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EcoTroph workshop

EcoTroph (ET) is a modelling approach articulated around the idea that an ecosystem can be represented by its biomass distribution across trophic levels. Such an approach, wherein species as such disappear, may be regarded as the ultimate stage in the use of the trophic level metric for ecosystem modelling. By concentrating on biomass flow as a quasi-physical process, it allows aspects of ecosystem functioning to be explored which are complementary to EwE. It provides users with simple tools to quantify the impacts of fishing at an ecosystem scale and a new way of looking at ecosystems. It thus appears a useful complement to Ecopath.

EcoTroph is available as a plug-in module of EwE Version 6 and can be used either in association with an existing Ecopath model or as a stand-alone application, especially in data-poor environments. The workshop presented both the model and the use of the EcoTroph software. It was intended for scientists with some prior experience of the Ecopath with Ecosim (EwE) software.

Lecturers:

  • Didier Gascuel
  • Laura Tremblay-Boyer

Program

Friday September 4, 2009
9.00 ñ 10.30 Introduction
The trophic spectrum graphical representation
ET-Transpose: looking at an Ecopath model using EcoTroph
Tutorial: Building biomass and catch trophic spectra, the ET-Main table, forgetting species and looking at exploitation patterns at the ecosystem scale
Some examples of the use of trophic spectrum
10.30 ñ 11.00 Coffee / tea
11.00 ñ 12.30 Theoretical basis of the EcoTroph model
ET-Diagnosis: using EcoTroph for simulation and global diagnosis
Tutorial : Defining accessibilities, simulation of biomass and catch trophic spectra for increasing or decreasing fishing efforts, the Top-down effect, summary statistics and whole-ecosystem diagnosis
12.30 ñ 13.30 Lunch
13.30 ñ 15.30 The Catch Trophic Spectrum Analysis (CTSA): a VPA at an ecosystem scale
ET- CTSA: estimating ecosystem biomass from catches and using EcoTroph as a stand-alone approach in data-poor environments
Tutorial: Basic parameters and input data file, CTSA Forward and CTSA backward
ET-Dynamics: using EcoTroph with time series
Tutorial: Input data file, fitting time-series and hindcasting, catch and biomass forecast