The management of marine resources pose a difficult commons problem as monitoring behavior is difficult and benefit flows from the resources are uncertain. Implementing individual transferable quota (ITQ) is a management regime in which quasi-property rights are assigned for an often mobile and uncertain environmental resource, fish or marine invertebrates. This thesis addresses sustainability impacts of ITQ’s as a fisheries management tool. The findings demonstrate that fisheries management regimes in which fisheries opportunities are allocated as quota and / or are allocated individually experience reduced overfishing compared to controls that do not have these attributes (Paper I), however the analysis found less support for transferability and no support for longer duration being associated to any change in the probability of overfishing. In addition, a longitudinal study showed that with an adaptive design ecological and economic goals could be balanced in an important mixed fishery in Iceland (Paper II), and based on such findings suggested that several policy changes could be implemented to modify the ecological risk of catch-quota balancing allowances. Additional longitudinal analyses allowed to conclude that rapid consolidation in an important small-boat fishing sector in Iceland, which may have had negative implications for local fishing communities (Paper III), and that on average since the introduction of ITQ’s total amount of quota traded stayed below around 60% for the main commercial species in the Icelandic ITQ system. Moreover, the results of Paper IV also show that in case of a credible announcement of quota revocation in the future there would be scope for policy reform. Finally, research is beginning to emerge that shows that marine species are unequally affected by climate change. In a final chapter the analyses show that under different scenarios of global change a re-shaping of the Icelandic foodweb is likely (Paper V). The re-shaping of the foodweb will be to the benefit of some resource users and to the loss of others. In general, the findings from all the analyses together demonstrate that there could be benefits to individual quota implementation for fisheries sustainability and that some of the hypothesized trade-offs could potentially be balanced, the thesis highlights ways forward in investigating the common pool problems in fisheries management.