What did Duane claim to be doing on the day of the field trip?

Duane claimed to be snook fishing in Marco on the day of the field trip, which indicates that he was engaged in a recreational activity centered around fishing. This choice likely highlights an experience that emphasizes leisure and enjoyment, contrasting with school-related activities. Snook fishing in Marco is a specific and vivid detail that suggests Duane was enjoying a location known for its fishing opportunities, which can serve to illustrate his interests and lifestyle. The specificity of this activity would make his claim memorable and distinct from more common activities that might not stand out as much. Engaging in such a notable experience could also suggest an alternative to typical school engagements, such as field trips, thereby reinforcing his character's involvement in more adventurous pursuits.