Slave ships and captains
Stephen D Behrendt, in ‘The captains in the British slave trade from 1785 to 1807’ [PDFView Volume - The Historic Society of Lancashire & Cheshire (Vol 140, 1990), pp79-140] found that, in a sample of Liverpool slave ships, about 20% of the captains were Scots. In Bristol, in contrast, there were few Scots.
One exception, detailed here, is the Bristol captain James Fraser, from Kiltarlity (Inverness-shire).