What are the motifs in Stern Men by Elizabeth Gilbert?

Retaliation is a recurring idea. The lobster fishermen of neighboring Fort Niles and Courne Haven islands are fierce competitors, going to war four times in their history, dating back to 1902-13 when lobsters had not even become a luxury product. A second lobster war (1928-30) is inconsequential, but the third (1946) prevents the islanders profiting from the greatest single year in lobstering history. Competition grows fiercer as veterans of the Korean War return to their boats and reestablish territories. This is studied closely in a fourth lobster war (mid-1950s), which is thoroughly detailed in the novel.