Trophic Levels in Fishbase and Sealifebase

The “fishing down the food web” phenomenon was based on two parameters: 1) disaggregated (species level at best) catches, available from national statistics or the FAO fisheries statistics online database; and (2) trophic level of the species, available via FishBase (www.fishbase.org) for fish and now via SeaLifeBase (www.sealifebase.org) for all other marine organisms. The mean trophic level of the catch was first introduced as Figure 4 (p. 46) of the chapter on “Graphs in FishBase” of Rainer Froese and Daniel Pauly’s “FishBase 97: Concepts, Design and Data Sources”. This also introduced the estimation of trophic levels in Box 16, “Trophic levels of fishes” (p. 127; Daniel Pauly and Villy Christensen). This version of FishBase (available as CD-ROM) contained 5,700 food items for 1,206 fish species and 1,100 diet compositions for 690 species, and trophic levels for almost 2,000 species, most commercially exploited. This large collection of trophic level data made possible the estimation of the mean trophic level of the catch for a number of fisheries and the one publication that started this whole debate. Since then, we have incorporated a number of ‘peer-reviewed’ changes to the way trophic levels are estimated in FishBase, which we outline in this contribution.