 From the early 15th century on the Shetlanders had sold their goods through the Hanseatic League of German merchantmen . This trade with the North German towns lasted until the 1707 Act of Union when high salt duties prohibited the German merchants from trading with Shetland . Shetland then went into an economic depression as the Scottish and local traders were not as skilled in trading with salted fish . However , some local merchant @-@ lairds took up where the German merchants had left off , and fitted out their own ships to export fish from Shetland to the Continent . For the independent farmer / fishermen of Shetland this had negative consequences , as they now had to fish for these merchant @-@ lairds . 
