Partly because the HSBC says not to. More importantly, the price of fish is likely to accellerate more than the cost of catching it (including boat fuel price hikes). In addition, I understand that Iceland and Greenland are likely to be climate change winners (although I would need to do more research on this. The country is politically stable with and educated population that can participate in the information age.

Another point for further research would be the extent to which Iceland is trying to diversify its' economy. Is the money raised being allocated to economic infrastructure or simply to roll over existing debt?