Beyond fishing and sheep they have their volcanos to keep them warm.
Alas, fishing alone can't keep them at middle class income levels. This leaves them few choices ~ maybe institute surfdom again, or convince a lot of them to emigrate to America or Canada. They once lost over 40% of their population over just one eonomic collapse.
A few years ago I had looked into investing in Icelandic CD’s - they were paying over 13% interest just to park your money in their banks. Glad I took a pass.