Pauly, D., and V. Christensen. 1995. Primary production required to sustain global fisheries. Nature: 374: 255-257.
The mean annual world fisheries catches for the years 1988-1991 was split into 39 species groups, and each was assigned a fractional trophic level ranging from 1.0 (edible algae) to 4.2 (tunas), based on 48 published trophic models, providing a global coverage of all major types of aquatic ecosystems. The primary production required to sustain each group of species was then estimated from a derived mean energy transfer efficiency of 10% between trophic levels.
The primary production required amounted to 6.2% of global
aquatic primary production, 3 times previously estimated. By
ecosystem type, the requirements were only 1.6% for open ocean
systems, but amounted to more than 20% for upwelling, shelf and
freshwater systems. The analysis were done by splitting the world
catches into 39 species groups (i) for which fractional trophic
levels (TLi) were computed based on 48 published trophic models;
average ecotrophic transfer efficiency between trophic levels
(TE) was estimated to 10% based on estimates from the same
models, and the catches (Ci) were raised to Primary Production
Required (PPR) using the relationship
The implications of these findings for sustainability and biodiversity are alarming.