What is the primary function of visual distress signals?

The primary function of visual distress signals is to indicate an emergency situation. These signals are crucial for ensuring safety on the water, as they alert nearby vessels and rescue services that an individual or crew is in distress and requires immediate assistance. The use of visual signals, such as flares or flags, is standardized to make it clear to others that help is needed, enhancing the chances of a quick response and successful rescue.

Other options provided do not align with the intended purpose of these signals. For example, confusing other boats or improving fishing success does not serve any safety-related function. Additionally, mapping the waterway is unrelated to distress signals and involves different navigational tools and techniques. Therefore, the only option that accurately reflects the role of visual distress signals is their function in signaling an emergency.