How does Fisher work?
Four territories in a row are worth 2 bonus coins.  Adjacency doesn't matter.
Per the FAQ:

Q. If a Fisher Race occupies 4 regions in a row that borders the river, does that count as 3 pairs (AB, BC, CD) ?
A. No. That would count as 2 pairs, AB and CD. Note that these regions do not need to be adjacent to each other.