food if they stayed in one place, I think, and if they were worried about the surface weather, staying in one place would probably result in less variation than moving with the current.

Any thoughts? Thanks!