Estimates of the size of the benefits of marine ecosystem services suggest that these are considerable (for a review of a selection of such studies see Annex 1 .A2), but much work remains to be done. Hence, as noted above, while many aspects of ecosystem services are taken into account here, the quantitative focus of this report is on ocean-based industries. To compare an industry’s contribution to the economy across countries, the share of total GVA is preferred to the share of GDP.