Application of Specific Eco-Exergy to FAO Fisheries Data

We have applied specific eco-exergy to data on fisheries landing and on aquaculture from FAO. Specific ecoexergy gives a weight to each species, depending on the genetic information content. The biomass for each species is multiplied by this factor and then the sum of all values divided by the total biomass. Therefore, this value is independent of the total catches and reflects the quality in terms of information content of what we are extracting from the whole oceans or producing by aquaculture. The objective was to analyze the trends of this indicator. In addition, we have detected possible change points in the gradient at unknown times using likelihood ratio test, with the null hypothesis of linear relationship. We intended to analyze these detected change points against well-known historical events in all defined FAO areas. The results show a continuous decline, since the 70's, for the world marine specific eco-exergy. On the contrary, the same analysis applied to aquaculture shows no decreasing trend.