Calories burned: 3-7 calories per minute depending on the form of the activity. Sitting in a boat while fishing is more like 3 while hunting big game and wading in the water while fishing are more likely to burn 7.
The Work: These were some of the first fundamental skills learned by mankind to ensure a more consistent food supply. Nomadic hunters during the Ice Age may have been the most dedicated to this work, living out their lives in a perpetual state of running across frozen tundra in search of the big kill: The Wooly Mammoth.
Accessibility: High, although the fishing part is far more easily accessible. These activities that were once necessary for vitality and survival (and still are for some) are still often done for recreation and alternative food sources.