LAUSR

Abstract As part of the Environmental Impact Assessment and Habitats Regulations Assessment process, developers are required to assess the indirect effects of fish entrapment however, presently there is little guidance to support quantitative assessments of food resource losses to higher trophic levels. To address this gap, a detailed and quantitative tool termed Dietary Equivalence Analysis is presented in this paper. Dietary Equivalence Analysis combines bioenergetic modelling with dietary and demographic information to express entrapment predictions in terms of the number of marine predators, or the proportion of a population, that would be sustained by the biomass of fish prey had it not been entrapped. The application of this tool is demonstrated by way of a worked example and includes a sensitivity analysis using Monte Carlo simulation to determine the influence of input parameter uncertainty on dietary equivalence estimates. It is shown that the Dietary Equivalence Analysis framework can be used to develop project- and regional-specific quantitative assessments for a number of marine predators. This is considered to provide competent authorities with a new and more realistic perspective from which the magnitude of predicted fish entrapment effects can be viewed and assessed.