Shetland is a windswept, barren archipelago a hundred or so miles northeast of mainland Scotland’s northernmost tip. I fell in love with Shetland when I was 16. I had gone there to photograph otters and I’ve been visiting it regularly ever since. It’s very windy a lot of the time and if it’s not raining it’s usually cloudy. However, when the wind settles and the sun comes out, few places on Earth can beat it for beauty. I took this photograph of my friend Henry on just one of those days. Henry had offered to take me out on his boat around the back of the island of Vaila to do a spot of fishing. It was flat calm out at sea and that gave us the chance to go through this arch.
What does "to do a spot of fishing" mean?