What does it mean for a vessel to be 'engaged in commercial fishing'?

The phrase 'engaged in commercial fishing' refers to activities where vessels are utilized specifically for fishing purposes that are intended to be sold or profit-generating, often involving certain types of equipment and methods. When a vessel is fishing with equipment that restricts maneuverability, it is specifically indicating that the vessel is likely using gear such as nets or traps. This type of fishing requires the vessel to be in a fixed position or significantly limit its movement, which is characteristic of commercial fishing operations that emphasize efficiency and productivity over recreational boating activities.

In contrast, other options describe scenarios that do not encapsulate the essence of commercial fishing. For example, using trolling lines may indicate recreational fishing, while being moored in a designated fishing area doesn't inherently imply that commercial fishing is occurring. Similarly, fishing from a recreational boat implies a non-commercial intent. Therefore, the correct answer effectively represents the manner in which commercial fishing operations often function, highlighting their use of equipment that may limit a vessel's movement.