Firstly a definition search told me dulse is "a reddish-purple seaweed. Used in soups, salads, and vegetable dishes. Very high in iron."
Quite aside from some a lovely variety of photos of dulse fresh-picked, dried and packaged, google image search also led to Laurie Murison's informative page (kwouted below) where I was interested to learn how dulse is picked:
every two weeks--corresponding to the new and full moons. The pickers clamber over slippery rocks, tearing off only a portion of the dulse leaving the holdfasts and part of the fronds. ... Dulse pickers often travel along the shores in dories, wooden, flat-bottomed boats that can be safely landed on the rocky shores. Traditionally rowed, most dories now have small out-board motors. They may use headlamps (similar to the ones miners use) when the low tide occurs at night.
I was also fascinated to read how many different ways it is eaten. Read for yourself: