Shortly after the end of World War II, Trahan was the first farmer in the state of Louisiana to start producing crawfish in the same fields that he planted rice. This was done by rotating the crops. The rice was a summer crop, while the crawfish were a winter crop. According to biologist Percy Viosca, Jr., Trahan was given "full credit" for pioneering this method of producing a crawfish crop. This method of crawfish farming continues today and has grown into Louisiana's largest freshwater crustacean industry, with annual revenues that exceed US$300 million.