Forty years ago, when we went to Arran on holiday every year, my uncle took me out on a hired dinghy from King's Cross, at least 4 times each holiday.
The guy who hired the dinghys gave out Hermit Crab for bait as part of the hire. Worked a treat for big cod, haddock etc (in the days when the Clyde still had big fish).
When he had no Hermit Crab, he was always very apologetic and gave us Scallops instead!!
Can you imagine using Scallops for bait now?
Changed days indeed, 40 years ago they were used for bait, now they are a food delicacy and cost a fortune to buy!!