We didn’t make this up. The report uses available data from official bodies such as the OECD and the EU. Looking at these figures it's obvious that  trade liberalization of fisheries would lead to more over-fishing and would undermine food security in developing countries.

The paper shows how further liberalization will speed up the pace of over-fishing, further increase unsustainable aquaculture production, and have generally devastating consequences for fish, the wider marine environment, developing countries and the one billion poor people worldwide who depend on fish as their primary source of protein. The evidence for this from case studies and projections carried out by different organizations is overwhelming.