What is the best method to control swimmer's itch at a beach?

The best method to control swimmer's itch at a beach involves adding copper sulfate. This chemical is effective because it acts as a molluscicide, targeting the intermediate hosts, typically snails, that contribute to the life cycle of the parasites responsible for swimmer's itch. By reducing the population of these snails, the number of parasites that can infect swimmers is also diminished, which helps to control outbreaks of this unpleasant condition.

While other methods like installing barriers, closing the beach, or increasing water circulation may seem beneficial, they do not specifically address the root cause of swimmer's itch. Barriers might prevent some interaction between snails and swimmers but do not eliminate the problem. Closing the beach is not a practical long-term solution and can negatively impact public enjoyment and local economies. Increasing water circulation can improve water quality but may not sufficiently reduce the presence of the parasites that cause swimmer's itch. Thus, adding copper sulfate directly targets the problem more effectively.