I used to work as a commercial fisherman. Any buoys or markers that have visble surface floats, will always run north and south. When you come to a spot that has two markers (buoys)they are called splits and can be passed through as long as there is enough space to get your gear through.
Any markers that have no visible surface floats are referred to as bottom nets and can run north and south or east and west.
If you approach two markers side by side....east and west.. they will be always be set east and west. They would not be apart far enough to run two strings that close north and south.
I was out fishing for perch yesterday and it seemed the nets that were in close to the shoreline were running east and west. The ones we seen around 40 to 45 ft were running north and south. However there was a string of bottom nets we drifted onto, just south and east of Bruce harbour that run east and west in 38 ft of water.
Hope this is helpful and not to confusing.