Figure 2.

Maps illustrating changes in MTI (i.e. mean trophic level of fisheries catches) from the early 1950s to the present. (a) Changes in grand mean TLs, corresponding to ^2.0MTI (see text), based on FAO statistics disaggregated using method of Watson et al. (2004); (b) same data, but with trophic levels below 3.25 not included, and hence with maps representing changes in the values of ^3.25MTI. Note: increase of the areas with negative changes, indicating that ^3.25MTI is more sensitive than ^2.0MTI. (In both panels, the straight borders between colours, and the areas of positive change, largely represent artefacts of the underlying FAO statistics; the white areas in panel (b) represent cells with catches of less than 1000 t.)