What does it signify when you see a fishing vessel with a man on deck repeatedly raising and lowering his arms outstretched to each side?

When a fishing vessel has a crew member on deck repeatedly raising and lowering his arms outstretched to each side, it signifies that the vessel is engaged in fishing activities. This action is a well-known signal used by fishing vessels to indicate their operational status to other vessels in the vicinity. It is essential for other mariners to recognize that such a vessel is likely to have gear in the water and may pose a risk of entanglement if navigated too closely.

This type of signaling is based on the common practices outlined in the International Regulations for Preventing Collisions at Sea (COLREGs) and reinforces the need for vigilance in maritime navigation, especially in areas where fishing operations are taking place. Understanding these signals helps promote safety and situational awareness on the water.