What is the theme in The River Why by David James Duncan?

Fishing is an important theme in the book. The concept of fishing is an important one throughout the novel. Gus is a fishing prodigy who comes from two parents who fish—albeit in directly opposite fashions. The dichotomy between Ma's direct bait-and-hook approach and H20's fluid, elaborate fly-fishing style produces a unique fisherman in Gus. He is proficient in both styles, but cannot tell either parent how he caught his fish without a debate brewing in his household.