Publication Abstract

Use of size-based production and stable isotope analyses to predict trophic transfer efficiences and predator-prey body mass ratios in food webs

Use of size-based production and stable isotope analyses to predict trophic transfer efficiences and predator-prey body mass ratios in food webs

S. Jennings, K. Warr and S. Mackinson

Analyses of the structure and function of marine food webs are needed to estimate the potential yields of fisheries and the proportion of primary production required to sustain them. We show how size-based estimates of production, species richness and trophic level (from nitrogen stable isotope analysis) can be used to quantify trophic transfer efficiency, mean predator-prey body mass ratios and the mean ratio of the number of predator to prey species. In the central North Sea, we estimate transfer efficiencies of 3.7- 12.5 %, a mean predator-prey body mass ratio of 109:1 and a mean ratio of predator to prey species as 0.34. We show how differences in the fractionation of d¹⁵N affect our predictions. Our estimates of transfer efficiency and mean predator-prey body mass ratios are consistent with those obtained from costly and labour intensive diet and ecosystem modelling studies. Coupled analyses of size and trophic structure may provide a method for validating ecosystem models and assessing human impacts on marine ecosystems.

Reference:

S. Jennings, K. Warr and S. Mackinson, 2002. Use of size-based production and stable isotope analyses to predict trophic transfer efficiences and predator-prey body mass ratios in food webs. Marine Ecology Progress Series, 240: 11-20.

S. Jennings*, K. Warr* and S. Mackinson*

Marine Ecology Progress Series, 240: 11-20