FIGURE 2. Fisheries, both marine and freshwater, are characterized by a decline of the mean trophic level in the landings, implying an increased reliance on organisms low in food webs (data from FishBase²⁷, with Peru/Chile excluded owing to the dominance of Peruvian anchoveta; see also Fig. 1).

Freshwater fisheries have lower trophic level values overall, indicating an earlier onset of the 'fishing down' phenomenon²⁹. The trend is inverted in non-Asian aquaculture, whose production consists increasingly of piscivorous organisms, as illustrated here for Norway (a major producer, yet representative country)⁸⁵.